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3/16/2015
1
CAMPBELL
BIOLOGYReece • Urry • Cain • Wasserman • Minorsky • Jackson
© 2014 Pearson Education, Inc.
TENTH
EDITION
40
Lecture Presentation by
Nicole Tunbridge and
Kathleen Fitzpatrick
Basic Principles
of Animal Form
and Function
© 2014 Pearson Education, Inc.
1. Overview of Form & Function
© 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
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© 2014 Pearson Education, Inc.
Evolution of Animal Size and Shape
Physical laws govern strength,
diffusion, movement, and heat
exchange
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
Seal
Penguin
Tuna
© 2014 Pearson Education, Inc.
Exchange with the Environment
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
© 2014 Pearson Education, Inc.
Exchange
Mouth
Gastrovascular
cavity
Exchange
Exchange
A hydra, an animal with two
layers of cells
(b)(a) An amoeba, a single-celled
organism
0.1 mm 1 mm
A single-celled organism living in water has sufficient
surface area to carry out all necessary exchange
Multicellular organisms with a saclike body plan have
body walls that are only two cells thick, facilitating
diffusion of materials
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© 2014 Pearson Education, Inc.
In flat animals such as tapeworms, most cells are
in direct contact with its environment
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
© 2014 Pearson Education, Inc.
Figure 40.4
External environment
FoodMouth
Animal
body
O2
CO2
Respiratory
systemLung tissue (SEM)
Interstitial
fluid
Cells
Excretory
system
Blood vessels in
kidney (SEM)
50
µm
Heart
Circulatory
system
Nutrients
Digestivesystem
Anus
Metabolic wasteproducts (nitrogenous waste)
Unabsorbedmatter (feces)
25
0 µ
m
10
0 µ
m
Lining of small
intestine (SEM)
© 2014 Pearson Education, Inc.
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 living in a
variable environment to maintain a relatively stable
internal environment
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© 2014 Pearson Education, Inc.
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 40.1a
© 2014 Pearson Education, Inc.
Table 40.1b
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© 2014 Pearson Education, Inc.
2. Tissues
© 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.
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)
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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© 2014 Pearson Education, Inc.
Figure 40.5a
Epithelial Tissue
Stratifiedsquamousepithelium
Pseudostratifiedcolumnarepithelium
Simplesquamousepithelium
Simple columnarepithelium
Cuboidalepithelium
Apical
surface
Basal
surface
© 2014 Pearson Education, Inc.
Figure 40.5aa
Lumen Apical surface
Basal surface
10 µ
m
Polarity of epithelia
© 2014 Pearson Education, Inc.
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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© 2014 Pearson Education, Inc.
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
Connective tissue contains cells, including:
Fibroblasts that secrete the protein of extracellular fibers
Macrophages that are involved in the immune system
© 2014 Pearson Education, Inc.
In vertebrates, the fibers and foundation combine
to form six major types of connective tissue
1. Loose connective tissue binds epithelia to underlying
tissues and holds organs in place
2. Fibrous connective tissue is found in tendons, which
attach muscles to bones, and ligaments, which connect
bones at joints
3. Bone is mineralized and forms the skeleton
4. Adipose tissue stores fat for insulation and fuel
5. Blood is composed of blood cells and cell fragments in
blood plasma
6. Cartilage is a strong and flexible support material
© 2014 Pearson Education, Inc.
Figure 40.5b
Connective Tissue
Loose connective tissue Blood
Red blood cells
Chondrocytes
Chondroitin sulfate
Fat dropletsCentral
canal
Osteon
Nuclei
Elastic fiber
Collagenous fiberWhitebloodcells
Plasma
Cartilage
Adipose tissueBone
Fibrous connective tissue
12
0 µ
m3
0 µ
m
15
0 µ
m
10
0 µ
m
55
µm
70
0 µ
m
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© 2014 Pearson Education, Inc.
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
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
© 2014 Pearson Education, Inc.
Figure 40.5c
Muscle Tissue
Skeletal muscle
Smooth muscle Cardiac muscle
Nuclei
Sarcomere
Muscle
fiber
100 µm
Nucleus Musclefibers
25 µm 25 µmIntercalateddisk
Nucleus
© 2014 Pearson Education, Inc.
Nervous Tissue
Neurons
Neuron:
Dendrites
Cell body
Axon
(Fluorescent LM)(Confocal LM)
40
µm
Glia
Axons ofneurons
Bloodvessel
Glia15 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
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© 2014 Pearson Education, Inc.
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
Endocrinecell
Hormone
Signal travelseverywhere.
Bloodvessel
Nerveimpulse
Axons
Nerveimpulse
Signal travelsto a specificlocation.
Axon
Cell bodyof neuron
(b) Signaling by neurons
STIMULUS
ResponseResponse
© 2014 Pearson Education, Inc.
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
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© 2014 Pearson Education, Inc.
3. Regulation & Homeostasis
© 2014 Pearson Education, Inc.
Feedback control maintains the internal environment in many animals
Faced with environmental fluctuations, animals manage
their internal environment by either regulating or
conforming
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
© 2014 Pearson Education, Inc.
