Download Basic Principles of Animal Form and Function

Chapter 40
Basic Principles of Animal
Form and Function
PowerPoint® Lecture Presentations for
Overview: Diverse Forms, Common Challenges
• Anatomy is the study of the biological form of
an organism
• Physiology is the study of the biological
functions an organism performs
• The comparative study of animals reveals that
form and function are closely correlated
Biology
Eighth Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 40-1
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Concept 40.1: Animal form and function are
correlated at all levels of organization
• Size and shape affect the way an animal
interacts with its environment
• Many different animal body plans have evolved
and are determined by the genome
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Fig. 40-2
Physical Constraints on Animal Size and Shape
• The ability to perform certain actions depends
on an animal’s shape, size, and environment
• Evolutionary convergence reflects different
species’ adaptations to a similar environmental
challenge
(a) Tuna
• Physical laws impose constraints on animal
size and shape
(b) Penguin
Video: Shark Eating Seal
Video: Galá
Galápagos Sea Lion
(c) Seal
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1
Fig. 40-3
Exchange with the Environment
Mouth
• An animal’s size and shape directly affect how
it exchanges energy and materials with its
surroundings
Gastrovascular
cavity
Exchange
Exchange
• Exchange occurs as substances dissolved in
the aqueous medium diffuse and are
transported across the cells’ plasma
membranes
Exchange
• A single-celled protist living in water has a
sufficient surface area of plasma membrane to
service its entire volume of cytoplasm
0.15 mm
1.5 mm
(a) Single cell
Video: Hydra Eating Daphnia
(b) Two layers of cells
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• Multicellular organisms with a sac body plan
have body walls that are only two cells thick,
facilitating diffusion of materials
• More complex organisms have highly folded
internal surfaces for exchanging materials
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Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 40-4
Fig. 40-4a
External environment
CO2 O
Food
2
External environment
CO2
Food
O2
Mouth
Mouth
Animal
body
Animal
body
0.5 cm
Respiratory
system
50 µm
Respiratory
system
Nutrients
Lung tissue
Nutrients
Heart
Circulatory
system
Interstitial
fluid
Digestive
system
Excretory
system
Lining of small intestine
Excretory
system
Kidney tubules
Anus
Unabsorbed
matter (feces)
Cells
Circulatory
system
10 µm
Interstitial
fluid
Digestive
system
Heart
Cells
Metabolic waste products
(nitrogenous waste)
Anus
Unabsorbed
Metabolic waste products
matter (feces) (nitrogenous waste)
2
Fig. 40-4b
Fig. 40-4c
50 µm
0.5 cm
Lung tissue
Lining of small intestine
Fig. 40-4d
10 µm
• In vertebrates, the space between cells is filled
with interstitial fluid, which allows for the
movement of material into and out of cells
• A complex body plan helps an animal in a
variable environment to maintain a relatively
stable internal environment
Kidney tubules
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Hierarchical Organization of Body Plans
Table 40-1
• Most animals are composed of specialized
cells organized into tissues that have different
functions
• Tissues make up organs, which together make
up organ systems
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3
Tissue Structure and Function
Epithelial Tissue
• Different tissues have different structures that
are suited to their functions
• Epithelial tissue covers the outside of the
body and lines the organs and cavities within
the body
• Tissues are classified into four main
categories: epithelial, connective, muscle, and
nervous
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• It contains cells that are closely joined
• The shape of epithelial cells may be cuboidal
(like dice), columnar (like bricks on end), or
squamous (like floor tiles)
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Fig. 40-5a
• The arrangement of epithelial cells may be
simple (single cell layer), stratified (multiple
tiers of cells), or pseudostratified (a single layer
of cells of varying length)
Epithelial Tissue
Cuboidal
epithelium
Simple
columnar
epithelium
Pseudostratified
ciliated
columnar
epithelium
Stratified
squamous
epithelium
Simple
squamous
epithelium
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Fig. 40-5b
Connective Tissue
Apical surface
Basal surface
Basal lamina
