Body Temperature Regulation Flashcards
What happens if body temperature gets too low?
Slow metabolism
Inadequate oxygen supply
Freezing of cells
What happens if body temperature gets too high?
Proteins denature
Inadequate oxygen supply
Membrane structure alterations
What are the four heat exchange processes?
Radiation - 60% heat loss
Convection - 15% heat loss
Conduction - 3% heat loss
Evaporation - 22% heat loss
What are benefits of endotherms?
Can sustain high activity bursts
Can have nocturnal activity in all habitats
Can exploit colder environments
Can forage widely and migrate over long distances
What are the disadvantages of endotherms?
Require a larger body size with a lower SA:V
Metabolic rate is 5 times faster than ectotherms
More energy = more food = more water
Cannot devote large amounts of energy to reproduction
Poor colonisers of poor/arid environments
What are the benefits of ectotherms?
Metabolic rate is five times lower than endotherms
Less energy = less food = less water
Can devote large amount of energy budget to reproduction
Good colonies of poor/arid environments
What are the disadvantages of ectotherms?
No nocturnal niches (unless in tropics or summer temperate regions)
Cannot sustain high active bursts at risk of oxygen debt
Use anaerobic respiration for high energy activity
What are ectotherms?
Polkilotherms
Body temperature fluctuates with environment - rely on environment for body temperature
They are temperature conformers
Amphibians, reptiles, most invertebrates
What are endotherms?
Have a constant body temperature
Temperature regulators
Get heat from metabolism
What adaptations can organisms have for insulation?
Brown fat (adipose tissue)
Blubber
Fur/hair/feathers
What is a thermal neutral zone?
Range of temperatures in which animal does not expend energy to maintain body temperature
What sets the upper and lower critical limits for temperature?
The hypothalamus
How much does heat production increase by shivering?
500%
What does thyroxine do?
Increase basal metabolic rate
What heat exchange process does perspiration increase?
The convection rate