Figure 40.7
River otter (temperature regulator)
Largemouth bass(temperature conformer)
40
30
20
10
00 10 20 30 40
Ambient (environmental)
temperature (C)
Bo
dy t
em
pe
ratu
re (C
)
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© 2014 Pearson Education, Inc.
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
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
Room temperatureincreases.
Room temperaturedecreases.
Room temperaturedecreases.
Room temperatureincreases.
Thermostat turnsheater off.
Thermostat turns heater on.
ROOMTEMPERATURE
AT 20C (set point)
© 2014 Pearson Education, Inc.
Feedback Control in Homeostasis
Homeostasis in animals relies largely on negative
feedback, which helps return a variable to a normal
range
Positive feedback amplifies a stimulus and does not
usually contribute to homeostasis in animals
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
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© 2014 Pearson Education, Inc.
Figure 40.9Body
temperatureMelatonin
concentration
60
40
20
0
Mela
ton
in c
on
cen
trati
on
in b
loo
d (
pg
/mL
)
10AM
6AM
6PM
10PM
2AM
2PM
37.1
36.9
36.7
36.5
Co
re b
od
y t
em
pera
ture
(C
)
Time of day
Variation in core body temperature and melatoninconcentration in blood
(a)
Start ofmelatonin secretion
Midnight
6 PM
Greatest
muscle
strength
Lowestheart rate
Lowest body
temperature
Most rapidrise in blood
pressure
6 AM
Noon
Fastestreaction time
Highest risk
of cardiac arrest
(b) The human circadian clock
© 2014 Pearson Education, Inc.
Homeostasis can adjust to changes in external
environment, a process called acclimatization
© 2014 Pearson Education, Inc.
Homeostatic processes for thermoregulation involve form, function, and behavior
Thermoregulation is the process by which animals
maintain an internal temperature within a tolerable range
Endothermy and Ectothermy
Endothermic animals generate heat by metabolism;
birds and mammals are endotherms
Ectothermic animals gain heat from external sources;
ectotherms include most invertebrates, fishes,
amphibians, and nonavian reptiles
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© 2014 Pearson Education, Inc.
(a) A walrus, an endotherm
(b) A lizard, an ectotherm
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.
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)
© 2014 Pearson Education, Inc.
Figure 40.12
Radiation Evaporation
ConductionConvection
Balancing Heat Loss and Gain Organisms exchange heat by four physical processes:
radiation, evaporation, convection, and conduction
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© 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
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Circulatory Adaptations
Regulation of blood flow near the body surface
significantly affects thermoregulation
Many endotherms and some ectotherms can alter
the amount of blood flowing between the body
core and the skin
In vasodilation, blood flow in the skin increases,
facilitating heat loss
In vasoconstriction, blood flow in the skin
decreases, lowering heat loss
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© 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
Canadagoose
Bottlenosedolphin
VeinArtery
1
33
2
2
1 3VeinArtery
Key
Warm blood Blood flow
Cool blood Heat transfer
33
27
18
9
20
10
30
35C
© 2014 Pearson Education, Inc.
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
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© 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.
Figure 40.15
PREFLIGHT PREFLIGHTWARM-UP
FLIGHT
Thorax
Thorax
Abdomen
Abdomen
40
35
30
25
0 2
Time from onset of warm-up (min)
4
Te
mp
era
ture
(C
)
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© 2014 Pearson Education, Inc.
Figure 40.16
Results
120
100
80
60
40
20
00 5 10 15 20 25 30 35
Contractions per minute
O2
co
ns
um
pti
on
(m
L O
2/h
r•k
g)
© 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
© 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
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© 2014 Pearson Education, Inc.
Figure 40.17
Thermostat inhypothalamusactivates coolingmechanisms.
Response: Bloodvessels in skin dilate.
Body temperaturedecreases.
Body temperaturedecreases.
Body temperatureincreases.
Body temperatureincreases.
Response:Sweat
NORMAL BODYTEMPERATURE(approximately
36–38C)
Response: Shivering
Response: Bloodvessels in skinconstrict.
Thermostat inhypothalamusactivates warmingmechanisms.
© 2014 Pearson Education, Inc.
4. Bioenergetics
© 2014 Pearson Education, Inc.
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
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© 2014 Pearson Education, Inc.
Quantifying Energy Use
Metabolic rate is the amount of energy an animal
uses in a unit of time
Metabolic rate can be determined by measuring:
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
© 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
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© 2014 Pearson Education, Inc.
Figure 40.20a
Body mass (kg) (log scale)
Relationship of basal metabolic rate (BMR) to body
size for various mammals
Elephant
Horse
Human
Sheep
DogCat
Rat
ShrewGround squirrel
Mouse
Harvest mouse
103
BM
R (
L O
2/h
r) (
log
scale
)
210
10
2
1
10−1
10−3 10−2 10−1 1 10 102 10310−2
(a)
© 2014 Pearson Education, Inc.
Figure 40.20b
Elephant
Horse
Human
Sheep
DogCatRat
Shrew
Ground squirrel
Mouse
Harvest mouse
8
7
6
5
4
3
2
1
0
Body mass (kg) (log scale)
10 10 10 1 10 10 1032−1−2−3
Relationship of BMR per kilogram of body mass tobody size
BM
R (
L O
2/h
r•kg
)
(b)
© 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