1. Ch. 40: Basic Principles of Animal Form and Function

2. 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. Size and shape affect the way an animal interacts with its environment
A complex body plan helps an animal living in a variable environment to maintain
a relatively stable
internal environment

3. Evolution of Animal Size and Shape
Physical laws govern strength, diffusion, movement, and heat exchange
Materials such as nutrients, waste products, and gases must be exchanged across the cell membranes of animal cells. Rate of exchange is proportional to a cell’s surface area while amount of exchange material is proportional to a cell’s volume
Properties of water limit possible shapes for fast swimming animals
As animals increase in size, thicker skeletons are required for support
Convergent evolution often results in similar adaptations of diverse organisms facing the same challenge

4. Seal Penguin Tuna Figure 40.2
Figure 40.2 Convergent evolution in fast swimmers
Tuna

5. More complex organisms are composed of compact masses of cells with complex internal organization
Evolutionary adaptations such as specialized, extensively branched or folded structures, enable sufficient exchange with the environment
250 µm
100 µm
Lung tissue (SEM)
Lining of small
intestine (SEM)

6. Hierarchical Organization of Body Plans
Most animals are composed of specialized cells organized into tissues that have different functions
In vertebrates, the space between cells is filled with interstitial fluid, which allows for the movement of material into and out of cells
Tissues make up organs, which together make up organ systems. (Some organs, such as the pancreas, belong to more than one organ system)
Organ systems carry out the major body functions of most animals.
The efforts of all systems must be coordinated for the animal to survive. Any organism, whether single-celled or an assembly of organ systems, is a coordinated living whole greater than the sum of its parts.

7. Table 40.1a
Table 40.1a Organ systems in mammals (part 1: main components)

8. Table 40.1b
Table 40.1b Organ systems in mammals (part 2: main functions)

9. 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

10. Epithelial Tissue
Epithelial tissue covers the outside of the body and lines the organs and cavities within the body
It also makes up the tissue of many/most glands, both endocrine and exocrine
It contains cells that are closely joined with many tight junctions
One surface of the epithelial tissue is free, the other is attached to a basal layer
The shape of epithelial cells may be cuboidal (like dice), columnar (like bricks on end), or squamous (like floor tiles)
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)

11. Epithelial Tissue Stratified squamous epithelium Cuboidal
Figure 40.5a
Epithelial Tissue
Stratified
squamous
epithelium
Apical
surface
Basal
surface
Figure 40.5a Exploring structure and function in animal tissues (part 1: epithelial)
Cuboidal
epithelium
Pseudostratified
columnar
epithelium
Simple columnar
epithelium
Simple
squamous
epithelium

12. Polarity of epithelia Apical surface Lumen Basal surface 10 µm
Figure 40.5aa
Lumen
Apical surface
Basal surface
Figure 40.5aa Exploring structure and function in animal tissues (part 1a: epithelial polarity)
10 µm
Polarity of epithelia

13. Connective tissue mainly binds and supports other tissues
It contains sparsely packed cells scattered throughout an extracellular matrix
Connective tissue contains cells, including
Fibroblasts that secrete the protein of extracellular fibers
Macrophages that are involved in the immune system
The matrix consists of fibers in a liquid, jellylike, or solid foundation

14. There are three types of connective tissue fiber, all made of protein:
Collagenous fibers (protein = collagen) : non- elastic, provide strength and flexibility
Elastic fibers (protein = elastin) stretch and snap back to their original length
Reticular fibers (protein = collagen) continuous with collaginous fibers, reticular fibers are thin and branched and join connective tissue to adjacent tissues

15. 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. It is dense wioth lots of collagenous fibers arranged in bundles.
Adipose tissue stores fat for insulation and fuel
Cartilage is a strong and flexible support material. The cells of cartilage are known as chondrocytes. Cartilage has an abundance of collagen fibers embedded in a rubbery matrix of chondroitin sulfate

16. Blood
Blood is composed of blood cells and cell fragments in blood plasma
Blood functions differently from other connective tissues, but it does have an extensive extracellular matrix.
The matrix is a liquid called plasma, consisting of water, salts, and a variety of dissolved proteins.
Suspended in the plasma are erythrocytes (red blood cells) that carry oxygen, leukocytes (white blood cells) that function in defense against viruses, bacteria, and other invaders, and cell fragments called platelets which aid in blood clotting.

