Transcript Slide 1

Lecture #8 – Introduction to Animal
Structure and Function
Images – the two most beautiful cats in the world,
currently, as kittens and grownups
1
Key Concepts
• What separates animals from other
organisms?
• Introduction to structure and function
relationships – the implications of being
multicellular
• Hierarchical organization in animals
• Tissues
• Organ systems
• Bioenergetics and metabolic rates
2
What do all organisms have to do
to make a living???
???
3
What do organisms have to do to
make a living???
4
What makes an animal an animal?
???
5
What makes an animal an animal?
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Structure and Function of Animal
Systems
• Focus on human biology, but will use
comparative approach
Comparisons between animals of differing
levels of complexity
• We will correlate structure with function, at
all levels of organization
Important theme in biology
• Start with intro to basic principles
Then discussions of various organ systems
7
Critical Thinking
• Life has been on this
planet for 3½ billion
years!
• Until about 700 million
years ago, all organisms
were______________?
Table - the geological
time scale
8
It’s always fun to
study the
geological time
scale – it reveals
the history of life
on earth
What happened here???
9
Critical Thinking
• Life has been on this planet for 3½ billion
years!
• Until about 700 million years ago, all
organisms were
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Multi-cellularity imposes limitations, too
• In most multi-cellular organisms, not every
cell is in contact with the external
environment
Multi-cellular organisms develop complex
morphologies that reflect their environment
Multi-cellular organisms develop complex
mechanisms for resource/waste exchange with
their environment
We saw these phenomena with plants –
animals do the same thing
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Critical Thinking
• Terrestrial plants use a tight epidermis and
a waxy cuticle to retain water
• What is the analogous structure in
terrestrial animals???
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Critical Thinking
• Terrestrial plants use a tight epidermis and
a waxy cuticle to retain water
• What is the analogous structure in
terrestrial animals???
13
Critical Thinking
• Most animals (even many aquatic animals)
urinate. Why???
• Do plants pee???
14
Critical Thinking
• Most animals (even many aquatic animals)
urinate. Why???
• Do plants pee???
15
Critical Thinking
• Most animals (even many aquatic animals)
urinate. Why???
• Do plants pee???
16
Constraints On Size And Shape:
The physical environment affects animal
evolution – as it does with all organisms
• Simple physics
Flight, soil burrowing,
swimming for speed…
Images - convergent
evolution of spindleshaped swimmers
• The physical environment
Dense water or soil, thin air
• Often leads to convergent
evolution of shape
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Constraints On Size And Shape:
The necessity of exchange with the
environment affects animal evolution….
• Resource/waste exchange
with the environment
• Diffusion at the surface was
characteristic of the earliest
animals
Limits size
Limits shape to thin, flat, open
Limits complexity
Mostly quite simple animals
Diagram - 2 tissue
layers in Cnidarians
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Most animals have much more
complex exchange systems
• Exchange occurs at internal epithelia
• Huge surface area is characteristic
• Fun factoids from humans:
 Lungs have 100 m2 of surface area (about ½ as big as
room)
 Small intestine has surface area of a tennis court
 80 km of tubules in a single kidney
 100,000 km of blood vessels = almost 3x circumference
of the earth
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Critical Thinking
• How on earth do such large surface areas
fit into our bodies???
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Critical Thinking
• How on earth do such large surface areas
fit into our bodies???
Micrographs - lung and intestinal tissues
Small Intestine Tissue
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Exchange with environment is not
direct for most animals
• Body is covered with waterproof surface
• Complex organ systems exchange
materials
• Organ systems are linked together, but not
usually directly
• Most organ systems are separated by
interstitial fluid = a water-based solution
that surrounds all cells in the animal body
• Transport occurs through the interstitial
fluid
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Indirect exchange
between organism
and environment,
and between
organ systems
Diagram - organization of organ
systems showing indirect exchange
through the interstitial fluid; same
diagram on #29
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Critical Thinking
• Do nutrients leap from our breakfast cereal
to our cells???
• Why do animals need nutrients anyways???
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Critical Thinking
• Do nutrients leap from our breakfast cereal
to our cells???
• Why do animals need nutrients anyways???
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Critical Thinking
• Do nutrients leap from our breakfast cereal
to our cells???
• Why do animals need nutrients anyways???
