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Basic Principles of Animal Form and Function. Chapter 40 P. Biology Rick L. Knowles Liberty Senior High School. Figure 40.1. The comparative study of animals Reveals that form and function are closely correlated Natural selection can fit structure, anatomy, to function, physiology.

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basic principles of animal form and function

Basic Principles of Animal Form and Function

Chapter 40

P. Biology

Rick L. Knowles

Liberty Senior High School

slide2

Figure 40.1

  • The comparative study of animals
    • Reveals that form and function are closely correlated
    • Natural selection can fit structure, anatomy, to function, physiology
slide3
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?

slide4
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

exchange with the environment
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
slide6

Diffusion

(a) Single cell

  • A single-celled protist living in water
    • Has a sufficient surface area of plasma membrane to service its entire volume of cytoplasm

Figure 40.3a

slide7
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

(b) Two cell layers

Figure 40.3b

slide8

External environment

Food

CO2

O2

Mouth

Animal

body

Respiratory

system

Blood

50 µm

0.5 cm

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).

Cells

Heart

Nutrients

Circulatory

system

10 µm

Interstitial

fluid

Digestive

system

Excretory

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).

Inside a kidney is a mass of microscopic

tubules that exhange chemicals with

blood flowing through a web of tiny

vessels called capillaries (SEM).

Anus

Unabsorbed

matter (feces)

Metabolic waste

products (urine)

Figure 40.4

bioenergetics
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
energy sources and allocation
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
slide11
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

Cellular

respiration

Carbon

skeletons

Heat

ATP

Biosynthesis:

growth,

storage, and

reproduction

Cellular

work

Heat

Figure 40.7

Heat

quantifying energy use
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).
slide13

(a)

This photograph shows a ghost crab in arespirometer. Temperature is held constant in thechamber, with air of known O2 concentration flow-ing through. The crab’s metabolic rate is calculatedfrom the difference between the amount of O2entering and the amount of O2 leaving therespirometer. This crab is on a treadmill, runningat a constant speed as measurements are made.

(b) Similarly, the metabolic rate of a manfitted with a breathing apparatus isbeing monitored while he works outon a stationary bike.

Figure 40.8a, b

  • One way to measure metabolic rate
    • Is to determine the amount of oxygen consumed or carbon dioxide produced by an organism
bioenergetic strategies
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
endothermy
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
ectothermy
Ectothermy
  • Animal bodies gain body heat mostly from external sources.
  • Requires less energy.
  • Lower metabolic rates.
  • Ex. Most fish, amphibians, reptiles
ectotherm vs endotherm
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)
slide18

40

River otter (endotherm)

30

Body temperature (°C)

20

Largemouth bass (ectotherm)

10

0

10

20

30

40

Ambient (environmental) temperature (°C)

  • In general, ectotherms
    • Tolerate greater variation in internal temperature than endotherms

Figure 40.12

factors that affect metabolic rate
Factors that Affect Metabolic Rate
  • Ectothermic vs. Endothermic
  • Body Size
    • Metabolic rate is inversely related to mass. 1.0 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).
factors that affect metabolic rate1
Factors that Affect Metabolic Rate
  • Activity Level
    • Minimum metabolic rate required by a nongrowingendotherm 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, nonstressedectotherm at a given temp. – Standard Metabolic Rate (SMR).
  • Both endo- and ectotherms, max. metabolic rates (highest rated of ATP use) = peak activity.
activity and metabolic rate

500

A = 60-kg alligator

A

H

100

H

A

H = 60-kg human

50

H

Maximum metabolic rate

(kcal/min; log scale)

10

H

H

5

A

1

A

A

0.5

0.1

1

minute

1

second

1

hour

1

day

1

week

Time interval

Key

Existing intracellular ATP

ATP from glycolysis

ATP from aerobic respiration

Activity and Metabolic Rate

In general, an animal’s maximum possible metabolic rate is inversely related to the duration of the activity.

Endotherm Respiration Rate is 20 X an Ectotherm, causes less endurance

Figure 40.9

other factors affecting metabolic rate
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)
energy budgets
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.
slide24

Endotherms

Ectotherm

Reproduction

800,000

Temperature

regulation costs

Basal

metabolic

rate

Growth

340,000

Activity

costs

Annual energy expenditure (kcal/yr)

8,000

4,000

0.025-kg female deer mouse

from temperate

North America

4-kg male Adélie penguin

from Antarctica (brooding)

60-kg female human

from temperate climate

4-kg female python

from Australia

(a)

Total annual energy expenditures

438

Human

233

Energy expenditure per unit mass

(kcal/kg•day)

Python

Deer mouse

Adélie penguin

36.5

5.5

Energy expenditures per unit mass (kcal/kg•day)

(b)

advantages of endothermy
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.
modes of heat exchange

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.

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.

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.

Modes of Heat Exchange
  • Organisms exchange heat by four physical processes

Figure 40.13

balancing heat loss and gain
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:
1 insulation
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)
slide29
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

2 circulatory adaptations
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
slide32

Pacific

bottlenose

dolphin

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.

1

Canada

goose

Blood flow

1

Artery

Vein

Vein

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.

2

Artery

3

35°C

33°

3

30º

27º

20º

18º

2

10º

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.

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.

2

3

  • Many marine mammals and birds
    • Have arrangements of blood vessels called countercurrent heat exchangers that are important for reducing heat loss

3

1

Figure 40.15

slide33

21º

23º

25º

27º

29º

31º

Body cavity

Skin

Artery

Vein

Blood

vessels

in gills

Capillary

network within

muscle

Heart

Artery and

vein under

the skin

Dorsal aorta

  • Some specialized bony fishes and sharks
    • Also possess countercurrent heat exchangers

(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

slide35
Many endothermic insects
    • Have countercurrent heat exchangers that help maintain a high temperature in the thorax – where flight muscles are located.

Figure 40.17

3 cooling by evaporative heat loss
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 50 -100X more efficient at transferring heat than air.

Fig. 40.18

4 behavioral responses
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

5 adjusting metabolic heat production
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 – nonshiveringthermogenesis (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.
slide39

PREFLIGHT

WARMUP

PREFLIGHT

FLIGHT

40

Thorax

35

Temperature (°C)

30

Abdomen

25

0

2

4

Time from onset of warmup (min)

  • Many species of flying insects
    • Use shivering to warm up before taking flight

Figure 40.20

adjustment to temp changes at cellular level
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.
torpor and energy conservation
Torpor and Energy Conservation
  • Torpor:
    • 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.
slide43
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)

0

Arousals

35

Body

temperature

30

25

20

Temperature (°C)

15

10

5

0

Outside

temperature

Burrow

temperature

-5

-10

-15

June

August

October

December

February

April

slide44
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.