chapter 40 formn function
TRANSCRIPT
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Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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
Chapter 40Chapter 40
Basic Principles of Animal Form and Function
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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
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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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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
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Video: GalVideo: Galáápagos Sea Lionpagos Sea Lion
Video: Shark Eating SealVideo: Shark Eating Seal
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Fig. 40-2
(a) Tuna
(b) Penguin
(c) Seal
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Exchange with the Environment
• An animal’s size and shape directly affect how it exchanges energy and materials with its surroundings
• Exchange occurs as substances dissolved in the aqueous medium diffuse and are transported across the cells’ plasma membranes
• A single-celled protist living in water has a sufficient surface area of plasma membrane to service its entire volume of cytoplasm
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Video: Hydra Eating DaphniaVideo: Hydra Eating Daphnia
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Fig. 40-3
Exchange
0.15 mm
(a) Single cell
1.5 mm
(b) Two layers of cells
Exchange
Exchange
Mouth
Gastrovascularcavity
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• Multicellular organisms with a sac body plan have body walls that are only two cells thick, facilitating diffusion of materials
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• More complex organisms have highly folded internal surfaces for exchanging materials
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Fig. 40-4
0.5 cmNutrients
Digestivesystem
Lining of small intestine
MouthFood
External environment
Animalbody
CO2 O2
Circulatorysystem
Heart
Respiratorysystem
Cells
Interstitialfluid
Excretorysystem
Anus
Unabsorbedmatter (feces)
Metabolic waste products(nitrogenous waste)
Kidney tubules
10 µm
50 µ
m
Lung tissue
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Fig. 40-4a
Nutrients
Mouth
Digestivesystem
Anus
Unabsorbedmatter (feces)
Metabolic waste products(nitrogenous waste)
Excretorysystem
Circulatorysystem
Interstitialfluid
Cells
Respiratorysystem
Heart
Animalbody
CO2 O2Food
External environment
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Fig. 40-4b
Lining of small intestine
0.5 cm
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Fig. 40-4c
Lung tissue
50 µ
m
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Fig. 40-4d
Kidney tubules
10 µm
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• 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
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• Most animals are composed of specialized cells organized into tissues that have different functions
• Tissues make up organs, which together make up organ systems
Hierarchical Organization of Body Plans
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Table 40-1
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• Different tissues have different structures that are suited to their functions
• Tissues are classified into four main categories: epithelial, connective, muscle, and nervous
Tissue Structure and Function
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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
• The shape of epithelial cells may be cuboidal (like dice), columnar (like bricks on end), or squamous (like floor tiles)
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• 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)
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Fig. 40-5a
Epithelial Tissue
Cuboidalepithelium
Simplecolumnarepithelium
Pseudostratifiedciliatedcolumnarepithelium
Stratifiedsquamousepithelium
Simplesquamousepithelium
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Fig. 40-5b
Apical surface
Basal surfaceBasal lamina
40 µm
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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
– Elastic fibers stretch and snap back to their original length
– Reticular fibers join connective tissue to adjacent tissues
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• 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
– 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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– 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
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Fig. 40-5c
Connective Tissue
Collagenous fiber
Looseconnectivetissue
Elastic fiber12
0 µ
m
Cartilage
Chondrocytes
10
0 µ
m
Chondroitinsulfate
Adiposetissue
Fat droplets
15
0 µ
m
White blood cells
55
µm
Plasma Red bloodcells
Blood
Nuclei
Fibrousconnectivetissue
30
µm
Osteon
Bone
Central canal
70
0 µ
m
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Fig. 40-5d
Collagenous fiber
120
µm
Elastic fiber
Loose connective tissue
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Fig. 40-5e
Nuclei
Fibrous connective tissue
30 µ
m
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Fig. 40-5f
Osteon
Central canal
Bone
700
µm
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Fig. 40-5g
Chondrocytes
Chondroitinsulfate
Cartilage
100
µm
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Fig. 40-5h
Fat droplets
Adipose tissue
150
µm
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Fig. 40-5i
White blood cells
Plasma Red bloodcells
55 µ
m
Blood
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Muscle Tissue
• Muscle tissue consists of long cells called muscle fibers, which contract in response to nerve signals
• 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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Fig. 40-5j
Muscle Tissue
50 µmSkeletalmuscle
Multiplenuclei
Muscle fiber
Sarcomere
100 µm
Smoothmuscle
Cardiac muscle
Nucleus
Musclefibers
25 µm
Nucleus Intercalateddisk
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Fig. 40-5k
Skeletal muscle
Multiplenuclei
Muscle fiber
Sarcomere
100 µm
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Fig. 40-5l
Smooth muscle
Nucleus
Musclefibers
25 µm
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Fig. 40-5m
Nucleus Intercalateddisk
Cardiac muscle
50 µm
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Nervous Tissue
• Nervous tissue senses stimuli and transmits signals throughout the animal
• Nervous tissue contains:
– Neurons, or nerve cells, that transmit nerve impulses
– Glial cells, or glia, that help nourish, insulate, and replenish neurons
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Fig. 40-5n
Glial cells
Nervous Tissue
15 µm
Dendrites
Cell body
Axon
Neuron
Axons
Blood vessel
40 µm
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Fig. 40-5o
Dendrites
Cell body
Axon
40 µm
Neuron
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Fig. 40-5p
Glial cells
Axons
Blood vessel
Glial cells and axons15 µm
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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
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Fig. 40-6Stimulus
Hormone
Endocrinecell
Signal travelseverywherevia the bloodstream.
