1. Basic Principles of Animal Form and Function
Chapter 40
P. Biology
Rick L. Knowles
Liberty Senior High School

2. The comparative study of animals
Reveals that form and function are closely correlated
Natural selection can fit structure, anatomy, to function, physiology
Figure 40.1

3. Physical laws and the need to exchange materials with the environment
Concept 40.1: Physical laws and the environment constrain animal size and shape
Physical laws and the need to exchange materials with the environment
Place certain limits on the range of animal forms
Could they ever exist?

4. Convergent Evolution
Reflects different species’ independent adaptation to a similar environmental challenge
(a) Tuna
(b) Shark
(c) Penguin
(d) Dolphin
Figure 40.2a–e
(e) Seal

5. Exchange with the Environment
An animal’s size and shape
Have a direct effect on how the animal exchanges energy and materials with its surroundings
Exchange with the environment occurs as substances dissolved in the aqueous medium
Diffuse and are transported across the cells’ plasma membranes

6. A single-celled protist living in water
Has a sufficient surface area of plasma membrane to service its entire volume of cytoplasm
Diffusion
(a) Single cell
Figure 40.3a

7. Multicellular organisms with a sac body plan
Have body walls that are only two cells thick, facilitating diffusion of materials
Mouth
Gastrovascular
cavity
Diffusion
Diffusion
Figure 40.3b
(b) Two cell layers

8. Figure 40.4 External environment Mouth Food CO2 O2 Animal body
Respiratory
system
Blood
50 µm
0.5 cm
Cells
A microscopic view of the lung reveals
that it is much more spongelike than
balloonlike. This construction provides
an expansive wet surface for gas
exchange with the environment (SEM).
Heart
Nutrients
Circulatory
system
10 µm
Interstitial
fluid
Digestive
system
The lining of the small intestine, a diges-
tive organ, is elaborated with fingerlike
projections that expand the surface area
for nutrient absorption (cross-section, SEM).
Excretory
system
Anus
Inside a kidney is a mass of microscopic
tubules that exhange chemicals with
blood flowing through a web of tiny
vessels called capillaries (SEM).
Unabsorbed
matter (feces)
Metabolic waste
products (urine)
Figure 40.4

9. Bioenergetics The flow of energy through an animal, its bioenergetics
Ultimately limits the animal’s behavior, growth, and reproduction
Determines how much food it needs
Studying an animal’s bioenergetics
Tells us a great deal about the animal’s adaptations

10. Energy Sources and Allocation
Animals harvest chemical energy
From the food they eat
Once food has been digested, the energy-containing molecules
Are usually used to make ATP, which powers cellular work

11. After the energetic needs of staying alive are met
Any remaining molecules from food can be used in biosynthesis
Organic molecules
in food
External
environment
Animal
body
Digestion and
absorption
Heat
Energy
lost in
feces
Nutrient molecules
in body cells
Energy
lost in
urine
Carbon
skeletons
Cellular
respiration
Heat
ATP
Biosynthesis:
growth,
storage, and
reproduction
Cellular
work
Heat
Figure 40.7
Heat

12. Quantifying Energy Use
An animal’s metabolic rate
Sum of all the energy-requiring biochemical reactions occurring over a given time.
Measured in calories (cal) or kilocalories (kcal).
1.0 kcal = 1, 000 cal.
1.0 Calorie (capital C) = 1 kcal = 1, 000 calories
Can be measured in a variety of ways:
Most energy from cell respiration becomes heat, can use a calorimeter to measure heat loss .
Measure the amount of oxygen consumed or carbon dioxide produced.
Rate of food consumption and energy content of food (4- 5 kcal/g of protein and carb and 9 kcal/g fat), but not all the energy in food is usable (feces and urine).

13. One way to measure metabolic rate
Is to determine the amount of oxygen consumed or carbon dioxide produced by an organism
Figure 40.8a, b
This photograph shows a ghost crab in a respirometer. Temperature is held constant in the chamber, with air of known O2 concentration flow- ing through. The crab’s metabolic rate is calculated from the difference between the amount of O2 entering and the amount of O2 leaving the respirometer. This crab is on a treadmill, running at a constant speed as measurements are made.
(a)
(b) Similarly, the metabolic rate of a man fitted with a breathing apparatus is being monitored while he works out on a stationary bike.

