1. General Biology II Lecture 2-1
Chapter 40
Basic Principles of Animal Form and Function
林 翰 佳 老師

2. Before the class… What is an animal body made of (made from)?
How many kinds of tissue we have?
What is homeostasis?
What is energy budget?
What is the relationship between energy and animal size?

3. Overview Part 1: Animal form and function
Part 2: Feedback control and Homeostatic processes for thermoregulation
Part 3: Energy requirements of animals

4. Diverse Forms, Common Challenges
The comparative study of animals
Reveals that form and function are closely correlated
Natural selection can fit structure, anatomy, to function, physiology
By selecting, over many
generations, what works
best among the available
variations in a population

5. Concept 40.1
Physical laws constrain strength, diffusion, movement, and heat exchange
As animals increase in size, their skeletons must be proportionately
larger to support their
mass

6. Evolutionary convergence
Reflects different species’ independent adaptation to a similar environmental challenge
Osteichthye
Chondrichthye
(a) Tuna
All in Fusiform!
(b) Shark
Bird
Mammal
(c) Penguin
(d) Dolphin
Figure 40.2a–e
(e) Seal

7. 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

8. 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

9. Multicellular organisms with a sac (囊狀) body plan
Have body walls that are only two cells thick, facilitating diffusion of materials
Diffusion rate is related to surface
region size
With more cells, the surface…
Mouth
Gastrovascular
cavity
Diffusion
Saclike: hydra
Flat shape: Tapeworm
Diffusion
Figure 40.3b

10. Organisms with more complex body plans
Have highly folded internal surfaces specialized for exchanging materials
Digestive
system
Respiratory
Excretory
Circulatory
Extensively folded and branched internal!

11. Benefits for complex body form
Specialized outer covering provides extra protection.
Internal digestive organs improve energy absorption.
Internal body fluid provides relatively stable internal environment.
Complex body form is especially well suited for animals living on land.

12. Concept 40.1
Animal form and function are correlated at all levels of organization
Animals are composed of cells
Groups of cells with a common structure and function
Make up tissues
Different tissues make up organs
Which together make up organ systems

13. Tissue Structure and Function
Different types of tissues
Have different structures that are suited to their functions
Tissues are classified into four main categories
Epithelial, connective, muscle, and nervous

14. Epithelial Tissue Epithelial tissue
Covers the outside of the body and lines organs and cavities within the body
Contains cells that are closely joined
Function: a barrier against mechanical injury…
Types:
Simple epithelium, stratified, psudostratified..
Cuboidal, columnar, squamous…
Glandular epithelia, mucous membrane..

15. Types of epithelial tissue
Cuboidal
epithelium
Simple columnar
Simple squamous
Pseudostratified
columnar
Stratified squamous
Epithelial Tissue
Figure 40.5aa
Apical surface
Basal surface
Basal lamina
40 m
Polarity of epithelia

16. Connective Tissue Connective tissue
Functions mainly to bind and support other tissues
Contains sparsely packed cells scattered throughout an extracellular matrix (ECM)
6 types: loose connective tissue, adipose tissue, fibrous connective tissue, cartilage, bone and blood
ECM fibers: collagenous, elastic and reticular fiber

17. Types of connective tissue
Figure 40.5ba
Blood
Connective Tissue
Plasma
White
blood cells
55 m
Red blood cells
Cartilage
Chondrocytes
Chondroitin sulfate
100 m
Adipose tissue
Fat droplets
150 m
Bone
Central
canal
Osteon
700 m
Nuclei
Fibrous connective tissue
Elastic fiber
30 m
120 m
Collagenous fiber
Loose connective tissue

18. Muscle Tissue Muscle tissue
Is composed of long cells called muscle fibers capable of contracting in response to nerve signals
Contracting unit: myofibril: actin + myosin
Most abundant tissue in most animals
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

19. Types of muscle tissue

20. Nervous Tissue Nervous tissue
Neurons, or nerve cells, senses stimuli and transmits signals throughout the animal
Glial cells, or glia, that help nourish, insulate, and replenish neurons
Nervous Tissue
Neurons
Glia
Glia
15 m
Neuron:
Dendrites
Cell body
Axons of
neurons
Axon
Blood
vessel
40 m
(Fluorescent LM)
(Confocal LM)