17. Bone Bone is mineralized and forms the skeleton
Bone-forming cells called osteoblasts deposit a matrix of collagen.
Calcium, magnesium, and phosphate ions combine and harden within the matrix into the mineral hydroxyapatite.
The combination of hard mineral and flexible collagen makes bone harder than cartilage without being brittle.
The microscopic structure of hard mammalian bones consists of repeating units called osteons. Each osteon has concentric layers of somewhat spaced cells surrounded by a mineralized matrix. This matrix is deposited around a central Haversian canal containing blood vessels and nerves that service the bone.

18. Connective Tissue Blood Loose connective tissue Cartilage
Figure 40.5b
Connective Tissue
Blood
Loose connective tissue
Plasma
Collagenous fiber
White
blood
cells
55 µm
120 µm
Red blood cells
Cartilage
Elastic fiber
Fibrous connective tissue
Chondrocytes
100 µm
30 µm
Figure 40.5b Exploring structure and function in animal tissues (part 2: connective)
Chondroitin sulfate
Bone
Adipose tissue
Nuclei
Central
canal
Fat droplets
700 µm
150 µm
Osteon

19. Muscle Tissue
Muscle tissue is responsible for nearly all types of body movement
Muscle tissue consists of long cells called muscle fibers, which contract in response to nerve signals
Arranged in parallel within the cytoplasm of muscle fibers are large numbers of myofibrils made of the contractile proteins actin and myosin which slide past each other to contract the muscle.
Muscle is the most abundant tissue in most animals and muscle contraction accounts for most of the energy-consuming work in active animals
Muscle is divided in the vertebrate body into 3 types

20. Skeletal Muscle
Skeletal muscle, or striated muscle, is responsible for voluntary movement. It attaches at movable joints.
Skeletal muscle is also called striated muscle because the arrangement of contractile units, or sarcomeres, gives the cells a striped (striated) appearance under the microscope.
Skeletal muscle consists of bundles of long cylindrical cells called fibers.
Each fiber is a bundle of strands called myofibrils.
Skeletal muscle
Nuclei
Muscle
fiber
Sarcomere
100 µm

21. Smooth muscle
Smooth muscle is responsible for involuntary body activities,
It is found in the walls of the digestive tract, urinary bladder, arteries, and other internal organs.
The cells are spindle-shaped.
They contract more slowly than skeletal muscles but can remain contracted longer.
Controlled by different kinds of
nerves than those controlling
skeletal muscles, smooth muscles
are responsible for involuntary
body activities. These include
churning of the stomach and
constriction of arteries.
Smooth muscle
Nucleus
Muscle fibers
25 µm

22. Cardiac Muscle
Cardiac muscle is responsible for contraction of the heart.
It is also striated and characterized by intercalated discs.
Cardiac muscle fibers branch and interconnect via intercalated disks, which relay signals from cell to cell during a heartbeat.
Individual cardiac muscle cells are capable of independent contraction.
Cardiac muscle
Nucleus
Intercalated disk
25 µm

23. Muscle Tissue Skeletal muscle Smooth muscle Cardiac muscle Nuclei
Figure 40.5c
Muscle Tissue
Skeletal muscle
Nuclei
Muscle
fiber
Sarcomere
100 µm
Smooth muscle
Cardiac muscle
Figure 40.5c Exploring structure and function in animal tissues (part 3: muscle)
Nucleus
Muscle
fibers
25 µm
Nucleus
Intercalated
disk
25 µm

24. Video: Cardiac Muscle Contraction

25. Nervous tissue contains
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

26. Nervous Tissue Neurons Glia 15 µm Glia Neuron: Dendrites Cell body
Figure 40.5d
Nervous Tissue
Neurons
Glia
15 µm
Glia
Neuron:
Dendrites
Cell body
Axons of
neurons
Axon
40 µm
Figure 40.5d Exploring structure and function in animal tissues (part 4: nervous)
Blood
vessel
(Fluorescent LM)
(Confocal LM)

