Animals Form and Function

Question 1

What are some characteristics of an animal?

Answer 1

Heterotrophs, Multicellular, Eukaryotes that can move

Question 2

What is the needed relationship between surface area and volume in animals?

Answer 2

Larger in order to better exchange with the external environment
(Volume grows faster)

Question 3

What is Basic Metabolic Rate? What does it measure?

Answer 3

Metabolic rate at rest, empty stomach, normal temperature
Measure the amount of energy (ATP) used at rest

Question 4

Which has a higher metabolic rate, a rat or an elephant?

Answer 4

A rat would have a higher metabolic rate because it has a higher SA: V ratio

Larger animals have a lower SA: V ratio which means less gas exchange.

Question 5

List Three Ways animals have adapted to increase Surface Area. Give an example for each one.

Answer 5

1. Flattening: Gill Lamellae
2. Folding: Lumen and Villi in Intestine
3. Branching: Capillaries

Question 6

What is Homeostasis?

Answer 6

the maintenance of a stable internal environment in response to environmental changes.

Question 7

What factors are maintained Through Homeostasis?
Give some reason as to why?

Answer 7

1. Temperature (enzymes)
2. pH (proteins)
3. Water and Electrolyte Balance
4. Oxygen Levels
5. Nutrient absorption
6. Blood pressure

Question 8

What are the three steps involved in maintaining homeostasis? What takes place in each step?

Answer 8

1. Sensor: Detects stimuli from the internal or external environment
2. Integrator: Evaluates if an action is needed in response to the change. Instructs the Effector.
3. Effector: Mechanism that helps restore the desired condition back to normal.

Question 9

In general, what is the goal of the three steps involved in maintaining homeostasis?

Answer 9

To return to the Setpoint, which is the normal value

Question 10

What are the sensors and integrators when the body experiences a change in temperature?

Answer 10

Sensor: temperature receptors (skin, spinal cord, hypothalamus) record temperature

Integrator: Integrator: compares sensor input with a set point then instructs effectors (hypothalamus)

Question 11

What are some actions, the body takes when it gets too cold? (3)

Answer 11

1. Blood vessels near the surface constrict to lower blood flow and heat loss from the skin’s surface
2. The body shivers, which generates heat in the muscles
3. Chemical signals are sent to cells, which increase cellular respiration and heat production

Question 12

What are some actions, the body takes when it gets too hot? (3)

Answer 12

1. Blood vessels near the surface dilute to increase blood flow and allow more heat to escape through the skin’s surface
2. Sweat glands create water on the body’s surface which evaporates and causes heat loss
3. Respiratory centers stimulated to increase heat loss (panting)

Question 13

What are some ways animals conduct thermoregulation? (4)

Answer 13

1. Endotherms: Generate their own heat. Enough to warm tissues.
2. Exotherms: Absorb heat from the environment
3. Homeotherms: Maintain a constant body temperature
4. Poikilotherms: Change body temperature in response to the environment.

Question 14

What Strategies do Endotherms use?

Answer 14

Endotherms can warm themselves because their basal metabolic rates are extremely high

• Heat given off by a high rate of chemical reactions is enough to warm the body
• Mammals and birds retain this heat because they have elaborate insulating structures such as feathers or fur

Question 15

What strategies do Ectotherms use?

Answer 15

Ectotherms gain heat directly from the environment and only generate a small amount of heat as a by-product of metabolism

• Most heat gain is by radiation or conduction

Question 16

Compare Endotherms and Ectotherms.

Answer 16

• Endothermy and ectothermy are best understood as contrasting adaptive strategies
• Endotherms have higher metabolic rates and thus can be more active at all times
• But it costs a lot of energy to produce heat which is not available for other processes
• Ectotherms are able to thrive with much lower intakes of food and can use a greater proportion of their total energy intake to support reproduction

*But muscle activity and digestion slow when temperature drops, making them more vulnerable

Question 17

Why do animals hibernate?

Answer 17

• increase insulation
• stock up on food
• find protected den
• slow down metabolic rate * reduce body temperature
• “sleep”

Question 18

What are two types of Hibernators? Provide examples of each.

Answer 18

Facultative hibernators:
enter hibernation only when either cold-stressed, food-deprived, or both, (Ex. Bears)

Obligate hibernators:
animals that spontaneously, and annually, enter hibernation regardless of ambient temperature and access to food.
(Ex. bats, ground squirrels, and hedgehogs)

Question 19

How do animals survive freezing? Why?
List 2 strategies.