14. Bioenergetic Strategies
An animal’s metabolic rate is related to its bioenergetic strategy.
The type of strategy dictates rate of metabolism.
There are TWO basic types

15. Endothermy
Animal bodies are warmed mostly by heat generated from metabolism.
Maintain a narrow range of body temp.
High energy strategy for long-duration activity over a wide range of environmental temps.
Requires more daily calories.
Ex. Most birds and mammals

16. Ectothermy Animal bodies gain body heat mostly from external sources.
Requires less energy.
Lower metabolic rates.
Ex. Most fish, amphibians, reptiles

17. Ectotherm vs. Endotherm
Ectotherms regulate body temp. through behavior – basking or hiding in burrows – to regulate body temp.
Some ectotherms have a narrow range of body temps. – marine fish in waters that don’t vary much.
Some endotherms experience wide variation in body temps. – sloth has +/- 10 °C
Not mutually exclusive – endothermic birds may sun themselves to warm up or digest food.
Homeothermic (stable) vs. Poikilothermic (variable)

18. In general, ectotherms
Tolerate greater variation in internal temperature than endotherms
River otter (endotherm)
Largemouth bass (ectotherm)
Ambient (environmental) temperature (°C)
Body temperature (°C) 40 30 20 10
Figure 40.12

19. Factors that Affect Metabolic Rate
Ectothermic vs. Endothermic
Body Size
Metabolic rate is inversely related to mass g of mouse requires 20 X calories than 1.0 g of elephant.
Higher metabolic rate of smaller animals means higher 02 demand (cellular respiration rate), higher breathing rate, heart rate (pulse), and it must eat more food per unit body mass.
Why? Higher S. A to Vol. ratio; greater loss of heat in smaller animals (endothermic).

20. Factors that Affect Metabolic Rate
Activity Level
Minimum metabolic rate required by a nongrowing endotherm at rest , with an empty stomach to power cell maintenance, breathing, and heartbeat – Basal Metabolic Rate (BMR).
BMR for Human Males = 1, 800 kcal/day
BMR for Human Females = 1,500 kcal/day
In an ectotherm, body temp. changes with env. temp.; must determine metabolic rate of a resting, fasting, nonstressed ectotherm at a given temp. – Standard Metabolic Rate (SMR).
Both endo- and ectotherms, max. metabolic rates (highest rated of ATP use) = peak activity.

21. Activity and Metabolic Rate
In general, an animal’s maximum possible metabolic rate is inversely related to the duration of the activity.
Maximum metabolic rate
(kcal/min; log scale)
500
100 50 10 5 1
0.5
0.1 A H
A = 60-kg alligator
H = 60-kg human
second
minute
hour
Time interval
day
week
Key
Existing intracellular ATP
ATP from glycolysis
ATP from aerobic respiration
Endotherm Respiration Rate is 20 X an Ectotherm, causes less endurance
Figure 40.9

22. Other Factors Affecting Metabolic Rate
Age
Gender
Size
Body and Environmental Temps.
Quality/Quantity of Food
Activity Level
Oxygen Availability/Delivery Efficiency
Hormones
Time of Day (nocturnal vs. diurnal animals)

23. Energy Budgets
Different species use energy in food in different ways, depending on environment, size, behavior, and endo vs. ectothermy.
Some animals have determinant growth – maximum size and stop growing at maturity. Ex. most mammals and birds. Use less energy for growth as adults.
Other species have indeterminant growth – continue to grow throughout their life as long as nutrition and temp are appropriate. Ex. fish, reptiles. Use some energy for growth as adults.

