Temperature Regulation (Test Three) Flashcards
Explain the problems with maintaining biochemical stability at extreme cold and hot temperatures.
At extreme cold temps, metabolic reactions may be too slow to perform basic life functions
At extreme high temps, enzyme activity may be impaired or destroyed
Why are cold-blooded / warm-blooded not accurate terms?
Because some ectotherms that are currently in hot environments can be warmer than so called “warm-blooded” mammals
How do ectotherms keep a stable temperature?
Since the environment determines their temperature they behaviorally move to where there is more favorable temp
How do endotherms maintain a stable temperature?
They generate enough heat through their metabolism to elevate their own temp to a high and stable level
Explain the behavioral adaptations the desert lizard uses to maintain a stable temperature.
- In the early morning, they stick their head out to absorb heat in the cool morning
- When it gets a little warmer, they expose their bodies and flatten themselves
- During the hottest part of the day, they will find shade or completely burrow themselves
- Towards the end of the day, as the sun sets they come out again to bask and absorb heat
How do bees cool and warm themselves in ever changing environments?
To cool the hive, bees spread water over it or fan the outside.
To warm the hive they vibrate their wing muscles.
Why do small endotherms decrease metabolic activity?
Because they have a higher surface area to volume ratio than other animals that results in rapid heat loss.
Surface area - determines heat loss
Volume - determines heat generation
What is homeothermy?
Stable temperature
Does little, some, or most of a endotherm’s caloric intake go to generating heat?
Most of it
Explain how heat is lost in endotherms.
- Radiation - lost to space
- Conduction - when you lay on cold surfaces
- Convection - air movement
- Evaporation of water through evaporation
What are some adaptations that endotherms make for hot environments?
- Smaller animals burrow, which increases humidity, lowers temperatures, and reduces water loss
- Smaller animals also have morphological adaptations to facilitate rapid heat loss
- Larger animals have glossy light-colored fur that reflects sunlight, and have adapted to lose heat on the ventral side of the animal
- Larger animals also concentrate fat tissue in the back changes how heat is transferred
What are some adaptations of endotherms to cold environments?
- Generally speaking mammals and birds increase heat production while also insulating the heat that is being produced.
- Extremities in arctic birds and mammals are allowed to cool down to low temperatures near freezing to avoid heat loss
How does countercurrent heat exchange work?
The warm arterial blood in the extremities passes in close contact to the veins that have cold blood returning from the limbs, so that heat exchange across the vessels transfers nearly all the body heat to the returning vessel, which allows the body to stay warm and the limbs to function.
Why adaptive hypothermia needed for some birds and mammals?
Because endothermy is very energetically expensive and it can be difficult to support on cold nights.
What is daily torpor?
Daily torpor is adaptive hypothermia mechanism that drops the body’s temperature at night to prevent energy loss