27. Neurons (Fluorescent LM) Neuron: Dendrites Cell body Axon 40 µm
Figure 40.5da
Neurons
Neuron:
Dendrites
Cell body
Axon
Figure 40.5da Exploring structure and function in animal tissues (part 4a: neurons)
40 µm
(Fluorescent LM)

28. Glia 15 µm Glia Axons of neurons Blood vessel (Confocal LM)
Figure 40.5db
Glia
15 µm
Glia
Axons of
neurons
Figure 40.5db Exploring structure and function in animal tissues (part 4b: glia)
Blood
vessel
(Confocal LM)

29. 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

30. Figure 40.6 Signaling in the endocrine and nervous systems Axons
(a) Signaling by hormones
(b) Signaling by neurons
STIMULUS
STIMULUS
Endocrine
cell
Cell body
of neuron
Nerve
impulse
Axon
Hormone
Signal travels
everywhere.
Signal travels
to a specific
location.
Blood
vessel
Nerve
impulse
Figure 40.6 Signaling in the endocrine and nervous systems
Axons
Response
Response

31. Endocrine cell Cell body of neuron Nerve Axon impulse Hormone
Figure 40.6a
(a) Signaling by hormones
(b) Signaling by neurons
STIMULUS
STIMULUS
Endocrine
cell
Cell body
of neuron
Nerve
impulse
Axon
Hormone
Figure 40.6a Signaling in the endocrine and nervous systems (part 1: stimulus)
Signal travels
everywhere.
Signal travels
to a specific
location.
Blood
vessel

32. Blood Nerve vessel impulse Axons Response Response
Figure 40.6b
(a) Signaling by hormones
(b) Signaling by neurons
Blood
vessel
Nerve
impulse
Axons
Figure 40.6b Signaling in the endocrine and nervous systems (part 2: response)
Response
Response

33. The nervous system transmits information between specific locations
The information conveyed depends on a signal’s pathway, not the type of signal
Nerve signal transmission is very fast

34. 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

35. 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
Animals may regulate some environmental variables while conforming to others

36. (temperature conformer) Ambient (environmental)
Figure 40.7 40
River otter (temperature regulator) 30
Body temperature (C) 20
Largemouth bass
(temperature conformer) 10
Figure 40.7 The relationship between body and environmental temperatures in an aquatic temperature regulator and an aquatic temperature conformer 10 20 30 40
Ambient (environmental)
temperature (C)

37. (temperature conformer) Ambient (environmental)
Figure 40.7a 40
River otter (temperature regulator) 30
Body temperature (C) 20
Largemouth bass
(temperature conformer) 10
Figure 40.7a The relationship between body and environmental temperatures in an aquatic temperature regulator and an aquatic temperature conformer (part 1: graph) 10 20 30 40
Ambient (environmental)
temperature (C)

38. Figure 40.7b
Figure 40.7b The relationship between body and environmental temperatures in an aquatic temperature regulator and an aquatic temperature conformer (part 2: river otter)

39. Figure 40.7c
Figure 40.7c The relationship between body and environmental temperatures in an aquatic temperature regulator and an aquatic temperature conformer (part 3: largemouth bass)

40. 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

41. 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

42. Thermostat turns heater off. Room temperature increases.
Figure 40.8
Thermostat turns
heater off.
Room temperature
increases.
Room temperature
decreases.
ROOM
TEMPERATURE
AT 20C (set point)
Figure 40.8 A nonliving example of temperature regulation: control of room temperature
Room temperature
increases.
Room temperature
decreases.
Thermostat
turns heater on.