21. Organs and Organ Systems
In all but the simplest animals
Different tissues are organized into organs
The tissues are
arranged in
layers
Lumen of
stomach
Mucosa. The mucosa is an
epithelial layer that lines
the lumen.
Submucosa. The submucosa is
a matrix of connective tissue
that contains blood vessels
and nerves.
Muscularis. The muscularis consists mainly of smooth muscle tissue.
0.2 mm
Serosa. External to the muscularis is the serosa, a thin layer of connective and epithelial tissue.
4 layers in stomach

22. Organ Systems Representing a level of organization higher than organs
Organ systems carry out the major body functions of most animals

23. 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

24. The effect of neurons
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, endocrine cells, and exocrine cells

25. Stimulation by hormones or neurons
Figure 40.6 Signaling in the endocrine and nervous systems 25

26. Responses of hormones or neurons
Figure 40.6 Signaling in the endocrine and nervous systems 26

27. End of Part 1 Ask your self…..
What laws constrain the size and shape of animals?
What are the four main categories of animal tissues? And what are the sub-categories?

28. Concept 40.2
Feedback control loops maintain the internal environment in many animals
The internal environment of vertebrates
is called the interstitial fluid (__________), and is very different from the external environment
Homeostasis is a balance between external changes
And the animal’s internal control mechanisms that oppose the changes

29. Regulating and Conforming
Are two extremes in how animals cope with environmental fluctuations
An animal is said to be a regulator
If it uses internal control mechanisms to moderate internal change in the face of external, environmental fluctuation
An animal is said to be a conformer
If it allows its internal condition to vary with certain external changes (spider crab)

30. Mechanisms of Homeostasis
Response
No heat
produced
Room
temperature
decreases
Heater
turned
off
Set point
Too
hot
Set
point
Control center:
thermostat
increases on
cold
Heat
Moderate changes in the internal environment
A homeostatic control system has three functional components
A receptor, a control center, and an effector

31. How a body controls homeostasis
Most homeostatic control systems function by negative feedback (負回饋)
Where buildup of the end product of the system shuts the system off
A second type of homeostatic control system is positive feedback (正回饋)
Which involves a change in some variable that triggers mechanisms that amplify the change
Ex. Childbirth

32. 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

33. Ectotherms and Endotherms
Include most invertebrates, fishes, amphibians, and non-bird reptiles
Endotherms (內溫動物)
Include birds and mammals
Animals are not classified as ectotherms or endotherms based on whether they have variable or constant body temperature.
Poikilotherm (變溫動物) and homeotherm (恆溫動物)
Cold-blooded and warm-blooded

34. 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 40.7

35. Endotherm Endothermy is more energetically expensive than ectothermy
But buffers animals’ internal temperatures against external fluctuations
And enables the animals to maintain a high level of aerobic metabolism
Advantages: perform vigorous activity for much longer and solves certain thermal problem of living on extreme environment!

36. 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)

37. Are we homeotherm?
Circadian clock 生理時鐘
Melatonin 褪黑激素

38. 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 40.10

39. Balancing Heat Loss and Gain
Thermoregulation involves physiological and behavioral adjustments that balance heat gain and loss.
General adaptations are:
Insulation
Circulatory adaptation
Cooling by evaporative heat loss
Behavioral responses
Adjusting metabolic heat production

40. #1 Insulation (隔熱)
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

41. The integumentary system (皮膚系統)
In mammals, the integumentary system acts as insulating material
How many kinds of tissue here?
Hair
Epidermis
Sweat
pore
Muscle
Dermis
Nerve
Sweat
gland
Hypodermis
Adipose tissue
Blood vessels
Oil gland
Figure 40.11
Hair follicle

42. #2 Circulatory Adaptations
Many endotherms and some ectotherms
Can alter the amount of blood flowing between the body core and the skin
In vasodilation (血管舒張)
Blood flow in the skin increases, facilitating heat loss
In vasoconstriction (血管收縮)
Blood flow in the skin decreases, lowering heat loss

43. Another circulatory adaptation
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 40.12

44. Specialized endothermic bony fishes
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.
(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.

45. Endothermic insects
Have countercurrent heat exchangers that help maintain a high temperature in the thorax
Q: How animals
produce heat?

