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Chapter 40
Basic Principles of Animal
Form and Function
PowerPoint® Lecture Presentations for
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
Key concepts
Organization of animal form and function
Homeostasis (balance): temperature, energy
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
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 40-1
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
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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
• Physical laws impose constraints on animal
size and shape
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Physical Constraints on Animal Size and Shape
Fig. 40-2
(a) Tuna
(b) Penguin
(c) Seal
Exchange with the Environment
Fig. 40-3
Mouth
Gastrovascular
cavity
Exchange
Exchange
Exchange
0.15 mm
1.5 mm
(a) Single cell
(b) Two layers of cells
More complex organisms have highly folded internal surfaces for exchanging materials
External environment
CO2
Food
O2
Mouth
Fig. 40-4
Respiratory
system
0.5 cm
50 µm
Animal
body
Lung tissue
Nutrients
Heart
Cells
Circulatory
system
10 µm
Interstitial
fluid
Digestive
system
Excretory
system
Lining of small intestine
Kidney tubules
Anus
Unabsorbed
matter (feces)
Metabolic waste products
(nitrogenous waste)
In vertebrates, the space between cells is filled with interstitial fluid,
which allows for the movement of material into and out of cells
Hierarchical Organization of Body Plans
• Most animals are composed of specialized
cells organized into tissues that have different
functions
• Tissues make up organs, which together make
up organ systems
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Table 40-1
Tissue Structure and Function
• Different tissues have different structures that
are suited to their functions
• Tissues are classified into four main categories:
epithelial, connective, muscle, and nervous
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 40-5a
Epithelial Tissue
Cuboidal
epithelium
Simple
columnar
epithelium
Pseudostratified
ciliated
columnar
epithelium
Stratified
squamous
epithelium
Simple
squamous
epithelium
Fig. 40-5b
Apical surface
Basal surface
Basal lamina
40 µm
Fig. 40-5c
Connective Tissue
Loose
connective
tissue
Chondrocytes
Cartilage
Elastic fiber
Chondroitin
sulfate
Nuclei
Fat droplets
Adipose
tissue
Osteon
150 µm
Fibrous
connective
tissue
30 µm
100 µm
120 µm
Collagenous fiber
White blood cells
Blood
55 µm
700 µm
Bone
Central canal
Plasma
Red blood
cells
Fig. 40-5j
Muscle Tissue
Multiple
nuclei
Muscle fiber
Sarcomere
Skeletal
muscle
Nucleus
100 µm
Intercalated
disk
50 µm
Cardiac muscle
Nucleus
Smooth
muscle
Muscle
fibers
25 µm
Fig. 40-5n
Nervous Tissue
40 µm
Dendrites
Cell body
Glial cells
Axon
Neuron
Axons
Blood vessel
15 µm
Fig. 40-6
Stimulus
Control and coordination
Stimulus
Endocrine
cell
Neuron
Axon
Signal
Hormone
Signal travels
along axon to
a specific
location.
Signal travels
everywhere
via the
bloodstream.