• Connective tissue mainly binds and supports
other tissues
• It contains sparsely packed cells scattered
throughout an extracellular matrix
• The matrix consists of fibers in a liquid, jellylike,
or solid foundation
40 µm
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4
• Connective tissue contains cells, including
• There are three types of connective tissue
fiber, all made of protein:
– Fibroblasts that secrete the protein of
extracellular fibers
– Collagenous fibers provide strength and
flexibility
– Macrophages that are involved in the immune
system
– Elastic fibers stretch and snap back to their
original length
– Reticular fibers join connective tissue to
adjacent tissues
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• In vertebrates, the fibers and foundation
combine to form six major types of connective
tissue:
– Loose connective tissue binds epithelia to
underlying tissues and holds organs in place
– Adipose tissue stores fat for insulation
and fuel
– Blood is composed of blood cells and
cell fragments in blood plasma
– Bone is mineralized and forms the
skeleton
– Cartilage is a strong and flexible support
material
– Fibrous connective tissue is found in tendons,
which attach muscles to bones, and
ligaments, which connect bones at joints
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Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 40-5c
Fig. 40-5d
Connective Tissue
Loose
connective
tissue
Chondrocytes
Collagenous fiber
Cartilage
Elastic fiber
Chondroitin
sulfate
Nuclei
Osteon
150 µm
Adipose
tissue
White blood cells
Blood
55 µm
700 µm
Bone
Central canal
Plasma
120 µm
Fat droplets
Fibrous
connective
tissue
30 µm
100 µm
120 µm
Collagenous fiber
Elastic fiber
Loose connective tissue
Red blood
cells
5
Fig. 40-5e
Fig. 40-5f
Osteon
30 µm
700 µm
Nuclei
Central canal
Fibrous connective tissue
Bone
Fig. 40-5g
Fig. 40-5h
Chondrocytes
150 µm
100 µm
Fat droplets
Chondroitin
sulfate
Adipose tissue
Cartilage
Fig. 40-5i
Muscle Tissue
White blood cells
55 µm
• Muscle tissue consists of long cells called
muscle fibers, which contract in response to
nerve signals
Plasma
Blood
Red blood
cells
• It is divided in the vertebrate body into three
types:
– Skeletal muscle, or striated muscle, is
responsible for voluntary movement
– Smooth muscle is responsible for involuntary
body activities
– Cardiac muscle is responsible for contraction
of the heart
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6
Fig. 40-5j
Fig. 40-5k
Muscle Tissue
Multiple
nuclei
Multiple
nuclei
Muscle fiber
Sarcomere
Skeletal
muscle
Nucleus
100 µm
Intercalated
disk
Muscle fiber
50 µm
Cardiac muscle
Sarcomere
Nucleus
Smooth
muscle
100 µm
Muscle
fibers
Skeletal muscle
25 µm
Fig. 40-5l
Fig. 40-5m
Nucleus
Muscle
fibers
Nucleus
25 µm
Smooth muscle
Nervous Tissue
Intercalated
disk
50 µm
Cardiac muscle
Fig. 40-5n
Nervous Tissue
40 µm
• Nervous tissue senses stimuli and transmits
signals throughout the animal
• Nervous tissue contains:
Dendrites
Cell body
Glial cells
Axon
– Neurons, or nerve cells, that transmit nerve
impulses
Neuron
– Glial cells, or glia, that help nourish, insulate,
and replenish neurons
Axons
Blood vessel
15 µm
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Fig. 40-5o
40 µm
Fig. 40-5p
Glial cells
Dendrites
Cell body
Axon
Axons
Blood vessel
Glial cells and axons
15 µm
Neuron
Fig. 40-6
Coordination and Control
Stimulus
Stimulus
Endocrine
cell
Neuron
• Control and coordination within a body depend
on the endocrine system and the nervous
system
• The endocrine system transmits chemical
signals called hormones to receptive cells
throughout the body via blood
Axon
Signal
Hormone
Signal travels
along axon to
a specific
location.
Signal travels
everywhere
via the
bloodstream.
Blood
vessel
Signal
Axons
• A hormone may affect one or more regions
throughout the body
• Hormones are relatively slow acting, but can
have long-lasting effects
Response
(a) Signaling by hormones
Response
(b) Signaling by neurons
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Fig. 40-6a
Stimulus
Endocrine
cell
• The nervous system transmits information
between specific locations
Hormone
Signal travels
everywhere
• The information conveyed depends on a
signal’s pathway, not the type of signal
via the
bloodstream.
Blood
vessel
• Nerve signal transmission is very fast
• Nerve impulses can be received by neurons,
muscle cells, and endocrine cells
Response
(a) Signaling by hormones
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8
Fig. 40-6b
Stimulus
Neuron
Axon
Signal
Signal travels
along axon to
a specific
location.