43. Animation: Negative Feedback

44. Animation: Positive Feedback

45. 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

46. 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

47. Melatonin concentration Core body temperature (C)
Figure 40.9
Body
temperature
Melatonin
concentration
37.1 60
Melatonin concentration
in blood (pg/mL)
Core body temperature (C)
36.9 40
36.7 20
36.5 2 PM 6 PM 10 PM 2 AM 6 AM 10 AM
Time of day
(a)
Variation in core body temperature and melatonin
concentration in blood
Start of
melatonin secretion
Midnight
Lowest
heart rate
Greatest
muscle
strength
Figure 40.9 Human circadian rhythm
Lowest body
temperature
6 PM
6 AM
Most rapid
rise in blood
pressure
Fastest
reaction time
Highest risk
of cardiac arrest
Noon
(b) The human circadian clock

48. Melatonin concentration Core body temperature (C)
Figure 40.9a
Body
temperature
Melatonin
concentration
37.1 60
Melatonin concentration
in blood (pg/mL)
Core body temperature (C)
36.9 40
36.7 20
36.5
Figure 40.9a Human circadian rhythm (part 1: graph) 2 PM 6 PM 10 PM 2 AM 6 AM 10 AM
Time of day
Variation in core body temperature and melatonin
concentration in blood
(a)

49. (b) The human circadian clock
Figure 40.9b
Midnight
Start of
melatonin secretion
Lowest
heart rate
Greatest
muscle
strength
Lowest body
temperature
6 PM
6 AM
Most rapid
rise in blood
pressure
Fastest
reaction time
Figure 40.9b Human circadian rhythm (part 2: clock)
Highest risk
of cardiac arrest
Noon
(b) The human circadian clock

50. Homeostasis can adjust to changes in external environment, a process called acclimatization

51. Figure 40.10
Figure Acclimatization by mountain climbers in the Himalayas

52. 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

53. 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

54. 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

55. (a) A walrus, an endotherm
Figure 40.11
(a) A walrus, an endotherm
Figure Thermoregulation by internal or external sources of heat
(b) A lizard, an ectotherm

56. (a) A walrus, an endotherm
Figure 40.11a
Figure 40.11a Thermoregulation by internal or external sources of heat (part 1: endotherm)
(a) A walrus, an endotherm

57. (b) A lizard, an ectotherm
Figure 40.11b
Figure 40.11b Thermoregulation by internal or external sources of heat (part 2: ectotherm)
(b) A lizard, an ectotherm

58. Variation in Body Temperature
The body temperature of a poikilotherm varies with its environment
The body temperature of a homeotherm is relatively constant
The relationship between heat source and body temperature is not fixed (that is, not all poikilotherms are ectotherms)

59. Balancing Heat Loss and Gain
Organisms exchange heat by four physical processes: radiation, evaporation, convection, and conduction

60. Radiation Evaporation Convection Conduction Figure 40.12
Figure Heat exchange between an organism and its environment
Convection
Conduction

61. Five adaptations help animals thermoregulate
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

62. 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

63. 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

64. 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

65. Bottlenose dolphin Canada goose 1 Vein 1 3 Artery Artery Vein 3 3 35C
Figure 40.13
Bottlenose
dolphin
Canada
goose 1
Vein 1 3
Artery
Artery
Vein 3 3
35C
33
30
27
Figure Countercurrent heat exchangers
20
18 2
10 9
Key
Warm blood
Blood flow 2
Cool blood
Heat transfer

66. Some bony fishes and sharks also use countercurrent heat exchanges
Many endothermic insects have countercurrent heat exchangers that help maintain a high temperature in the thorax

67. 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

68. 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

69. Figure 40.14
Figure Thermoregulatory behavior in a dragonfly

70. 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

71. Time from onset of warm-up (min)
Figure 40.15
PREFLIGHT
PREFLIGHT
WARM-UP
FLIGHT 40
Thorax
Thorax 35
Temperature (C)
Abdomen 30
Abdomen
Figure Preflight warm-up in the hawkmoth 25 2 4
Time from onset of warm-up (min)

72. O2 consumption (mL O2/hr•kg)
Figure 40.16
Results
120
100 80
O2 consumption (mL O2/hr•kg) 60 40
Figure Inquiry: How does a Burmese python generate heat while incubating eggs? 20 5 10 15 20 25 30 35
Contractions per minute

73. 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

74. 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

75. Thermostat in hypothalamus activates cooling mechanisms.
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.
Figure The thermostatic function of the hypothalamus in human thermoregulation
Response: Shivering
Response: Blood
vessels in skin
constrict.
Thermostat in
hypothalamus
activates warming
mechanisms.

