This chapter discusses how physical laws and the environment constrain animal size and shape. It introduces key concepts around form and function relationships in animals. These include how different tissues (epithelial, connective, muscle, and nervous) relate to an animal's functions. The chapter also covers bioenergetics and how animals obtain and use energy. A major topic is homeostasis, how animals regulate internal conditions, comparing endothermic and ectothermic strategies. Thermoregulation mechanisms like insulation, circulation and behavior are examined.

1. Chapter 40

2. Problem Solving
 Animals must solve basic challenges of life:
 Obtain oxygen
 Nourish themselves
 Excrete waste products
 Move
 These questions will be addressed throughout
our next unit.
 Unifying themes that will be introduced here:
 Form & function are closely related

3. Vocabulary
 Anatomy – is the study of the structure of an
organism
 Physiology – is the study of the functions an
organism performs
 Bioenergetics – how organisms obtain,
process, and use their energy resources.
 Homeostasis – regulating internal
temperature

4. 40.1
 Physical laws and the
environment constrain
animal size and shape.
 An animal’s size and
shape (body plan or
design) affect the way
it interacts with its
environment.

5. Physical Laws
 Physical laws and the need to exchange
materials with the environment place certain
limits on the range of animals forms.
 Examples: Aquatic animals (sleek streamlined
body forms) and flying animals (bones that allow
for the organism to generate enough lift to
become air born)

6. Exchange with the
environment
 Living cells must be bathed in a aqueous
medium to keep the plasma membrane intact
 Single celled organisms – Surface-to-volume ratio
Fig. 40.3a

7. Multicellular organisms
 Composed of numerous
cells which also must be in
water
 Saclike body plan
 Hydra Fig. 40.3b
 Flat body plan –
tapeworm

9.  Both of these put a large surface area in
contact with the environment but do NOT
allow for complexity in internal organization
 Complex body forms allow for: outer
coverings to protect against predators, large
muscles for fast movement internal digestive
organs to break down food gradually,
maintaining relatively stable internal
environment, and for living on land.

10.  Animal form and function are correlated at all
levels of organization.
 Tissues are classified into 4 main categories –

11. Epithelial
 Sheets of tightly packed cells
 Where is it found? Epithelial tissue covers the
outside of the body and lines organs and
cavities within the body
 Form & function? Closely joined (tight
junctions between them) so epithelium
functions as a barrier against mechanical
injury, microbes, and fluid loss.

13.  Types?
 Stratified columnar
 Simple columnar
 Pseudostratified ciliated columnar
 Stratified squamous
 Simple squamous
 Cuboidal
 All have slightly different volumes of
cytoplasm which allow them to perform
different functions.

14. Connective Tissue
 Sparse population of cells scattered through
an extracellular matrix.
 Where is it found? Everywhere
 Form & function? Bind and support other
tissues

16.  Types?
 Loose connective tissue – holds organs in place
 Fibrous connective tissue – tendons & ligaments
 Cartilage
 Bone – mineralized connective tissue
 Blood
 Adipose tissue – stores fat

18. Muscles tissue
 Long cells called muscle fibers
 Where is it found? Everywhere!! Most
abundant tissue in most animals
 Form & function? Contraction brings about
movement

19.  Types?
 Skeletal – attaches to bones – voluntary movement
 Cardiac – striated – involuntary
 Smooth – lacks striations - involuntary

21. Nervous Tissue
 Nerve cells
 Organs & organ systems – see table 40.1 pg.
827

23.  Animals use the chemical energy in food to
sustain form and function
 Bioenergetics – limits the animal’s behavior,
growth, and reproduction and determines
how much food it needs.

24.  – After the energetic needs of staying alive
are met any remaining molecules from food
can be used in biosynthesis (body growth &
repair, storage material such as fat and
production of gametes)

26.  Metabolic rate – the sum of all the energy-
requiring biochemical reactions occurring
over a given time interval.
 Energy measured in Calories (cal) or kilocalories
(kcal)
 Unit Calorie with a capital C is actually a kilocalorie
 Energy appears as heat so metabolic rate can be
determined by measuring heat.