Concept 40.2: Feedback control loops maintain the
internal environment in many animals
• Animals manage their internal environment by
regulating or conforming to the external
environment
Signal
Axons
Response
(b) Signaling by neurons
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Regulating and Conforming
Fig. 40-7
40
• A regulator uses internal control mechanisms
to moderate internal change in the face of
external, environmental fluctuation
• A conformer allows its internal condition to
vary with certain external changes
Body temperature (°C)
River otter (temperature regulator)
30
20
Largemouth bass
(temperature conformer)
10
0
10
20
30
40
Ambient (environmental) temperature (ºC)
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Homeostasis
Mechanisms of Homeostasis
• Organisms use homeostasis to maintain a
“steady state” or internal balance regardless of
external environment
• Mechanisms of homeostasis moderate
changes in the internal environment
• In humans, body temperature, blood pH, and
glucose concentration are each maintained at a
constant level
• For a given variable, fluctuations above or
below a set point serve as a stimulus; these
are detected by a sensor and trigger a
response
• The response returns the variable to the set
point
Animation: Negative Feedback
Animation: Positive Feedback
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Fig. 40-8
Response:
Heater
turned
off
Room
temperature
decreases
Feedback Loops in Homeostasis
Stimulus:
Control center
(thermostat)
reads too hot
Set
point:
20ºC
Stimulus:
Control center
(thermostat)
reads too cold
Room
temperature
increases
Response:
Heater
turned
on
• The dynamic equilibrium of homeostasis is
maintained by negative feedback, which helps
to return a variable to either a normal range or
a set point
• Most homeostatic control systems function by
negative feedback, where buildup of the end
product shuts the system off
• Positive feedback loops occur in animals, but
do not usually contribute to homeostasis
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Alterations in Homeostasis
• Set points and normal ranges can change with
age or show cyclic variation
• Homeostasis can adjust to changes in external
environment, a process called acclimatization
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Concept 40.3: Homeostatic processes for
thermoregulation involve form, function, and
behavior
• Thermoregulation is the process by which
animals maintain an internal temperature within
a tolerable range
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Endothermy and Ectothermy
• Endothermic animals generate heat by
metabolism; birds and mammals are
endotherms
• Ectothermic animals gain heat from external
sources; ectotherms include most
invertebrates, fishes, amphibians, and nonavian reptiles
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• In general, ectotherms tolerate greater
variation in internal temperature, while
endotherms are active at a greater range of
external temperatures
• Endothermy is more energetically expensive
than ectothermy
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Fig. 40-9
Variation in Body Temperature
• The body temperature of a poikilotherm varies
with its environment, while that of a
homeotherm is relatively constant
(a) A walrus, an endotherm
(b) A lizard, an ectotherm
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Balancing Heat Loss and Gain
Fig. 40-10
Radiation
Evaporation
• Organisms exchange heat by four physical
processes: conduction, convection, radiation,
and evaporation
Convection
Conduction
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Fig. 40-11
• Heat regulation in mammals often involves the
integumentary system: skin, hair, and nails
Hair
Epidermis
Sweat
pore
Muscle
Dermis
Nerve
Sweat
gland
Hypodermis
Adipose tissue
Blood vessels
Oil gland
Hair follicle
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11
Insulation
• Insulation is a major thermoregulatory
adaptation in mammals and birds
• Five general adaptations help animals
thermoregulate:
• Skin, feathers, fur, and blubber reduce heat
flow between an animal and its environment
– Insulation
– Circulatory adaptations
– Cooling by evaporative heat loss
– Behavioral responses
– Adjusting metabolic heat production
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Circulatory Adaptations
• Regulation of blood flow near the body surface
significantly affects thermoregulation
• Many endotherms and some ectotherms can
alter the amount of blood flowing between the
body core and the skin
• In vasodilation, blood flow in the skin
increases, facilitating heat loss
• The arrangement of blood vessels in many
marine mammals and birds allows for
countercurrent exchange
• Countercurrent heat exchangers transfer heat
between fluids flowing in opposite directions
• Countercurrent heat exchangers are an