76. Thermostat in Response: Blood hypothalamus vessels in skin dilate.
Figure 40.17a
Thermostat in
hypothalamus
activates cooling
mechanisms.
Response: Blood
vessels in skin dilate.
Response:
Sweat
Body temperature
increases.
Body temperature
decreases.
Figure 40.17a The thermostatic function of the hypothalamus in human thermoregulation (part 1: increase)
NORMAL BODY
TEMPERATURE
(approximately
36–38C)

77. NORMAL BODY TEMPERATURE (approximately 36–38C) Body temperature
Figure 40.17b
NORMAL BODY
TEMPERATURE
(approximately
36–38C)
Body temperature
decreases.
Body temperature
increases.
Response: Shivering
Response: Blood
vessels in skin
constrict.
Figure 40.17b The thermostatic function of the hypothalamus in human thermoregulation (part 2: decrease)
Thermostat in
hypothalamus
activates warming
mechanisms.

78. 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

79. 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

80. 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

81. Organic molecules in food External environment Animal body
Figure 40.18
Organic molecules
in food
External
environment
Animal
body
Digestion and
absorption
Heat
Energy lost
in feces
Nutrient molecules
in body cells
Energy lost in
nitrogenous
waste
Cellular
respiration
Carbon
skeletons
Heat
Figure Bioenergetics of an animal: an overview
ATP
Bio-
synthesis
Cellular
work
Heat
Heat

82. 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

83. Figure 40.19
Figure Measuring the rate of oxygen consumption by a swimming shark

84. 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

85. 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

86. 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

87. BMR (L O2/hr) (log scale) BMR (L O2/hr•kg)
Figure 40.20 10 3 8
Elephant
Shrew 7 10 2
Horse
Human 6
Sheep 10 5
BMR (L O2/hr) (log scale)
BMR (L O2/hr•kg)
Cat
Dog 4 1 3
Harvest mouse
Rat 2
Sheep −1
Mouse
Ground squirrel
Elephant 10
Shrew
Human
Mouse
Rat 1
Ground
squirrel
Cat
Dog
Horse
Harvest mouse −2 10 −3 −2 −1 2 3 −3 −2 −1 2 3 10 10 10 1 10 10 10 10 10 10 1 10 10 10
Figure The relationship of metabolic rate to body size
Body mass (kg) (log scale)
Body mass (kg) (log scale)
(a)
Relationship of basal metabolic rate (BMR) to body
size for various mammals
(b)
Relationship of BMR per kilogram of body mass to
body size

88. BMR (L O2/hr) (log scale)
Figure 40.20a 3 10
Elephant 2 2
Horse 10
Human
Sheep 10
BMR (L O2/hr) (log scale)
Cat
Dog 1
Rat −1 10
Ground squirrel
Shrew
Figure 40.20a The relationship of metabolic rate to body size (part 1: BMR)
Mouse
Harvest mouse −2 10 −3 −2 −1 2 3 10 10 10 1 10 10 10
Body mass (kg) (log scale)
(a)
Relationship of basal metabolic rate (BMR) to body
size for various mammals

89. Shrew Harvest mouse Sheep Mouse Elephant Human Rat Cat Ground Dog
Figure 40.20b 8
Shrew 7 6 5
BMR (L O2/hr•kg) 4 3
Harvest mouse 2
Sheep
Mouse
Elephant
Rat
Human 1
Ground
squirrel
Cat
Figure 40.20b The relationship of metabolic rate to body size (part 2: BMR per kg body mass)
Dog
Horse −3 −2 −1 2 3 10 10 10 1 10 10 10
Body mass (kg) (log scale)
(b)
Relationship of BMR per kilogram of body mass to
body size

90. 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

91. For most terrestrial animals, the average daily rate of energy consumption is 2–4 times BMR (endotherms) or SMR (ectotherms)
The fraction of an animal’s energy budget devoted to activity depends on factors such as environment, behavior, size, and thermoregulation