24. Energy expenditures per unit mass (kcal/kg•day)
Endotherms
Ectotherm
Annual energy expenditure (kcal/yr)
800,000
Basal
metabolic
rate
Reproduction
Temperature
regulation costs
Growth
Activity
costs
60-kg female human
from temperate climate
Total annual energy expenditures
(a)
340,000
4-kg male Adélie penguin
from Antarctica (brooding)
4,000
0.025-kg female deer mouse
from temperate
North America
8,000
4-kg female python
from Australia
Energy expenditure per unit mass
(kcal/kg•day)
438
Deer mouse
233
Adélie penguin
36.5
Human
5.5
Python
Energy expenditures per unit mass (kcal/kg•day)
(b)

25. Advantages of Endothermy
Higher BMRs to generate heat require:
More efficient circulatory and respiratory systems  allows for endurance activities; higher levels of aerobic metabolism (few ectotherms migrate).
Wide range of habitats (arctic, etc.).
Have mechanisms of cooling (sweating, panting, etc.) that allow them to tolerate extremes in temps. better.
Disadvantages: Must consume more calories/day.

26. Organisms exchange heat by four physical processes
Modes of Heat Exchange
Organisms exchange heat by four physical processes
Radiation is the emission of electromagnetic
waves by all objects warmer than absolute
zero. Radiation can transfer heat between
objects that are not in direct contact, as when
a lizard absorbs heat radiating from the sun.
Evaporation is the removal of heat from the surface of a
liquid that is losing some of its molecules as gas.
Evaporation of water from a lizard’s moist surfaces that
are exposed to the environment has a strong cooling effect.
Convection is the transfer of heat by the
movement of air or liquid past a surface,
as when a breeze contributes to heat loss
from a lizard’s dry skin, or blood moves
heat from the body core to the extremities.
Conduction is the direct transfer of thermal motion (heat)
between molecules of objects in direct contact with each
other, as when a lizard sits on a hot rock.
Figure 40.13

27. Balancing Heat Loss and Gain
Thermoregulation – requires the management of the heat budget (heat loss = heat gain).
All endotherms and some ectotherms can thermoregulate.
Five Categories of Adaptation for this:

28. 1. Insulation
Insulation, which is a major thermoregulatory adaptation in mammals and birds
Reduces the flow of heat between an animal and its environment
May include feathers, fur, or blubber (extra adipose)

29. In mammals, the integumentary system
Acts as insulating material
Hair
Epidermis
Sweat
pore
Muscle
Dermis
Nerve
Sweat
gland
Hypodermis
Adipose tissue
Blood vessels
Oil gland
Figure 40.14
Hair follicle

30. 2. Circulatory Adaptations
Many endotherms and some ectotherms
Can alter the amount of blood flowing between the body core and the skin
In vasodilation:
Increase in diameter of superficial blood vessels, triggered by nerve impulses that relax the smooth muscles.
Blood flow in the skin increases, facilitating heat loss
In vasoconstriction:
Decrease in diameter of superficial blood vessels.
Blood flow in the skin decreases, lowering heat loss

32. Many marine mammals and birds
Have arrangements of blood vessels called countercurrent heat exchangers that are important for reducing heat loss
In the flippers of a dolphin, each artery is
surrounded by several veins in a
countercurrent arrangement, allowing
efficient heat exchange between arterial
and venous blood.
Canada
goose
Artery
Vein
35°C
Blood flow
30º
20º
10º
33°
27º
18º 9º
Pacific
bottlenose
dolphin 2 1 3
Arteries carrying warm blood down the
legs of a goose or the flippers of a dolphin
are in close contact with veins conveying
cool blood in the opposite direction, back
toward the trunk of the body. This
arrangement facilitates heat transfer
from arteries to veins (black
arrows) along the entire length
of the blood vessels.
Near the end of the leg or flipper, where
arterial blood has been cooled to far below
the animal’s core temperature, the artery
can still transfer heat to the even colder
blood of an adjacent vein. The venous blood
continues to absorb heat as it passes warmer
and warmer arterial blood traveling in the
opposite direction.
As the venous blood approaches the
center of the body, it is almost as warm
as the body core, minimizing the heat lost
as a result of supplying blood to body parts
immersed in cold water. 1 3
Figure 40.15