important mechanism for reducing heat loss
• In vasoconstriction, blood flow in the skin
decreases, lowering heat loss
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Fig. 40-12
Canada goose
Bottlenose
dolphin
• Some bony fishes and sharks also use
countercurrent heat exchanges
Blood flow
Artery
Vein
Vein
Artery
35ºC
33º
30º
27º
20º
18º
10º
9º
• Many endothermic insects have countercurrent
heat exchangers that help maintain a high
temperature in the thorax
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12
Cooling by Evaporative Heat Loss
Behavioral Responses
• Many types of animals lose heat through
evaporation of water in sweat
• Both endotherms and ectotherms use
behavioral responses to control body
temperature
• Panting increases the cooling effect in birds
and many mammals
• Sweating or bathing moistens the skin, helping
to cool an animal down
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• Some terrestrial invertebrates have postures
that minimize or maximize absorption of solar
heat
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Fig. 40-13
Adjusting Metabolic Heat Production
• Some animals can regulate body temperature
by adjusting their rate of metabolic heat
production
• Heat production is increased by muscle activity
such as moving or shivering
• Some ectotherms can also shiver to increase
body temperature
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Fig. 40-14
Fig. 40-15
PREFLIGHT
120
40
100
Temperature (ºC)
O2 consumption (mL O2/hr) per kg
RESULTS
80
60
PREFLIGHT
WARM-UP
FLIGHT
Thorax
35
30
Abdomen
40
20
25
0
0
5
10
15
20
30
25
Contractions per minute
35
0
2
Time from onset of warm-up (min)
4
13
Acclimatization in Thermoregulation
Physiological Thermostats and Fever
• Birds and mammals can vary their insulation to
acclimatize to seasonal temperature changes
• Thermoregulation is controlled by a region of
the brain called the hypothalamus
• When temperatures are subzero, some
ectotherms produce “antifreeze” compounds to
prevent ice formation in their cells
• The hypothalamus triggers heat loss or heat
generating mechanisms
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Fig. 40-16
Sweat glands secrete
sweat, which evaporates,
cooling the body.
Body temperature
decreases;
thermostat
shuts off cooling
mechanisms.
Thermostat in hypothalamus
activates cooling mechanisms.
Blood vessels
in skin dilate:
capillaries fill;
heat radiates
from skin.
Increased body
temperature
Homeostasis:
Internal temperature
of 36–38°C
Body temperature
increases; thermostat
shuts off warming
mechanisms.
• Fever is the result of a change to the set point
for a biological thermostat
Concept 40.4: Energy requirements are related to
animal size, activity, and environment
• Bioenergetics is the overall flow and
transformation of energy in an animal
• It determines how much food an animal needs
and relates to an animal’s size, activity, and
environment
Decreased body
temperature
Blood vessels in skin
constrict, reducing
heat loss.
Skeletal muscles contract;
shivering generates heat.
Thermostat in
hypothalamus
activates warming
mechanisms.
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Energy Allocation and Use
• Animals harvest chemical energy from food
• Energy-containing molecules from food are
usually used to make ATP, which powers
cellular work
• After the needs of staying alive are met,
remaining food molecules can be used in
biosynthesis
• Biosynthesis includes body growth and repair,
synthesis of storage material such as fat, and
production of gametes
Fig. 40-17
External
environment
Animal
body
Organic molecules
in food
Digestion and
absorption
Heat
Energy lost
in feces
Nutrient molecules
in body cells
Carbon
skeletons
Cellular
respiration
Energy lost in
nitrogenous
waste
Heat
ATP
Biosynthesis
Cellular
work
Heat
Heat
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14
Quantifying Energy Use
Fig. 40-18
• Metabolic rate is the amount of energy an
animal uses in a unit of time
• One way to measure it is to determine the
amount of oxygen consumed or carbon dioxide
produced
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Minimum Metabolic Rate and Thermoregulation
Influences on Metabolic Rate
• Basal metabolic rate (BMR) is the metabolic
rate of an endotherm at rest at a “comfortable”
temperature
• Metabolic rates are affected by many factors
besides whether an animal is an endotherm or
ectotherm
• Standard metabolic rate (SMR) is the
metabolic rate of an ectotherm at rest at a
specific temperature
• Two of these factors are size and activity
• Both rates assume a nongrowing, fasting, and
nonstressed animal
• Ectotherms have much lower metabolic rates
than endotherms of a comparable size
Size and Metabolic Rate
• Metabolic rate per gram is inversely related to
body size among similar animals
• Researchers continue to search for the causes