92. 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

93. Results Day Night Per2 Bmal1 100 80 60 Relative RNA level (%) 40 20
Figure 40.21
Results
Day
Night
Per2
Bmal1
100 80 60
Relative RNA level (%) 40
Figure Inquiry: What happens to the circadian clock during hibernation? 20
Euthermia
Hibernation
Euthermia
Hibernation

94. 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

95. 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

96. MAKE CONNECTIONS: Life Challenges and Solutions in Plants and Animals
Figure 40.22a
MAKE CONNECTIONS: Life Challenges and Solutions in
Plants and Animals
Environmental Response
Nutritional Mode
Growth and Regulation
Figure 40.22a Make connections: life challenges and solutions in plants and animals (part 1)

97. Environmental Response
Figure 40.22aa
Environmental Response
Figure 40.22aa Make connections: life challenges and solutions in plants and animals (part 1a: environmental response)
The floral head of a sunflower (left) and an insect’s eyes
(right) both contain photoreceptors that detect light.

98. Environmental Response
Figure 40.22aaa
Environmental Response
Figure 40.22aaa Make connections: life challenges and solutions in plants and animals (part 1aa: environmental response, sunflower head)
The floral head of a sunflower contains
photoreceptors that detect light.

99. Environmental Response
Figure 40.22aab
Environmental Response
Figure 40.22aab Make connections: life challenges and solutions in plants and animals (part 1ab: environmental response, insect eyes )
An insect’s eyes contain
photoreceptors that detect
light.

100. The broad surface of many leaves (left) enhances light capture for
Figure 40.22ab
Nutritional Mode
Figure 40.22ab Make connections: life challenges and solutions in plants and animals (part 1b: nutritional mode)
The broad surface of many leaves (left) enhances light capture for
photosynthesis. When hunting, a bobcat relies on stealth, speed, and sharp
claws (right).

101. The broad surface of many leaves
Figure 40.22aba
Nutritional Mode
Figure 40.22aba Make connections: life challenges and solutions in plants and animals (part 1ba: nutritional mode, autotroph)
The broad surface of many leaves
enhances light capture for photosynthesis.

102. When hunting, a bobcat relies on stealth, speed, and sharp claws.
Figure 40.22abb
Nutritional Mode
Figure 40.22abb Make connections: life challenges and solutions in plants and animals (part 1bb: nutritional mode, heterotroph)
When hunting, a bobcat relies on stealth, speed, and
sharp claws.

103. Figure 40.22ac
Growth and Regulation
Figure 40.22ac Make connections: life challenges and solutions in plants and animals (part 1c: growth and regulation)
In plants, hormones control growth patterns, flowering, fruit development,
and more (left). In animals, hormones control developmental events such
as molting (right).

104. Figure 40.22aca
Growth and Regulation
Figure 40.22aca Make connections: life challenges and solutions in plants and animals (part 1ca: growth and regulation, plant hormones)
In plants, hormones control growth patterns, flowering, fruit development,
and more.

105. In animals, hormones control developmental events such as molting.
Figure 40.22acb
Growth and Regulation
Figure 40.22acb Make connections: life challenges and solutions in plants and animals (part 1cb: growth and regulation, molting)
In animals, hormones control developmental events such as molting.

106. MAKE CONNECTIONS: Life Challenges and Solutions in Plants and Animals
Figure 40.22b
MAKE CONNECTIONS: Life Challenges and Solutions in
Plants and Animals
Transport
Reproduction
Gas Exchange
Absorption
Figure 40.22b Make connections: life challenges and solutions in plants and animals (part 2)

107. Plants harness solar energy to transport water,
Figure 40.22ba
Transport
Figure 40.22ba Make connections: life challenges and solutions in plants and animals (part 2a: transport)
Plants harness solar energy to transport water,
minerals, and sugars through specialized tubes (left).
in animals, a pump (heart) moves circulatory fluid
through vessels (right).