Bloodvessel
Response
(a) Signaling by hormones
Stimulus
Neuron
AxonSignal
Signal travelsalong axon toa specificlocation.
Signal
Axons
Response
(b) Signaling by neurons
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Fig. 40-6aStimulus
Endocrinecell
Hormone
Signal travelseverywherevia thebloodstream.
Bloodvessel
Response
(a) Signaling by hormones
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• 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
• Nerve impulses can be received by neurons, muscle cells, and endocrine cells
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Fig. 40-6bStimulus
Neuron
AxonSignal
Signal travelsalong axon toa specificlocation.
Signal
Axons
Response
(b) Signaling by neurons
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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
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• 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
Regulating and Conforming
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Fig. 40-7
River otter (temperature regulator)
Largemouth bass(temperature conformer)
Bo
dy
tem
per
atu
re (
°C)
0 10
10
20
20
30
30
40
40
Ambient (environmental) temperature (ºC)
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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
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• 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
Mechanisms of Homeostasis
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Animation: Positive FeedbackAnimation: Positive Feedback
Animation: Negative FeedbackAnimation: Negative Feedback
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Fig. 40-8Response:Heater turnedoff
Stimulus:Control center(thermostat)reads too hot
Roomtemperaturedecreases
Setpoint:20ºC
Roomtemperature
increases
Stimulus:Control center(thermostat)
reads too cold
Response:Heater turnedon
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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
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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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• 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
Endothermy and Ectothermy
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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
(a) A walrus, an endotherm
(b) A lizard, an ectotherm
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Variation in Body Temperature
• The body temperature of a poikilotherm varies with its environment, while that of a homeotherm is relatively constant
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Balancing Heat Loss and Gain
• Organisms exchange heat by four physical processes: conduction, convection, radiation, and evaporation
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Fig. 40-10Radiation Evaporation
Convection Conduction
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• Heat regulation in mammals often involves the integumentary system: skin, hair, and nails
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Fig. 40-11
Epidermis
Dermis
Hypodermis
Adipose tissue
Blood vessels
Hair
Sweatpore
Muscle
Nerve
Sweatgland
Oil glandHair follicle
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• Five general adaptations help animals thermoregulate:
– Insulation
– Circulatory adaptations
– Cooling by evaporative heat loss
– Behavioral responses
– Adjusting metabolic heat production
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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
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• 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
Circulatory Adaptations
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• 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
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Fig. 40-12
Canada goose Bottlenosedolphin
Artery
Artery
Vein Vein
Blood flow
33º35ºC
27º30º
18º20º
10º 9º
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• 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
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Cooling by Evaporative Heat Loss
• Many types of animals lose heat through evaporation of water in sweat
• 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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• Both endotherms and ectotherms use behavioral responses to control body temperature
• Some terrestrial invertebrates have postures that minimize or maximize absorption of solar heat
Behavioral Responses
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Fig. 40-13
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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
RESULTS
Contractions per minute
O2
con
sum
pti
on
(m
L O
2/h
r) p
er k
g
00
20
2015105 25 30 35
40
60
80
100
120
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Fig. 40-15
PREFLIGHT PREFLIGHTWARM-UP
FLIGHT
Thorax
Abdomen
Time from onset of warm-up (min)
Te
mp
era
ture
(ºC
)
0 2 4
25
30
35
40
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• 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
Acclimatization in Thermoregulation
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Physiological Thermostats and Fever
• Thermoregulation is controlled by a region of the brain called the hypothalamus
• The hypothalamus triggers heat loss or heat generating mechanisms
• Fever is the result of a change to the set point for a biological thermostat
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Fig. 40-16Sweat glands secrete sweat, which evaporates, cooling the body.
Thermostat in hypothalamus activates cooling mechanisms.
Blood vessels in skin dilate: capillaries fill; heat radiates from skin.