33. Some specialized bony fishes and sharks
Also possess countercurrent heat exchangers
21º
25º
23º
27º
29º
31º
Body cavity
Skin
Artery
Vein
Capillary
network within
muscle
Dorsal aorta
Artery and
vein under
the skin
Heart
Blood
vessels
in gills
(a) Bluefin tuna. Unlike most fishes, the bluefin tuna maintains
temperatures in its main swimming muscles that are much higher
than the surrounding water (colors indicate swimming muscles cut
in transverse section). These temperatures were recorded for a tuna
in 19°C water.
(b) Great white shark. Like the bluefin tuna, the great white shark
has a countercurrent heat exchanger in its swimming muscles that
reduces the loss of metabolic heat. All bony fishes and sharks lose
heat to the surrounding water when their blood passes through the
gills. However, endothermic sharks have a small dorsal aorta,
and as a result, relatively little cold blood from the gills goes directly
to the core of the body. Instead, most of the blood leaving the gills
is conveyed via large arteries just under the skin, keeping cool blood
away from the body core. As shown in the enlargement, small
arteries carrying cool blood inward from the large arteries under the
skin are paralleled by small veins carrying warm blood outward from
the inner body. This countercurrent flow retains heat in the muscles.
Figure 40.16a, b

34. Fig

35. Many endothermic insects
Have countercurrent heat exchangers that help maintain a high temperature in the thorax – where flight muscles are located.
Figure 40.17

36. 3. Cooling by Evaporative Heat Loss
Many types of mammals and birds:
Lose heat through the evaporation of water in sweat.
Use panting to cool their bodies (floor of the mouth of birds is rich in capillaries for heat loss when they pant).
Water is X more efficient at transferring heat than air.
Fig

37. 4. Behavioral Responses Both endotherms and ectotherms
Use a variety of behavioral responses to control body temperature (Ex. moving in and out of sun)
Some terrestrial invertebrates
Have certain postures that enable them to minimize or maximize their absorption of heat from the sun
Figure 40.19

38. 5. Adjusting Metabolic Heat Production
Since endotherms are often warmer than surroundings, must counteract heat loss.
May shiver (involuntary muscle contraction) to warm themselves.
Some mammals use hormones to cause mitochondria to increase activity and produce heat rather than ATP – nonshivering thermogenesis (NST).
Hibernating mammals and human babies have brown fat –used to rapidly produce heat. (brown due to rich blood supply).
Some reptiles – female pythons – coil around eggs and shiver to warm eggs.

39. Time from onset of warmup (min)
Many species of flying insects
Use shivering to warm up before taking flight
PREFLIGHT
WARMUP
FLIGHT
Thorax
Abdomen
Temperature (°C)
Time from onset of warmup (min) 40 35 30 25 2 4
Figure 40.20

40. Fig

41. Adjustment to Temp. Changes at Cellular Level
If mammals cells in vitro are grown at higher temperature, there is an increase in heat-shock proteins – stabilize proteins from being denatured.
Cells may produce enzymes with different optimum temp. functions.
Some arctic species of fish and amphibians produce cryoprotectants –prevent ice formation inside tissues and cells.

42. Torpor and Energy Conservation
Is an adaptation that enables animals to save energy while avoiding difficult and dangerous conditions.
Is a physiological state in which activity is low and metabolism decreases.

43. Hibernation is long-term torpor
That is an adaptation to winter cold and food scarcity during which the animal’s body temperature declines
Additional metabolism that would be
necessary to stay active in winter
200
Actual
metabolism
100
Figure 40.22
Metabolic rate
(kcal per day)
Arousals 35
Body
temperature 30 25 20
Temperature (°C) 15 10 5
Outside
temperature -5
Burrow
temperature
-10
-15
June
August
October
December
February
April

44. Estivation, or summer torpor:
Enables animals to survive long periods of high temperatures and scarce water supplies
Many reptiles estivate in the summer months.
Daily torpor:
Is exhibited by many small mammals and birds and seems to be adapted to their feeding patterns.
Many nocturnal animals (bats and shrews) feed at night and then go into torpor during daylight hours.