Thermoregulation

Question 1

Homeothermy

Answer 1

Maintenance of a constant body temperature typically Warner than the environment

Question 2

Endothermy

Answer 2

Elevated metabolism (internally generated heat) in response to changes in ambient temperature

Question 3

Ectothermy

Answer 3

Use of external heat source (solar radiation) to maintain an elevated body temperature

Question 4

Poikilothermy

Answer 4

Conformance to ambient temperature

Question 5

What are some difficulties that marine animals encounter when thermoregulating in water?

Answer 5

• Water has a high specific heat capacity
• You loose heat more easily in water than in air

Question 6

How do seabirds thermoregulate?

Answer 6

Endothermy

Question 7

What is the thermoneutral zone?

Answer 7

The optimal temperature where an organism can thermoregulate without fluctuations in metabolic rate (requires less energy)

Question 8

Do bigger objects have a lower or higher surface area to volume ratio?

Answer 8

Lower

Question 9

How does the Surface area to volume ratio affect an organisms ability to retain heat?

Answer 9

• Organisms with a higher surface area to volume ratio loose less heat than organisms with smaller surface are to volume ratios
• Smaller organisms have a higher surface area to loose heat

Question 10

How do feathers help seabirds thermoregulate?

Answer 10

Semiplume and down feathers add insulation

Question 11

Describe the function of preen glands

Answer 11

Secrete wax that waterproof feathers

Question 12

Describe the function of brood patches

Answer 12

• Patch of heavily vascularized skin that lacks feathers in order to facilitate heat transfer to egg or chicks
• Present in breeding birds

Question 13

How do penguins maintain their thermoneutral zone?

Answer 13

Insulation (feather and fat)

Question 14

What is a more effective insulator fat or feathers?

Answer 14

• Feathers
• Fat is heavier than feathers and more energetically costly

Question 15

Describe the structure of penguin feathers

Answer 15

• Down is located near the bottom of the shaft
• When immersed in water feathers flattened
• On land down feathers become erect and trap air (adds insulation)
• Feather overlap makes them impenetrable to wind and water

Question 16

What affect do oil spills have on seabirds?

Answer 16

• Interferes with their ability to thermoregulate
• Oil disrupts water-repellent properties of plumage
• Water penetrates feathers and removes layer of trapped air
• More susceptible to hypothermia in cold waters

Question 17

Why is preening important in penguins?

Answer 17

It allows them to rearrange their feathers adding insulation by changing the angle of the feather shaft

Question 18

Regional heterothermy

Answer 18

Different regions of the body are maintained at different body temperatures

Question 19

How do seabirds conserve heat through regional heterothermy

Answer 19

• Conservation of core temperature
• Peripheral vasoconstriction
• Counter-current exchange

Question 20

Describe counter-current exchange

Answer 20

Close proximity of arteries and veins allows heat from warm arterial blood (coming from the body core) to warm colder venous blood (coming from extremities). Heat is conserved by recirculating blood to the warmer body core.

Question 21

How can penguins use their nasal passage to recapture heat lost through exhalation?

Answer 21

• During inhalation walls of nasal passage cool
• During exhalation, moist air from lungs cools and condenses in the surface of nasal walls
• Nasal passage becomes narrow
• Water loss and energy expenditure are limited

Question 22

How do seabirds behaviorally thermoregulate?

Answer 22

• Basking
• Tipping up feet to reduce contact to ice
• Huddling
• Seeking shade
• Burrowing
• Nocturnal behavior
• Constant movement (shivering, walking, swimming)

Question 23

What are some advantages of homeothermy?

Answer 23

• Organisms can live in a wide range of ambient temperatures
• Faster growth rate
• High activity rates
• Faster digestion
• Faster healing from injury

Question 24

What are some disadvantages of homeothermy/

Answer 24

• Larger food requirements
• 75% of all energy gained from food is used to thermoregulate
• less energy for growth and reproduction