Transcript Platyhelminthes, Nematodes, molluscs

BSC 2011L
Animal Characteristics

Symmetry
 Radiata – radial symmetry, diploblastic (2
tissues)
 Bilateria – bilateral symmetry, triploblastic

Body Cavity
 Acoelomates – no cavity
 Psuedocoelomates – false coelom, not
completely lined by mesoderm derived tissue
 Coelomates – true coelom, room for organs in
body cavity lined with mesoderm tissue
 Protostomes – 1st embryonic opening becomes mouth
 Deuterostomes – 1st embryonic opening becomes anus
Animal Taxonomy (cont.)

Domain Eukarya
 Kingdom Animalia
○ Invertebrates
 Parazoa
 Emetazoa – true tissues, symmetry
- RADIATA – radial symmetry
- BILATERIA – bilateral symmetry, triploblastic
- Acoelomates
• Phylum Platyhelminthes – flatworms
▪ Class Turbellaria – free living, Planaria
▪ Class Tremetoda – flukes, Fasciola hepatica
▪ Class Cestoda – tapeworms
- Pseudocoelomates
• Phylum Nematoda – roundworms, Ascaris
• Phylum Rotifera – rotifers
- Coelomates
• Protostomes – 1st opening becomes mouth
▪ Phylum Mollusca
• Class Polyplacophora – chitins
• Class Gastropoda – anails
• Class Bivalvia – Clams, scallops
• Class Cephalopoda – octopus, squid
Phylum Platyhelminthes

Flatworms
 Can be free living
or parasitic
 Hermaphroditic
 Acoelomates
○ One opening
 Digestion –
gastrovascular
cavity
 Circulation –
gastrovascular
cavity
Phylum Platyhelminthes
Phylum Platyhelminthes
Class Turbullaria













Animal:
Symmetry:
Body cavity:
Digestion:
Circulation:
Segmentation:
Appendages:
Nervous:
Habitat:
Respiration:
Excretion:
Locomotion:
Support:
Planaria
Bilateral
acoelomate
gastrovascular cavity
gastrovascular cavity
none
none
brain, 2 ventral nerve cords, ladder-like
aquatic
diffusion
flame cells
muscles
none
Planaria model
Phylum Nematoda







Aquatic habitats, damp soil
Parasitize both plants and animals
Pinworms and hookworms cause intestinal
problems in humans and other animals
Trichonella causes trichonosis (attaches to
intestinal wall and robs host of nutrients)
One species causes what we call
elephantiasis
Digestion – mouth and anus
Circulation - none
Phylum Nematoda
Phylum Nematoda













Animal:
Symmetry:
Body cavity:
Digestion:
Circulation:
Segmentation:
Appendages:
Nervous:
Habitat:
Respiration:
Excretion:
Locomotion:
Support:
Roundworm
bilateral
pseudocoelomate
mouth and anus
none, fluid in pseudocoel
none
none
dorsal and ventral nerve cord
parasitic
diffusion through body surface
2 lateral tubes
longitudinal muscles, whipping motion
hydrostatic skeleton, pseudocoel
Phylum Rotifera
Rotifers
 Freshwater animals – zooplankton

Phylum Mollusca
Mostly marine but some
are freshwater and
terrestrial
 3 part body

 Muscular foot –
locomotion
 Visceral mass – internal
organs
 Mantle – encloses
visceral mass and may
secrete shell
Digestion – complete
 Circulation – open
(except for cephalopods
that are closed)

Phylum Mollusca

Class Polyplacophora
 “many plated”
 Chitins
Phylum Mollusca

Class Gastropoda
 “stomach foot:
Phylum Mollusca

Class Bivalvia
Phylum Mollusca

Class Cephalopoda
 “Head-foot”
Phylum Mollusca
Class Bivalvia













Animal:
Symmetry:
Body cavity:
Digestion:
Circulation:
Segmentation:
Appendages:
Nervous:
Habitat:
Respiration:
Excretion:
Locomotion:
Support:
Clam
bilateral
coelomate – protostome
complete, filter feeders
open, blue blood, heart, blood vessels
none
none
3 ganglia connected by nerves
aquatic
gills
nephridia in kidney
muscular foot
shell
Clam model
Phylum Mollusca
Class Cephalopoda













Animal:
Symmetry:
Body cavity:
Digestion:
Circulation:
Segmentation:
Appendages:
Nervous:
Habitat:
Respiration:
Excretion:
Locomotion:
Support:
squid
bilateral
coelomate – protostome
complete, beak jaws
closed, 3 hearts
none
8 arms, 2 tentacles
brain of 3 fused ganglia, eye
aquatic
gills
nephridia in kidney
muscular mantle, jet propulsion
shell reduced to pen
What we are doing today:

Phylum Platyhelminthes
 Look at specimens on
benches from all classes
 Planaria model
○ Know following parts: eye
spot, pharynx, ovary,
testis, flame cell, brain
 Planaria – microscope
#29, 30

Phylum Nematoda
 Look at specimens on lab
bench
 Ascaris – microscope # 31,
34

Phylum Rotifera
 Microscope # 46

Phylum Mollusca
 Look at specimens from
all classes
 Learn clam model
○ Refer to page 315 and
316
○ Know following parts:
 Foot, gill, gonad,
intestine, mouth,
stomach, anus,
kidney, mantle