27. 2 Bioenergetic Strategies
 Endothermic – bodies are warmed mostly by
heat generated by matabolism and body
temperature is maintained within a relatively
narrow range.
 Ectothermic – meaning that they gain their
heat mostly from external sources

28. Endo or Ectothermic?

29. Endo or Ectothermic?

30. Endo or ectothermic?

31. Influences on metabolic
rate
 Size and metabolic rate: amount of energy it
takes to maintain each gram of body weight
is inversely related to body size. (Example –
each gram of a mouse requires about 20
times more calories than a gram of an
elephant)

33.  Activity and metabolic rate: every animal
experiences a range of metabolic rates. Basal
Metabolic rate (BMR) – metabolic rate of a
nongrowing endotherm that is at rest, has an
empty stomach, and is not experiencing
stress.
 1,600-1,800 kcal per day for adult male
 1,300-1,500 kcal per day for adult female

34.  Standard Metabolic rate (SMR) – metabolic rate of a
resting, fasting, nonstressed ectotherm at a
particular temperature.
 Maximum potential metabolic rates and ATP sources

35.  Energy budgets – pg. 831 Fig. 40.10

36. 40.4
 Many animals regulate their internal
environment within relatively narrow limits
 Interstitial fluid (Bernard more than a century
ago) – internal environment of vertebrates –
today homeostasis – steady state

37. Regulators vs. Conformers
 Regulators – animal is a regulator for a
particular environmental variable is it uses
internal control mechanisms to moderate
internal change in the face of external
fluctuation

38.  Conformer – an animal is said to be a
conformer for a particular environmental
variable if it allows its internal condition to
vary with certain external changes
 Regulators and conformers are extremes and
no animal is a perfect regulator or conformer
 Some animals may regulate some internal
conditions and conform to external
conditions for others.

39. Mechanisms of Homeostasis
 Negative feedback – thermostat in your
house pg. 832 Fig. 40.1
 Positive feedback – amplify rather than
reverse the change (child birth)

41.  Thermoregulation – process by which animals
maintain an internal temperature within a
tolerable range. Critical because most
biological processes work best at optimal
conditions (plasma membrane)

42. Ectotherms vs. Endotherms
 Ectotherms include invertebrates, fishes,
amphibians, lizards, snakes, and turtles
 The amount of heat they generate has little effect
on body temperature
 Bask in the sun to warm
 Seek shade to cool
 Can tolerate greater variation in internal
temperature than endotherms
 Not “cold-blooded”

43.  Endotherms include mammals, birds, some
fish, and numerous insect species
 Can use metabolic heat to regulate body
temperature
 Sweating to cool
 Not “warm-blooded”

44. Advantages & Disadvantages
 Advantages – able to generate a large amount of
heat metabolically – can perform vigorous activity
for much longer than is possible for most
ectotherms, can tolerate extreme temperatures
 Disadvantages – energetically expensive – requires
more food

45. Modes of heat exchange
 Conduction
 Convection
 Radiation
 Evaporation

47. Balancing heat loss & gain
 Insulation
 Circulatory adaptations
 Cooling by evaporative heat loss
 Behavioral responses
 Adjusting metabolic heat production

48. Insulation
 Skin, hair, nails, fur
 Skin houses nerves, sweat glands, blood
vessels, and hair follicles

49. Insulation

50. Circulatory adaptations
 Vasodilation (warms skin) – increases in
diameter of superficial blood vessels
 Vasoconstriction (cools skin) – reduces blood
flow and heat transfer by decreasing the
diameter of superficial blood vessels
 Countercurrent heat exchanger – important
for reducing heat loss in many endotherms

53. Cooling by evaporative heat
loss
 Water absorbs considerable heat when it
evaporates
 Panting
 Sweat glands
 Spreading saliva on body surface

54. Roxy panting!!

55. Behavioral responses
 Both ecto and endotherms
 Hibernation
 Migration
 Huddling in cold weather

58. Adjusting metabolic heat
production
 Endotherms must counteract constant heat
loss
 Heat production is increased by shivering
 NST – nonshivering thermogenesis (produce
heat instead of ATP)

59.  Feedback mechanisms
controlled by
hypothalamus in the
brain

60.  Acclimatization – both ectotherms and
endotherms can adjust to new range of
environmental temperatures.
 Shedding, growing a thicker coat
 Heat shock proteins – help maintain integrity of
cell’s proteins when exposed to extreme heat so
they don’t denature

62. Torpor & energy
conservation
 Torpor – a physiological state in which
activity is low and metabolism decreases
 Hibernation – long term torpor to winter cold and
food scarcity
 Estivation – summer torpor
 Daily torpor – adapted to feeding patterns