46. #3 Cooling by Evaporative Heat Loss
Many types of animals
Lose heat through the evaporation of water in sweat
Use panting to cool their bodies
Bathing moistens the skin

47. #4 Behavioral Responses
Both endotherms and ectotherms
Use a variety of behavioral responses to control body temperature
Some terrestrial invertebrates have certain postures that enable them to minimize or maximize their absorption of heat from the sun
“Obelisk”

48. #5 Adjusting Metabolic Heat Production
Some animals can regulate body temperature
By adjusting their rate of metabolic heat production
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

49. Feedback Mechanisms in Thermoregulation
Thermostat in
hypothalamus
activates cooling
mechanisms.
Sweat glands secrete
sweat that evaporates,
cooling the body.
Blood vessels
in skin dilate:
capillaries fill
with warm blood;
heat radiates from
skin surface.
Body temperature
decreases;
thermostat
shuts off cooling
Increased body
temperature (such
as when exercising
or in hot
surroundings)
Homeostasis:
Internal body temperature
of approximately 36–38C
increases;
shuts off warming
Decreased body
temperature
(such as when
in cold
Blood vessels in skin
constrict, diverting blood
from skin to deeper tissues
and reducing heat loss
from skin surface.
Skeletal muscles rapidly
contract, causing shivering,
which generates heat.
activates
warming
Figure 40.16
Mammals regulate their body temperature
By a complex negative feedback system that involves several organ systems
In humans, a specific part of the brain, the hypothalamus
Contains a group of nerve cells that function as a thermostat

50. Adjustment to Changing Temperatures
In a process known as acclimatization
Many animals can adjust to a new range of environmental temperatures over a period of days or weeks
Acclimatization may involve cellular adjustments
Or in the case of birds and mammals, adjustments of insulation and metabolic heat production

51. End of Part 2 Ask yourself…
What is negative and positive feedback? Could you illustrate some examples?
How to categorize animals by their thermoregulation mechanism?
What are the general adaptations of animals’ thermoregulation?
What is countercurrent exchanger?

52. Concept 40.4
Energy requirements are related to animal size, activity, and environment
Animals use the chemical energy in food to sustain form and function
All organisms require chemical energy for
Growth, repair, physiological processes, regulation, and reproduction

53. 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

54. 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

55. Bioenergetic overview
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 40.17
Heat

56. Quantifying Energy Use
An animal’s metabolic rate
Is the amount of energy an animal uses in a unit of time
One way to measure metabolic rate
Is to determine the amount of oxygen consumed or carbon dioxide produced by an organism
This photograph shows a ghost crab in a respirometer.
(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.

57. Bioenergetic Strategies
An animal’s metabolic rate is closely related to its bioenergetic strategy
There are two basic strategies:
Ectothermic
Endothermic

58. Endothermic Birds and mammals are mainly endothermic, meaning that
Their bodies are warmed mostly by heat generated by metabolism
They typically have higher metabolic rates

59. Ectothermic
Amphibians and reptiles other than birds are ectothermic, meaning that
They gain their heat mostly from external sources
They have lower metabolic rates

60. Influences on Metabolic Rate
The metabolic rates of animals
Are affected by many factors
Size: Metabolic rate per gram is inversely related to body size among similar animals.
Activity
Energy budgets

61. Activity and Metabolic Rate
The basal metabolic rate (BMR)
Is the metabolic rate of an endotherm at rest
The standard metabolic rate (SMR)
Is the metabolic rate of an ectotherm at rest
For both endotherms and ectotherms
Activity has a large effect on metabolic rate

62. Maximum possible metabolic rate
Is inversely related to the duration of the activity
Endotherm is more capable of long-duration activities.
Average daily energy
consumption is 2~4
BMR or SMR
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
Figure 40.9

63. Size and metabolism Bigger animals  larger BMR
Smaller animals  larger BMR per body mass

64. Energy Budgets Different species of animals
Use the energy and materials in food in different ways, depending on their environment
For most animal: majority of food is devoted to ATP production (metabolism)

65. An animal’s use of energy
Is partitioned to BMR (or SMR), activity, homeostasis, growth, and reproduction
Keep warm
Cont. Growth
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)
Figure 40.20

66. 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

67. Hibernation (冬眠) 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 40.21
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

68. Estivation and Daily torpor
Estivation, or summer torpor (夏眠)
Enables animals to survive long periods of high temperatures and scarce water supplies
Daily torpor (日眠)
Is exhibited by many small mammals and birds and seems to be adapted to their feeding patterns

69. End of Part 3 Ask yourself… What is BMR and SMR?
Why bioenergentic strategy affects the maximum metabolic rate?
What is energy budgets? Why the energy budget is different in different animals?
What is torpor? How many kinds of torpor? Why some animals need torpor?

70. End of the class The key concepts which you have learned in Part 1