Answer 19

If the liquid in an animal freezes, ice crystals damage cells and tissues

1. Freeze avoidance: keep bodily fluids liquid below 0°C
2. Freeze tolerance: keep ice formation outside of cells

Question 20

How does Freeze avoidance work?

Answer 20

See Image

Question 21

How does Freeze tolerance work?

Answer 21

See Image

Question 22

How do Japanese bees combat agasinst wasps?

Answer 22

Hornets can tolerate no more than 44 °C but the bees survive at 46 °C.
So the Japanese bees crowd the hornet and vibrate vigorously to achieve a temp of 45°C.

Question 23

How does Heat exchange work?

Answer 23

Often through blood vessels

Concurrent:
Parallel flow
Large gradients -> disappear quickly
Less effective

Countercurrent -> (minimized heat loss)
Antiparallel flow
Small gradients -> maintained
More effective

Question 24

The camel is able to live in extremely hot environments. Identify anatomical and physiological adaptations of the camel to the extreme heat that help it control temperature homeostasis, as reviewed in class.

Answer 24

Camels have thick insulating layers of fur and fat, minimizing heat uptake by radiation or thermoconduction. To avoid overheating their blood and keeping especially the brain cool, the arteries leading to the brain are pre-cooled by a net of capillaries transporting cool blood in the opposite direction (countercurrent heat exchange). The blood flowing through the capillaries is cold because it has been cooled by passing the nasal cavity for a countercurrent heat exchange with the airways: dry, incoming air is moistened by the mucosa, and evaporation cools down the air and the tissues surrounding the airways. Upon exhaling, water is recaptured from the warm air, so that the water loss is minimized.

Question 25

A behavioural physiologist is studying the homeostatic control of blood pH. In a trial, a lizard runs on a treadmill for a set amount of time and the blood pH is measured. The blood pH drops as carbon dioxide is released into the bloodstream. Which component of the homeostatic feedback system is responsible for determining whether the blood pH is far enough from normal that a response is necessary?
Correct Answer

Answer 25

integrator

Question 26

An elephant and a mouse are both running in full sunlight, and both overheat by the same amount above their normal body temperatures. When they move into the shade and rest, which animal will cool down faster?

Answer 26

The mouse will because it has a higher surface area/volume ratio.

Question 27

What is an example of negative feedback?

Answer 27

When blood glucose concentration increases, the pancreas produces and releases the hormone insulin. Insulin acts to decrease blood glucose. As blood glucose decreases, the rate of production and release of insulin decreases.

Question 28

Countercurrent multiplier systems are common in animals. Which of the following schematics best represents a countercurrent exchanger?

Answer 28

Question 29

_________________ is an example of homeostasis integrating form (morphology), function(physiology) and behaviour

Answer 29

Thermoregulation

Question 30

Small organisms have a ____________ surface area to volume ratio and a ______ diffusion distance between the environment and cells.

Answer 30

Large

short

Question 31

Homeostasis depends on ___________ _____________ control which reduces or opposes the change or perturbation.

Answer 31

Negative Feedback

Question 32

Tempbody= ________ _______ - _______ ________

Answer 32

Heat Production - Heat Loss

Question 33

True or False
Homeostasis is not an absolutely fixed or static point.

Answer 33

True

more around a “set point” rather than at specific point

Question 34

True or False
Hibernation abandons maintenance of high body temperature and thus abandons homeostasis.

Answer 34

False

it does abandon high body temp maintenance but does not abandon homeostasis

Question 35

True or False
Ectotherms do not produce any heat

Answer 35

False

heat is a by-product of cellular respiration so it’s still produced by ectotherms but endotherms just produce much more heat per gram of tissue

Question 36

True or False
Body temperature in ectotherms depends on heat exchange with the environment

Answer 36

True

Question 37

As body size/mass increases what increases and what decreases?

Answer 37

Surface area to volume ratio decreases and distance between cells and environment increases

Question 38

Why is thermoregulation so important?

Answer 38

physiological and biochemical reaction rates are temperature sensitive, changing 2- 3 fold for every 10oC in body temp

Question 39

Name 4 mechanisms for regulation of heat loss or heat gain and give an example of each

Answer 39

1- insulation (hair, fur, feathers, goosebumps)

2- evaporative heat loss (sweating, licking, panting)

3- behavioural responses (basking, use of microhabitats)

4- circulatory adjustments- regulation of blood flow to minimize heat loss from the flow of warm blood to the body surface (countercurrent exchange)

Question 40

What is an example of positive feedback biology?

Answer 40

One example of biological positive feedback is at the onset of contractions in childbirth. When contraction occurs, oxytocin is released into the body stimulating more contractions. Thus, the result is an increased amplitude and frequency of contractions.