Increased body temperature
Decreased body temperature
Thermostat in hypothalamus activates warming mechanisms.
Blood vessels in skin constrict, reducing heat loss.
Skeletal muscles contract; shivering generates heat.
Body temperature increases; thermostat
shuts off warming mechanisms.
Homeostasis: Internal temperature
of 36–38°C
Body temperature decreases; thermostat
shuts off cooling mechanisms.
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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
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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
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Fig. 40-17Organic molecules
in foodExternalenvironment
Animalbody Digestion and
absorption
Nutrient moleculesin body cells
Carbonskeletons
Cellularrespiration
ATP
Heat
Energy lostin feces
Energy lost innitrogenouswaste
Heat
Biosynthesis
Heat
Heat
Cellularwork
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• 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
Quantifying Energy Use
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Fig. 40-18
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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
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• Metabolic rates are affected by many factors besides whether an animal is an endotherm or ectotherm
• Two of these factors are size and activity
Influences on Metabolic Rate
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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
• 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
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Fig. 40-19
Elephant
Horse
HumanSheep
DogCat
RatGround squirrel
MouseHarvest mouse
Shrew
Body mass (kg) (log scale)B
MR
(L
O2/
hr)
(Io
g s
cale
)
10–3 10–210–2
10–1
10–1
10
10
1
1 102
102
103
103
(a) Relationship of BMR to body size
Shrew
Mouse
Harvest mouse
Sheep
Rat CatDog
Human
Horse
Elephant
BM
R (
L O
2/h
r) (
per
kg
)
Ground squirrel
Body mass (kg) (log scale)10–3 10–2 10–1 1 10 102 103
0
1
2
3
4
5
6
8
7
(b) Relationship of BMR per kilogram of body mass to body size
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Fig. 40-19a
Shrew
Harvest mouseMouse
Ground squirrel
Rat
Cat Dog
Sheep
Human
Horse
Elephant
Body mass (kg) (log scale)
BM
R (
L O
2/h
r) (
log
sc
ale
)
(a) Relationship of BMR to body size
10–3 10–210–2
10–1
10–1
1
1
10 102 103
10
102
103
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Fig. 40-19b
10310210110–110–210–30
1
2
3
4
5
6
7
8
Body mass (kg) (log scale)
(b) Relationship of BMR per kilogram of body mass to body size
BM
R (
L O
2/h
r) (
per
kg
)Shrew
Harvest mouse
Mouse
Rat
Ground squirrel
Cat
Sheep
DogHuman
Horse
Elephant
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• 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
Activity and Metabolic Rate
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• Different species use energy and materials in food in different ways, depending on their environment
• Use of energy is partitioned to BMR (or SMR), activity, thermoregulation, growth, and reproduction
Energy Budgets
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Fig. 40-20
An
nu
al e
ner
gy
exp
end
itu
re (
kcal
/hr)
60-kg female humanfrom temperate climate
800,000Basal(standard)metabolism
ReproductionThermoregulation
Growth
Activity
340,000
4-kg male Adélie penguinfrom Antarctica (brooding)
4,000
0.025-kg female deer mousefrom temperateNorth America
8,000
4-kg female easternindigo snake
Endotherms Ectotherm
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Fig. 40-20a
An
nu
al e
ne
rgy
ex
pe
nd
itu
re (
kc
al/h
r)
60-kg female humanfrom temperate climate
800,000Basal(standard)metabolism
ReproductionThermoregulation
Growth
Activity
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Fig. 40-20b
Reproduction
Thermoregulation
Activity
Basal(standard)metabolism
4-kg male Adélie penguinfrom Antarctica (brooding)
An
nu
al e
ner
gy
exp
end
itu
re (
kcal
/yr)
340,000
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Fig. 40-20c
Reproduction
Thermoregulation
Basal(standard)metabolism
Activity
4,000
0.025-kg female deer mousefrom temperateNorth America
An
nu
al e
ner
gy
exp
end
itu
re (
kcal
/yr)
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Fig. 40-20d
Reproduction
Growth
Activity
Basal(standard)metabolism
4-kg female easternindigo snake
8,000
An
nu
al e
ner
gy
exp
end
itu
re (
kcal
/yr)
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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
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Fig. 40-21
Additional metabolism that would benecessary to stay active in winterActual
metabolism
Arousals
Bodytemperature
Outsidetemperature Burrow
temperature
Met
abo
lic
rate
(kca
l p
er d
ay)
Tem
per
atu
re (
°C)
June August October December February April–15
–10
–5
0
5
15
10
25
20
35
30
0
100
200
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• 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
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Fig. 40-UN1
Homeostasis
Stimulus:Perturbation/stress
Response/effector
Control center
Sensor/receptor
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Fig. 40-UN2
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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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