108. Plants harness solar energy to transport water, minerals,
Figure 40.22baa
Transport
Figure 40.22baa Make connections: life challenges and solutions in plants and animals (part 2aa: transport, plant circulation)
Plants harness solar energy
to transport water, minerals,
and sugars through
specialized tubes.

109. In animals, a pump (heart) moves circulatory fluid through vessels.
Figure 40.22bab
Transport
Figure 40.22bab Make connections: life challenges and solutions in plants and animals (part 2ab: transport, animal circulation)
In animals, a pump (heart)
moves circulatory fluid
through vessels.

110. Seeds (left) have stored food reserves that supply energy to the
Figure 40.22bb
Reproduction
Figure 40.22bb Make connections: life challenges and solutions in plants and animals (part 2b: reproduction)
Seeds (left) have stored food reserves that supply energy to the
young seedling, while milk provides sustenance for juvenile
mammals (right).

111. Seeds have stored food reserves that
Figure 40.22bba
Reproduction
Figure 40.22bba Make connections: life challenges and solutions in plants and animals (part 2ba: reproduction, seeds)
Seeds have stored food reserves that
supply energy to the young seedling.

112. Milk provides sustenance for juvenile mammals.
Figure 40.22bbb
Reproduction
Figure 40.22bbb Make connections: life challenges and solutions in plants and animals (part 2bb: reproduction, mammals)
Milk provides sustenance for
juvenile mammals.

113. The root hairs of plants (left) and the villi (projections)
Figure 40.22bc
Absorption
Figure 40.22bc Make connections: life challenges and solutions in plants and animals (part 2c: absorption)
The root hairs of plants (left) and the villi (projections)
that line the intestines of vertebrates (right) increase
the surface area available for absorption.

114. surface area available for absorption.
Figure 40.22bca
Absorption
Figure 40.22bca Make connections: life challenges and solutions in plants and animals (part 2ca: absorption, root hairs)
The root hairs of
plants increase the
surface area available
for absorption.

115. The villi (projections) that line the intestines of vertebrates
Figure 40.22bcb
Absorption
Figure 40.22bcb Make connections: life challenges and solutions in plants and animals (part 2cb: absorption, villi)
The villi (projections) that line
the intestines of vertebrates
increase the surface area
available for absorption.

116. In both plants and animals, highly convoluted surfaces have
Figure 40.22bd
Gas Exchange
Figure 40.22bd Make connections: life challenges and solutions in plants and animals (part 2d: gas exchange)
In both plants and animals, highly convoluted surfaces have
evolved, such as the spongy mesophyll of leaves (left) and
the alveoli of lungs (right).

117. In plants, highly convoluted surfaces have evolved, such as
Figure 40.22bda
Gas Exchange
Figure 40.22bda Make connections: life challenges and solutions in plants and animals (part 2da: gas exchange, mesophyll)
In plants, highly convoluted
surfaces have evolved, such as
the spongy mesophyll of leaves.

118. In animals, highly convoluted surfaces have evolved, such as
Figure 40.22bdb
Gas Exchange
Figure 40.22bdb Make connections: life challenges and solutions in plants and animals (part 2db: gas exchange, alveoli)
In animals, highly convoluted
surfaces have evolved, such as
the alveoli of lungs.

119. Basal (standard) metabolism Activity
Figure 40.UN01
Adélie penguin
4-kg male
340,000 kcal/yr
Deer mouse
0.025-kg female
4,000 kcal/yr
Ball python
4-kg female
8,000 kcal/yr
Figure 40.UN01 Skills exercise: interpreting pie charts
Key
Basal (standard) metabolism
Activity
Reproduction
Growth
Thermoregulation

120. (Muscardinus avellanarius)
Figure 40.UN02
Figure 40.UN02 In-text figure, hibernation, p. 887
Hibernating dormouse
(Muscardinus avellanarius)

121. NORMAL RANGE for internal variable Stimulus: change in Response
Figure 40.UN03
NORMAL RANGE
for internal variable
Response
Stimulus: change in
internal variable
Figure 40.UN03 Summary of key concepts: feedback control
Control center
Sensor

122. Figure 40.UN04
Figure 40.UN04 Test your understanding, question 13 (macaques)