Exotics thermoregulation SDL Flashcards
Define homeotherm
organism that maintains its body temp at a constant level by its metabolic activity
e.g., birds and mammals
Define poikilotherm
Organism that cannot regulate its body temp except by behavioural means
e.g., snakes, frogs
What are the advantages and disadvantages of homeotherms
Advantages:
- can regulate own body temp
- efficient body use
- more efficient enzyme activity as they function in specific temp range
Disadvantages:
- cannot survive in extreme temps
What are the pros and cons of poikilotherms
Pros:
- dont use energy to maintain temp
- dont need to feed each day as energy is not used in temp regulation
Cons:
- rely heavily on external temp to survive
What is normal bird temp?
39-43 degrees
Why is normal temp of birds and rabbits higher than others?
higher metabolic rate
more activity
What is metachromatism?
colour change of reptiles
How can metachromatism be used in thermoregulation?
by becoming a darker colour when cold => retain more heat
Becoming lighter => skin reflect light to prevent overheating
What cells in lizard skin enable them to use metachromatism in thermoregulation?
melanophores (contain melanin)
Describe the behavioural adaptations used by frogs to prevent freezing in cold weather
seek insulated hiding spots
may bury themselves in mud
Describe the physiological adaptations of frogs to prevent freezing in cold weather
Produce anti-freeze like compounds e.g., glucose, urea which lowers the freezing point of their bodily fluids preventing ice formation within their cells
What strategies do birds use to lose heat in hot weather?
Extending wings
elevate scapula feather to expose skin at back of neck
Shade seeking
Bathing
Why do birds have poor tolerance for high temps?
no sweat glands
Why do birds rely on behavioural adaptations to stay warm?
no brown adipose fat (used to burn calories to produce heat)