of this relationship
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Fig. 40-19
103
Elephant
BMR (L O2/hr) (Iog scale)
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Horse
102
Human
Sheep
10
Cat
Dog
1
10–1
Rat
Ground squirrel
Shrew
Mouse
Harvest mouse
10–2
10–3
10–2
1
10
10–1
102
Body mass (kg) (log scale)
103
(a) Relationship of BMR to body size
8
7
BMR (L O2/hr) (per kg)
• The higher metabolic rate of smaller animals
leads to a higher oxygen delivery rate,
breathing rate, heart rate, and greater (relative)
blood volume, compared with a larger animal
Shrew
6
5
4
3
Harvest mouse
Mouse
Sheep
Rat Cat
Human Elephant
Dog
Horse
Ground squirrel
0
10–3 10–2
10–1
102
103
1
10
Body mass (kg) (log scale)
2
1
(b) Relationship of BMR per kilogram of body mass to body size
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15
Fig. 40-19a
Fig. 40-19b
103
8
Human
Sheep
10
Cat
Dog
1
10–1
Rat
Ground squirrel
Shrew
Mouse
Harvest mouse
10–2
10–3
10–2
102
1
10–1
10
Body mass (kg) (log scale)
Shrew
7
Horse
102
BMR (L O2/hr) (per kg)
BMR (L O2/hr) (log scale)
Elephant
6
5
4
Harvest mouse
3
Mouse
2
Rat
1
Sheep
Cat
Ground squirrel
0
10–3
103
10–2
Human
Dog
1
10
10–1
102
Body mass (kg) (log scale)
Elephant
Horse
103
(b) Relationship of BMR per kilogram of body mass to body size
(a) Relationship of BMR to body size
Activity and Metabolic Rate
Energy Budgets
• Activity greatly affects metabolic rate for
endotherms and ectotherms
• Different species use energy and materials in
food in different ways, depending on their
environment
• In general, the maximum metabolic rate an
animal can sustain is inversely related to the
duration of the activity
• Use of energy is partitioned to BMR (or SMR),
activity, thermoregulation, growth, and
reproduction
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Fig. 40-20
Fig. 40-20a
Annual energy expenditure (kcal/hr)
Endotherms
Ectotherm
800,000
Reproduction
Thermoregulation
Basal
(standard)
Growth
metabolism
Activity
340,000
4,000
60-kg female human
from temperate climate
4-kg male Adélie penguin
from Antarctica (brooding)
8,000
0.025-kg female deer mouse 4-kg female eastern
from temperate
indigo snake
North America
Annual energy expenditure (kcal/hr)
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Reproduction
800,000
Thermoregulation
Basal
(standard)
metabolism
Growth
Activity
60-kg female human
from temperate climate
16
Fig. 40-20c
Basal
(standard)
metabolism
Reproduction
Thermoregulation
Activity
340,000
Fig. 40-20d
Annual energy expenditure (kcal/yr)
Basal
(standard)
metabolism
Reproduction
Thermoregulation
Activity
4,000
0.025-kg female deer mouse
from temperate
North America
4-kg male Adélie penguin
from Antarctica (brooding)
Basal
(standard)
metabolism
Annual energy expenditure (kcal/yr)
Annual energy expenditure (kcal/yr)
Fig. 40-20b
Torpor and Energy Conservation
Reproduction
• Torpor is a physiological state in which activity
is low and metabolism decreases
Growth
• Torpor enables animals to save energy while
avoiding difficult and dangerous conditions
Activity
• Hibernation is long-term torpor that is an
adaptation to winter cold and food scarcity
8,000
4-kg female eastern
indigo snake
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Metabolic rate
(kcal per day)
Fig. 40-21
200
Actual
metabolism
• Estivation, or summer torpor, enables animals
to survive long periods of high temperatures
and scarce water supplies
100
0
35
30
Temperature (°C)
Additional metabolism that would be
necessary to stay active in winter
Arousals
Body
temperature
• Daily torpor is exhibited by many small
mammals and birds and seems adapted to
feeding patterns
25
20
15
10
5
0
–5
Outside
temperature
Burrow
temperature
–10
–15
June
August
October
December
February
April
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17
Fig. 40-UN1
Fig. 40-UN2
Homeostasis
Response/effector
Stimulus:
Perturbation/stress
Control center
Sensor/receptor
You should now be able to:
1. Distinguish among the following sets of terms:
collagenous, elastic, and reticular fibers;
regulator and conformer; positive and
negative feedback; basal and standard
metabolic rates; torpor, hibernation, estivation,
and daily torpor
2. Relate structure with function and identify
diagrams of the following animal tissues:
epithelial, connective tissue (six types),
muscle tissue (three types), and nervous
tissue
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3. Compare and contrast the nervous and
endocrine systems
4. Define thermoregulation and explain how
endotherms and ectotherms manage their
heat budgets
5. Describe how a countercurrent heat
exchanger may function to retain heat within
an animal body
6. Define bioenergetics and biosynthesis
7. Define metabolic rate and explain how it can
be determined for animals
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18