Ch. 35 – Mollusks & Annelids Mollusks and annelids are grouped together because they were the 1st organisms to develop a true.
Download ReportTranscript Ch. 35 – Mollusks & Annelids Mollusks and annelids are grouped together because they were the 1st organisms to develop a true.
Slide 1
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 2
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 3
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 4
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 5
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 6
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 7
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 8
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 9
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 10
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 11
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 12
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 13
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 14
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 15
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 16
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 17
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 18
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 19
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 20
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 21
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 22
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 23
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 24
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 25
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 2
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 3
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 4
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 5
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 6
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 7
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 8
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 9
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 10
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 11
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 12
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 13
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 14
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 15
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 16
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 17
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 18
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 19
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 20
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 21
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 22
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 23
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 24
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.
Slide 25
Ch. 35 – Mollusks & Annelids
Mollusks and annelids are grouped
together because they were the 1st
organisms to develop a true coelom.
– This suggests that these two groups of
animals may have evolved from a common
ancestor.
The coelom provides space for a
circulatory system to function without
interference from other organs. They
can contract muscles without hindering
the movement of food through the gut.
Both have the same 1st stage in larva
development which is called a
trochophore.
Phylum: Mollusca
– Snails, clams, octopuses,
oysters, squids
– Video
– Mollusk is Latin for “soft”
– Most have a shell to protect
them and are soft inside the
shell.
– Develop from a trochophore
larva which is a free-swimmer.
Cilia helps them swim.
Mollusk Characteristics
Most are filter feeders (100,000
+ species).
True coelom
3 main body parts: muscular
foot, head, & visceral mass.
Circulation, respiration,
digestion, excretion,
reproduction, nerve impulses.
Body Arrangement
1. Muscular foot – used for locomotion.
2. Head – has a cerebral ganglia &
mouth.
3. Visceral Mass – contains many
organs.
4. Mantle – protects the visceral mass.
It secretes a shell in most mollusks.
Shell is made of calcium carbonate.
– How does the mollusk breathe with a
shell?
Gills are used for respiration.
4 Classes of Mollusks
1. Class: Gastropoda – snails &
slugs
– Largest class of mollusks
– Gastropoda means “stomach
foot”
– Slugs have no shell
– Snails have a single shell
– The body mass can turn 180
degrees this is called torsion
Snails
Gills for respiration
Survive in moist environments
Open Circulatory System
Hemocoel – open body cavity
for blood circulation.
Radula – a saw-like tongue
made of chitin.
Use foot to move with wavelike
contractions.
2. Class: Polyplacophora –
chitons
– Polyplacophora means
“many plates”
– Their shells consist of 8
overlapping plates.
3. Class: Cephalopoda –
squids & octopus
– Cephalopod means “head
foot”
– They have tentacles and a
sharp radula to kill prey.
– Closed Circulatory System –
blood circulates in vessels.
Squids
Largest invertebrate
Giant squid are up to 3 meters
long.
Squid have the ability to squirt ink.
They have the ability to change
colors.
– Video
Squids have separate sexes
Squid & octopus use jet propulsion
to move.
Video
4. Class: Bivalvia – clams &
oysters
– Bivalvia means “two
halves”
– They are sessile & filter
food from the water.
– They have a muscular foot
– They don’t have a distinct
head
– If a piece of sand grain gets into
its shell the mantle coats the sand
grain with secretion to form a
pearl.
Clams
– Filter feeders
– Have incurrent siphon for water
to enter and an excurrent siphon
for water to exit.
– Have separate sexes like most
mollusks.
Body parts of a clam
Dissection
Clam Video
Annelida
Phylum: Annelida – earthworms &
leeches
– Video
Characteristics
– Body is divided into segments
metamerism
– True coelom
– Well developed organ system
– Most have setae external bristles
– Some have parapodia fleshy
appendages
– Video
3 Classes
1. Class: Polychaeta –
marine annelids
–Have setae & parapodia
–Have antannae (the only
class)
–Some are free-swimmers
2. Class: Hirudinea –
leeches
–No setae
–Live in calm bodies of
freshwater
–Sucker at each end
–Smallest class of annelids
•Video
3. Class: Oligochaeta –
earthworm
–Have setae – used to
anchor their segments to
soil as they burrow
through the soil.
–Contract and expand in
order to move
•Video
Main Systems of an Earthworm
Digestive system
Worms feed on organic matter in
the soil.
Worms loosen & aerate soil.
Travels in the following pathway:
prostomium (lip) mouth
pharynx esophagus crop
gizzard intestine
Crop stores food, gizzard
grinds food
Circulatory system
Closed system – have
blood vessels
Aortic arches – serve as a
heart
–5 pair
Have a dorsal & ventral
blood vessel
Respiratory & Excretory
systems
No lungs or gill directly
through the skin
When it rains why do worms
migrate to the surface?
Nephridia is the excretory
organ that eliminates waste.
Reproductive system
Hermaphrodites
However, they can’t
fertilize their own eggs.
They attach at the
clitellum & secrete a
mucus layer in which the
egg & sperm are placed in.
Sperm is injected from the
seminal receptacle.
Eggs are released from the
oviducts.