26
Exchange with environment is not
direct for complex animals
• Body is covered with waterproof surface
• Complex organ systems exchange
materials
• Organ systems are linked together, but not
usually directly
• Organ systems are separated by
interstitial fluid = a water-based solution
that surrounds all cells in the animal body
• Transport occurs through the interstitial
fluid
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Indirect exchange
between organ
systems occurs
via the interstitial
fluid
one big exception:
the Malphigian
excretory tubules
in insects are
directly connected
to the digestive
tract
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All complex
organisms have
a hierarchical
organization
•
•
•
•
•
Diagram - cells - organism in a zebra
Cells
Tissues
Organs
Organ systems
Organism
Form Reflects Function!!!
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Critical Thinking
• Think of your heart, or this zebra’s – how
are structure and function related???
30
Critical Thinking
• Think of your heart, or this zebra’s – how
are structure and function related???
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Form and function are correlated
from cells  whole organism
• We learned about cells in 111….
Cells
Tissues
Organs
Organ systems
Organism
32
Four major tissue types –
read more in text
Diagram – tissue types
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Epithelial Tissues
• Sheets of cells that cover the body surfaces
and line many of the internal organs
• Base of epithelial tissue is attached to a
basement membrane
• The free (exposed) surface has cells that
are either cuboidal, columnar or squamous
(tile shaped)
• Shape reflects function!
• Some epithelia waterproof, some leak,
some secrete, some slough off….
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Epithelial
tissues
Diagram – sub-types of epithelial tissues
Which do you
think are
waterproof???
Which
leaky???
Which
secrete???
Which slough
off???
35
Connective Tissues
• Cells held in a fibrous or fluid extra-cellular
matrix
Matrix generally secreted by the cells
• Many types and sub-types of connective
tissue
Loose – bind and shape
Adipose – store fat
Fibrous – strong connections
Cartilage – cushions
Bone – support system
Blood – connects tissues to resources
36
Critical Thinking
• What makes the “bones” of plants???
37
Critical Thinking
• What makes the “bones” of plants???
38
Critical Thinking
• How about the blood???
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Critical Thinking
• What makes the “blood” of plants???
40
Muscle Tissue
• Composed of cells that can contract
• Skeletal = enable movement, attached to
bones by tendons
Voluntary = under conscious nervous system
control
• Cardiac = forms the heart
Involuntary
• Smooth or visceral = surround the digestive
tract, other organs
Involuntary
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Nervous Tissue
• Transmits messages from one part of body
to another
• Nerve cells have a central cell body +
appendages that carry messages toward
or away from the cell (dendrites/axons)
• Appendages may be a meter long in
humans!
42
Critical Thinking
• Do all animal tissue types have directly
analogous tissue types in plants???
• Epithelial???
• Connective???
• Muscle???
• Nervous???
43
Critical Thinking
• Do all animal tissue types have directly
analogous tissue types in plants???
• Epithelial –
• Connective –
• Muscle –
• Nervous –
44
Organs
• Composed of two or more types of tissues
organized into a functional unit
• Tissues are often in layers, or they may be
integrated throughout the organ
Stomach has layers of epithelial, connective,
muscle, connective
Skin has layers of epithelial, connective,
muscle
All tissues have blood vessels and nerve
tissues integrated
45
Most animals have body cavities
• These are fluid filled spaces that cushion
and suspend organs
• Sometimes they also give the body shape
• In vertebrates, many organs are held in
place in the body cavity by layers of
connective tissues (mesenteries) and
sheets of muscle (diaphragm)
Diagram – body cavities
46
Organ Systems:
groups of related organs that maintain various
body functions
• Complex organ systems are present in all
higher animals
• All organ systems are interdependent
Functions are coordinated (ex: digestive +
vascular)
• All systems work together to maintain
homeostasis (~constant internal conditions,
more on this later)
47
Organ Systems:
most complex animals have 11 major organ
systems – image search for a table like this one
Table – all the organ systems found in a complex animal
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Diagrams – closeups of the major organ
systems; similar diagrams on next 4 slides
Digestive
Circulatory
49
Respiratory
Immune
50
Excretory
Endocrine
51
Reproductive
Nervous
52
Skeletal and
Integumentary
Muscular
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Organ systems