Blood
vessel
Signal
Axons
Response
(a) Signaling by hormones
Response
(b) Signaling by neurons
Fig. 40-7
40
Body temperature (°C)
River otter (temperature regulator)
30
20
Largemouth bass
(temperature conformer)
10
0
10
20
30
40
Ambient (environmental) temperature (ºC)
Homeostasis
• Organisms use homeostasis to maintain a
“steady state” or internal balance regardless of
external environment
• In humans, body temperature, blood pH, and
glucose concentration are each maintained at a
constant level
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 40-8
Response:
Heater
turned
off
sensor
Room
temperature
decreases
Stimulus:
Control center
(thermostat)
reads too hot
Set
point:
20ºC
sensor
Stimulus:
Control center
(thermostat)
reads too cold
Room
temperature
increases
Response:
Heater
turned
on
Feedback Loops in Homeostasis
• 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
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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 non-avian reptiles
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 40-9
(a) A walrus, an endotherm
(b) A lizard, an ectotherm
Variation in Body Temperature
• The body temperature of a poikilotherm varies
with its environment, while that of a
homeotherm is relatively constant
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 40-10
Radiation
Evaporation
Organisms exchange
heat by four physical
processes
Convection
Conduction
• Five general adaptations help animals
thermoregulate:
– Insulation
– Circulatory adaptations
– Cooling by evaporative heat loss
– Behavioral responses
– Adjusting metabolic heat production
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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
Fig. 40-12
Canada goose
Bottlenose
dolphin
Blood flow
Artery Vein
Vein
Artery
35ºC
33º
30º
27º
20º
18º
10º
9º
countercurrent exchange
Fig. 40-13
Some terrestrial
invertebrates have
postures that minimize or
maximize absorption of
solar heat
Fig. 40-14
animals can regulate body temperature by
adjusting their rate of metabolic heat production
O2 consumption (mL O2/hr) per kg
RESULTS
120
100
80
60
40
20
0
0
5
10
15
20
30
25
Contractions per minute
35
Fig. 40-15
PREFLIGHT
Temperature (ºC)
40
PREFLIGHT
WARM-UP
FLIGHT
Thorax
35
30
Abdomen
25
0
2
Time from onset of warm-up (min)
4
Acclimatization in Thermoregulation
• Birds and mammals can vary their insulation to
acclimatize to seasonal temperature changes
• When temperatures are subzero, some
ectotherms produce “antifreeze” compounds to
prevent ice formation in their cells
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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
Fever is the result of a
change to the set point for
a biological thermostat
Homeostasis:
Internal temperature
of 36–38°C
Body temperature
increases; thermostat
shuts off warming
mechanisms.
Decreased body
temperature
Blood vessels in skin
constrict, reducing
heat loss.
Skeletal muscles contract;
shivering generates heat.
Thermostat in
hypothalamus
activates warming
mechanisms.
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
ATP
Biosynthesis
Cellular
work
Heat
Energy lost in
nitrogenous
waste
Heat
Bioenergetics is the
overall flow and
transformation of energy
in an animal
Heat
Quantifying Energy Use
• 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
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 40-18
Minimum Metabolic Rate and Thermoregulation
• Basal metabolic rate (BMR) is the metabolic
rate of an endotherm at rest at a “comfortable”
temperature
• Standard metabolic rate (SMR) is the
metabolic rate of an ectotherm at rest at a
specific temperature
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 40-19
103
Horse
102
Human
Sheep
10
Cat
Dog
1
10–1
Rat
Ground squirrel
Shrew
Mouse
Harvest mouse
10–2
10–3
10–2
10
10–1
1
102
Body mass (kg) (log scale)
103
(a) Relationship of BMR to body size
8
Shrew
7
BMR (L O2/hr) (per kg)
Size and Metabolic Rate
BMR (L O2/hr) (Iog scale)
Elephant
6
5
4
3
2
1
Harvest mouse
Mouse
Rat
Sheep
Cat
Dog
Human Elephant
Horse
Ground squirrel
0
10–3 10–2
102
10–1
1
10
Body mass (kg) (log scale)
103
(b) Relationship of BMR per kilogram of body mass to body size
Fig. 40-20
Energy Budgets
Annual energy expenditure (kcal/hr)
Endotherms
Ectotherm
Reproduction
800,000
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)
0.025-kg female deer mouse
from temperate
North America
8,000
4-kg female eastern
indigo snake
Torpor and Energy Conservation
• Torpor is a physiological state in which activity
is low and metabolism decreases
• Torpor enables animals to save energy while
avoiding difficult and dangerous conditions
• Hibernation is long-term torpor that is an
adaptation to winter cold and food scarcity
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Metabolic rate
(kcal per day)
Fig. 40-21
200
Actual
metabolism
100
0
35
30
Temperature (°C)
Additional metabolism that would be
necessary to stay active in winter
Arousals
Body
temperature
25
20
15
10
5
0
–5
Outside
temperature
Burrow
temperature
–10
–15
June
August
October
December
February
April
• Estivation, or summer torpor, enables animals
to survive long periods of high temperatures
and scarce water supplies
• Daily torpor is exhibited by many small
mammals and birds and seems adapted to
feeding patterns
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings