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CAMPBELL
BIOLOGY
TENTH
EDITION
Reece • Urry • Cain • Wasserman • Minorsky • Jackson
40
Basic Principles
of Animal Form
and Function
Lecture Presentation by
Nicole Tunbridge and
Kathleen Fitzpatrick
© 2014 Pearson Education, Inc.
Diverse Forms, Common Challenges
 Anatomy is the biological form of an organism
 Physiology is the biological functions an
organism performs
 The comparative study of animals reveals that
form and function are closely correlated
© 2014 Pearson Education, Inc.
Figure 40.1
© 2014 Pearson Education, Inc.
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
 The body plan of an animal is programmed by the
genome, itself the product of millions of years of
evolution
© 2014 Pearson Education, Inc.
Exchange with the Environment
External environment
Mouth
CO2
O2
Animal
body
Respiratory
system
Heart
Lung tissue (SEM)
Interstitial
fluid
Nutrients
250 µm
In vertebrates, the space
between cells is filled with
interstitial fluid, which
allows for the movement
of material into and out of
cells
Food
Cells
© 2014 Pearson Education, Inc.
Digestive
system
Anus
Unabsorbed
matter (feces)
Excretory
system
Blood vessels in
kidney (SEM)
Metabolic waste
products (nitrogenous waste)
50 µm
Lining of small
intestine (SEM)
100 µm
Circulatory
system
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
 Some organs, such as the pancreas, belong to
more than one organ system
© 2014 Pearson Education, Inc.
Table 40.1
© 2014 Pearson Education, Inc.
Exploring Structure and Function in Animal
Tissues
 Different tissues have different structures that are
suited to their functions
 Tissues are classified into four main categories:
epithelial, connective, muscle, and nervous
© 2014 Pearson Education, Inc.
Figure 40.5a
Epithelial Tissue
Epithelial tissue covers
the outside of the body
and lines the organs and
cavities within the body
It contains cells that are
closely joined
Stratified
squamous
epithelium
Apical
surface
Basal
surface
Cuboidal
epithelium
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Simple columnar
epithelium
Simple
squamous
epithelium
Pseudostratified
columnar
epithelium
Connective Tissue
 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
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 There are three types of connective tissue fiber, all
made of protein
 Collagenous fibers provide strength and flexibility
 Reticular fibers join connective tissue to adjacent
tissues
 Elastic fibers stretch and snap back to their original
length
© 2014 Pearson Education, Inc.
 Connective tissue contains cells, including
 Fibroblasts that secrete the protein of extracellular
fibers
 Macrophages that are involved in the immune
system
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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
 Fibrous connective tissue is found in tendons, which
attach muscles to bones, and ligaments, which connect
bones at joints
 Bone is mineralized and forms the skeleton
 Adipose tissue stores fat for insulation and fuel
 Blood is composed of blood cells and cell fragments in
blood plasma
 Cartilage is a strong and flexible support material
© 2014 Pearson Education, Inc.
Figure 40.5b
Connective Tissue
Blood
Loose connective tissue
Plasma
White
blood
cells
120 µm
55 µm
Collagenous fiber
Cartilage
Elastic fiber
Fibrous connective tissue
Red blood cells
30 µm
100 µm
Chondrocytes
Chondroitin sulfate
Adipose tissue
700 µm
Central
canal
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Osteon
Fat droplets
150 µm
Bone
Nuclei
Muscle Tissue
 Muscle tissue is responsible for nearly all types of
body movement
 Muscle cells consist of filaments of the proteins
actin and myosin, which together enable muscles
to contract
© 2014 Pearson Education, Inc.
Figure 40.5c
Muscle Tissue
Skeletal muscle
Nuclei
Muscle
fiber
Sarcomere
100 µm
Smooth muscle
Nucleus
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Muscle
fibers
Cardiac muscle
25 µm
Nucleus Intercalated
disk
25 µm
Nervous Tissue
 Nervous tissue functions in the receipt,
processing, and transmission of information
 Nervous tissue contains
 Neurons, or nerve cells, that transmit nerve
impulses
 Glial cells, or glia, support cells
© 2014 Pearson Education, Inc.
Figure 40.5d
Nervous Tissue
Glia
Neurons
Neuron:
Dendrites
Cell body
Axons of
neurons
40 µm
Axon
(Fluorescent LM)
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Glia
Blood
vessel
(Confocal LM)
15 µm
Coordination and Control
 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
 A hormone may affect one or more regions
throughout the body
 Hormones are relatively slow acting, but can have
long-lasting effects
© 2014 Pearson Education, Inc.
Figure 40.6
(a) Signaling by hormones
STIMULUS
(b) Signaling by neurons
STIMULUS
Endocrine
cell
Cell body
of neuron
Axon
Nerve
impulse
Hormone
Signal travels
everywhere.
Blood
vessel
Signal travels
to a specific
location.
Nerve
impulse
Axons
Response
Response
© 2014 Pearson Education, Inc.
Concept 40.2: Feedback control maintains the
internal environment in many animals
 Faced with environmental fluctuations, animals
manage their internal environment by either
regulating or conforming
© 2014 Pearson Education, Inc.
Regulating and Conforming
 A regulator uses internal control mechanisms to
control internal change in the face of external
fluctuation
 A conformer allows its internal condition to vary
with certain external changes
© 2014 Pearson Education, Inc.
Figure 40.7
Animals may regulate some environmental
variables while conforming to others, for example
the bass doesn’t regulate its temperature, but does
regulate its internal solute concentration.
40
Body temperature (C)
River otter (temperature regulator)
30
20
Largemouth bass
(temperature conformer)
10
0
0
© 2014 Pearson Education, Inc.
10
20
30
40
Ambient (environmental)
temperature (C)
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
© 2014 Pearson Education, Inc.
Mechanisms of Homeostasis
 Mechanisms of homeostasis moderate changes in
the internal environment
 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
© 2014 Pearson Education, Inc.
Figure 40.8
Thermostat turns
heater off.
Room temperature
Room temperature
increases.
decreases.
ROOM
TEMPERATURE
AT 20C (set point)
Room temperature
increases.
© 2014 Pearson Education, Inc.
Thermostat
turns heater on.
Room temperature
decreases.
Feedback Control in Homeostasis
 Homeostasis in animals relies largely on negative
feedback, which helps to return a variable to a
normal range
 Positive feedback amplifies a stimulus and does
not usually contribute to homeostasis in animals
© 2014 Pearson Education, Inc.
Alterations in Homeostasis
 Set points and normal ranges can change with
age or show cyclic variation
 In animals and plants, a circadian rhythm governs
physiological changes that occur roughly every 24
hours
 Puberty is another example
 A woman’s menstrual cycle is another.
© 2014 Pearson Education, Inc.
Body
temperature
Melatonin
concentration
37.1
60
36.9
40
36.7
20
Melatonin concentration
in blood (pg/mL)
Core body temperature (C)
Figure 40.9
0
36.5
2
6
10
2
6
10
PM
PM
PM
AM
AM
AM
Time of day
(a) Variation in core body temperature and melatonin
concentration in blood
Start of
melatonin secretion
Midnight
Greatest
muscle
strength
Lowest body
temperature
6 PM
6 AM
Most rapid
rise in blood
pressure
Fastest
reaction time
Noon
(b) The human circadian clock
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Lowest
heart rate
Highest risk
of cardiac arrest
Homeostasis can adjust to changes in external
environment, a process called acclimatization
© 2014 Pearson Education, Inc.
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
© 2014 Pearson Education, Inc.
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
© 2014 Pearson Education, Inc.
 Endotherms can maintain a stable body
temperature even in the face of large fluctuations
in environmental temperature
 Endothermy is more energetically expensive than
ectothermy
 In general, ectotherms tolerate greater variation in
internal temperature
© 2014 Pearson Education, Inc.
Figure 40.11
(a) A walrus, an endotherm
(b) A lizard, an ectotherm
© 2014 Pearson Education, Inc.
 Heat regulation in mammals often involves the
integumentary system: skin, hair, and nails
 Five adaptations help animals thermoregulate
 Insulation
 Circulatory adaptations
 Cooling by evaporative heat loss
 Behavioral responses
 Adjusting metabolic heat production
© 2014 Pearson Education, Inc.
Insulation
 Insulation is a major thermoregulatory adaptation
in mammals and birds
 Skin, feathers, fur, and blubber reduce heat flow
between an animal and its environment
 Insulation is especially important in marine
mammals such as whales and walruses
© 2014 Pearson Education, Inc.
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
 In vasoconstriction, blood flow in the skin
decreases, lowering heat loss
© 2014 Pearson Education, Inc.
 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 and
thereby reduce heat loss
© 2014 Pearson Education, Inc.
Figure 40.13
Bottlenose
dolphin
Canada
goose
1
Vein
Artery
1
3
Artery
Vein
35C
33
30
27
20
18
10
9
3
3
2
Key
2
© 2014 Pearson Education, Inc.
Warm blood
Cool blood
Blood flow
Heat transfer
Cooling by Evaporative Heat Loss
 Many types of animals lose heat through
evaporation of water from their skin
 Sweating or bathing moistens the skin, helping to
cool an animal down
 Panting increases the cooling effect in birds and
many mammals
© 2014 Pearson Education, Inc.
Behavioral Responses
 Both endotherms and ectotherms use behavioral
responses to control body temperature
 Some terrestrial invertebrates have postures that
minimize or maximize absorption of solar heat
 Honeybees huddle together during cold weather to
retain heat
© 2014 Pearson Education, Inc.
Adjusting Metabolic Heat Production
 Thermogenesis is the adjustment of metabolic
heat production to maintain body temperature
 Thermogenesis is increased by muscle activity
such as moving or shivering
 Nonshivering thermogenesis takes place when
hormones cause mitochondria to increase their
metabolic activity
 Some ectotherms can also shiver to increase body
temperature
© 2014 Pearson Education, Inc.
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
 Remember the frog from our summer reading?
© 2014 Pearson Education, Inc.
Physiological Thermostats and Fever
 Thermoregulation in mammals is controlled by a
region of the brain called the hypothalamus
 The hypothalamus triggers heat loss or heat
generating mechanisms
 Fever, a response to some infections, reflects an
increase in the normal range for the biological
thermostat
 Some ectothermic organisms seek warmer
environments to increase their body temperature
in response to certain infections
© 2014 Pearson Education, Inc.
Figure 40.17
Thermostat in
hypothalamus
activates cooling
mechanisms.
Response: Blood
vessels in skin dilate.
Response:
Sweat
Body temperature
increases.
Body temperature
decreases.
NORMAL BODY
TEMPERATURE
(approximately
36–38C)
Body temperature
increases.
Body temperature
decreases.
Response: Shivering
Response: Blood
vessels in skin
constrict.
© 2014 Pearson Education, Inc.
Thermostat in
hypothalamus
activates
warming
mechanisms.
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
it relates to an animal’s size, activity, and
environment
© 2014 Pearson Education, Inc.
Energy Allocation and Use
 Organisms can be classified by how they obtain
chemical energy
 Autotrophs, such as plants, harness light energy to
build energy-rich molecules
 Heterotrophs, such as animals, harvest chemical
energy from food
© 2014 Pearson Education, Inc.
Figure 40.18
Organic molecules
in food
External
environment
Animal
body
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
© 2014 Pearson Education, Inc.
Heat
Quantifying Energy Use
 Metabolic rate is the amount of energy an animal
uses in a unit of time
 Metabolic rate can be determined by
 An animal’s heat loss
 The amount of oxygen consumed or carbon dioxide
produced
 Measuring energy content of food consumed and
energy lost in waste products
© 2014 Pearson Education, Inc.
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
 Both rates assume a nongrowing, fasting, and
nonstressed animal
 Ectotherms have much lower metabolic rates than
endotherms of a comparable size
© 2014 Pearson Education, Inc.
Influences on Metabolic Rate
 Metabolic rates are affected by many factors
besides whether an animal is an endotherm or
ectotherm
 Some key factors are age, sex, size, activity,
temperature, and nutrition
© 2014 Pearson Education, Inc.
Size and Metabolic Rate
 Metabolic rate is proportional to body mass to the
power of three quarters (m3/4)
 Smaller animals have higher metabolic rates per
gram than larger animals
 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
© 2014 Pearson Education, Inc.
Figure 40.20
10 3
8
Horse
10 2
Human
Sheep
10
Dog
Cat
1
10
−1
Shrew
7
BMR (L O2/hr•kg)
BMR (L O2/hr) (log scale)
Elephant
Rat
Ground squirrel
Shrew
Mouse
Harvest mouse
10 −2
10 −3
10 −2
10 −1
1
10
5
4
3
2
1
10 2
103
Body mass (kg) (log scale)
(a) Relationship of basal metabolic rate (BMR) to body
size for various mammals
© 2014 Pearson Education, Inc.
6
Harvest mouse
Sheep
Mouse
Elephant
Human
Rat Cat
Ground
Dog
Horse
squirrel
0
10 −3
10 −2
10 −1
1
10
10 2
10 3
Body mass (kg) (log scale)
(b) Relationship of BMR per kilogram of body mass to
body size
Activity and Metabolic Rate
 Activity greatly affects metabolic rate for
endotherms and ectotherms
 In general, the maximum metabolic rate an animal
can sustain is inversely related to the duration of
the activity
© 2014 Pearson Education, Inc.
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
© 2014 Pearson Education, Inc.
Figure 40.21
Relative RNA level (%)
Results
Day
Night
Per2
Bmal1
Euthermia Hibernation
Euthermia Hibernation
100
80
60
40
20
0
© 2014 Pearson Education, Inc.
 Summer torpor, called estivation, enables animals
to survive long periods of high temperatures and
scarce water
 Daily torpor is exhibited by many small mammals
and birds and seems adapted to feeding patterns
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 There are many aspects to the relationship
between structure and function in animals
 There are also some fundamental similarities in
the evolutionary adaptations of plants and animals
© 2014 Pearson Education, Inc.