are integrated in
both structure
and function to
produce the
whole organism
Diagram – summary of organ systems
54
Bioenergetic Principles Regulate
Organism Activity
• Bioenergetics: the flow of energy through
the animal
Controlled by energy sources vs. energy uses
(food intake vs. metabolism)
• Metabolic rates vary based on size, activity
levels, homeostasis strategy and
thermoregulation strategy
Important selection pressures include the
physical environment and interactions with
other organisms
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Energy
management:
Diagram – bioenergetics in an organism
food supplies
energy to fund
metabolism,
maintain
homeostasis,
and support
activity
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Influences on Metabolic Rate
• Body size
Inverse relationship between size and
metabolic rate per unit mass
Evidence is clear; explanation is unclear
• Activity level
• Homeostasis strategy
It “costs” more to regulate
• Thermoregulation strategy
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Influences on Metabolic Rate
• Body size
Inverse relationship between size and
metabolic rate per unit mass
Evidence is clear; explanation is unclear
• Activity level
• Homeostasis strategy
It “costs” more to regulate
• Thermoregulation strategy
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Homeostasis
• Maintenance of constant internal
conditions (actually, within a range of
tolerance)
• Various control systems regulate
temperature, salt concentrations, water
content, pH, blood sugar, etc
• Most control systems rely on negative
feedback loops = the results of a process
inhibit that process
process is self limiting
59
Most organisms regulate at least some
components of their internal environment
Diagram – homeostasis
60
Homeostasis
• Maintenance of constant internal
conditions (actually, within a range of
tolerance)
• Various control systems regulate
temperature, salt concentrations, water
content, pH, blood sugar, etc
• Most control systems rely on negative
feedback loops = the results of a process
inhibit that process
Process is self limiting
61
Feedback Loops:
thermostats and
furnaces are a
non-living
example
Diagram – a mechanical
representation of a negative
feedback loop
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Many similar strategies for regulation of
blood chemistry, blood sugar, body
temperature, etc etc etc
Diagrams – representations of
biological negative feedback
loops
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Homeostasis is dynamic….
• All feedback loops are constantly monitored
and levels are fluctuating within range
• Not all animals maintain stable internal
conditions
Regulators expend metabolic energy to
maintain stability
Conformers don’t – internal values vary with
external conditions
Some animals regulate some conditions,
conform to others
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Influences on Metabolic Rate
• Body size
Inverse relationship between size and
metabolic rate per unit mass
Evidence is clear; explanation is unclear
• Activity level
• Homeostasis strategy
It “costs” more to regulate
• Thermoregulation strategy
65
Thermoregulation
• All biochemical processes are sensitive to
temperature
• Extreme temperatures can denature
proteins or alter membrane function
• Animals regulate their internal temperature
to maintain metabolic function
• Two main strategies have emerged
Ecothermy
Endothermy
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Thermoregulation
• Ectothermic animals gain heat from the
surrounding environment
• Most invertebrates, fishes, amphibians
and reptiles
Low metabolic rate when cold
Not always able to be active
Behavior is often used to regulate body
temperature
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Critical Thinking
• Are ectothermic animals cold blooded???
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Critical Thinking
• Are ectothermic
animals cold
blooded???
Graph – body temp vs. environmental
temp in ectotherms vs. endotherms
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Critical Thinking
• What are the costs and benefits of
ectothermy???
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Critical Thinking
• What are the costs and benefits of
ectothermy???
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Thermoregulation
• Endothermic animals use energy to
maintain a constant body temperature
• Primarily mammals and birds
High metabolic rate generates waste heat that
keeps the body warm
Most endotherms also gain some heat from
their surroundings or behaviors
Some endotherms vary body temperature by
season or time of day (hibernation, estivation,
diurnation)
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Critical Thinking
• What are the costs and benefits of
endothermy???
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Critical Thinking
• What are the costs and benefits of
endothermy???
74
Most endotherms are terrestrial
• Moving on land requires more energy than
moving in water (water supports)
• Land T fluctuates more than water T (high
heat capacity of H2O)
• The development of endothermy was an
important adaptation to the colonization of
land
• Many terrestrial animals are ectothermic,
but few aquatic animals are endothermic
75
Always
active
Graph – body temp vs. environmental
temp in ectotherms vs. endotherms
Slow
when it’s
cold
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Both endo’s and ecto’s have many
strategies to regulate body temperature
• Insulation
• Adjusting the rate of heat exchange with
the environment
• Evaporative cooling
• Behavior
• Adjusting metabolic rate
77
Diagram – adipose tissue as insulation
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Many strategies to regulate body
temperature
• Insulation
• Adjusting the rate of heat exchange with
the environment
• Evaporative cooling
• Behavior
• Adjusting metabolic rate
79
Adjusting the rate of heat exchange
with the environment
• Constriction or dilation of surface blood
vessels
• Raising of fur or feathers
• Fat accumulation
• Countercurrent heat exchange
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Critical Thinking
• How would changing blood vessel diameter
change the rate of heat exchange???
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Critical Thinking
• How would changing blood vessel diameter
change the rate of heat exchange???
82
Adjusting the rate of heat exchange
with the environment
• Constriction or dilation of surface blood
vessels
• Raising of fur or feathers
• Fat accumulation
• Countercurrent heat exchange
83
Critical Thinking
• How would raising the fur or feathers
change the rate of heat exchange???
84
Critical Thinking
• Why would raising the fur or feathers
change the rate of heat exchange???
Image – fluffed bird
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Adjusting the rate of heat exchange
with the environment
• Constriction or dilation of surface blood
vessels
• Raising of fur or feathers
• Fat accumulation
• Countercurrent heat exchange
86
Countercurrent Exchange: arterial blood is warmer
(comes from body core); warms adjacent venous
blood in extremities
Diagram – countercurrent blood
flow in bird’s leg and dolphin’s fin
87
Adjusting the rate of heat exchange
with the environment
• Some ectotherm fishes
maintain higher
temperatures in their
deep swimming muscles
with a heat exchanging
pattern of blood flow
Increases aerobic
respiration (thus ATP
production) in those
muscles
Partial endotherms
Diagram – countercurrent flow
in deep muscles of fish
88
Many strategies to regulate body
temperature
• Insulation
• Adjusting the rate of heat exchange with
the environment
• Evaporative cooling
• Behavior
• Adjusting metabolic rate
89
Sweating, panting,
wetting….often
linked to
behaviors….
Images – animals panting and spraying
90
Many strategies to regulate body
temperature
• Insulation
• Adjusting the rate of heat exchange with
the environment
• Evaporative cooling
• Behavior
• Adjusting metabolic rate
91
Behavior
• Moving to shade/sun
• Moving into/out of water
• Restricting activity to
night/day
• Regulating body posture to
manage solar exposure
• Migrating
• Social behavior to share
heat (bees)
Image – dragonfly
positioned for
minimum solar
exposure
92
Many strategies to regulate body
temperature
• Insulation
• Adjusting the rate of heat exchange with
the environment
• Evaporative cooling
• Behavior
• Adjusting metabolic rate
93
Adjusting metabolic rate
• Increases or decreases in muscular activity
(shivering, active motion)
• Acclimation – many animals adjust to temperature
changes throughout the seasons by changing
enzyme type and quantity, altering lipids to keep
membranes fluid
• Torpor – some animals react to predictable
temperature and food supply fluctuations by
entering a state of reduced metabolism
(hibernation, etc)
 Daylength is the likely trigger
94
Graph – change in a moth’s thorax
temperature with pre-flight shivering
95
Adjusting metabolic rate
• Increases or decreases in muscular activity
(shivering, active motion)
• Acclimation – many animals adjust to temperature
changes throughout the seasons by changing
enzyme type and quantity, altering lipids to keep
membranes fluid
• Torpor – some animals react to predictable
temperature and food supply fluctuations by
entering a state of reduced metabolism
(hibernation, etc)
 Daylength is the likely trigger for seasonal torpor
96
REVIEW: Both endo’s and ecto’s have
many strategies to regulate body
temperature
• Insulation
• Adjusting the rate of heat exchange with
the environment
• Evaporative cooling
• Behavior
• Adjusting metabolic rate
97
REVIEW: Key Concepts
• What separates animals from other
organisms?
• Introduction to structure and function
relationships – the implications of being
multicellular
• Hierarchical organization in animals
• Tissues
• Organ systems
• Bioenergetics and metabolic rates
98