Temperature Regulation (Test Three)

Question 1

Explain the problems with maintaining biochemical stability at extreme cold and hot temperatures.

Answer 1

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

Question 2

Why are cold-blooded / warm-blooded not accurate terms?

Answer 2

Because some ectotherms that are currently in hot environments can be warmer than so called “warm-blooded” mammals

Question 3

How do ectotherms keep a stable temperature?

Answer 3

Since the environment determines their temperature they behaviorally move to where there is more favorable temp

Question 4

How do endotherms maintain a stable temperature?

Answer 4

They generate enough heat through their metabolism to elevate their own temp to a high and stable level

Question 5

Explain the behavioral adaptations the desert lizard uses to maintain a stable temperature.

Answer 5

1. In the early morning, they stick their head out to absorb heat in the cool morning
2. When it gets a little warmer, they expose their bodies and flatten themselves
3. During the hottest part of the day, they will find shade or completely burrow themselves
4. Towards the end of the day, as the sun sets they come out again to bask and absorb heat

Question 6

How do bees cool and warm themselves in ever changing environments?

Answer 6

To cool the hive, bees spread water over it or fan the outside.

To warm the hive they vibrate their wing muscles.

Question 7

Why do small endotherms decrease metabolic activity?

Answer 7

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

Question 8

What is homeothermy?

Answer 8

Stable temperature

Question 9

Does little, some, or most of a endotherm’s caloric intake go to generating heat?

Answer 9

Most of it

Question 10

Explain how heat is lost in endotherms.

Answer 10

1. Radiation - lost to space
2. Conduction - when you lay on cold surfaces
3. Convection - air movement
4. Evaporation of water through evaporation

Question 11

What are some adaptations that endotherms make for hot environments?

Answer 11

1. Smaller animals burrow, which increases humidity, lowers temperatures, and reduces water loss
2. Smaller animals also have morphological adaptations to facilitate rapid heat loss
3. Larger animals have glossy light-colored fur that reflects sunlight, and have adapted to lose heat on the ventral side of the animal
4. Larger animals also concentrate fat tissue in the back changes how heat is transferred

Question 12

What are some adaptations of endotherms to cold environments?

Answer 12

1. Generally speaking mammals and birds increase heat production while also insulating the heat that is being produced.
2. Extremities in arctic birds and mammals are allowed to cool down to low temperatures near freezing to avoid heat loss

Question 13

How does countercurrent heat exchange work?

Answer 13

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.

Question 14

Why adaptive hypothermia needed for some birds and mammals?

Answer 14

Because endothermy is very energetically expensive and it can be difficult to support on cold nights.

Question 15

What is daily torpor?

Answer 15

Daily torpor is adaptive hypothermia mechanism that drops the body’s temperature at night to prevent energy loss

Question 16

How is hibernation different from daily torpor?

Answer 16

Animals prepare for large amounts of time by storing body fat, and begin to gradually undergo small “test drops” in temperature, and eventually temp drops and metabolism decreases, and respiration and heart rate also drop.

Examples include ground squirrels, jumping mice, and woodchucks

Question 17

Explain what prolonged sleep or “summer sleep” is.

Answer 17

When animals enter a prolonged sleep with no decrease in body temperature, so this is not true hibernation.

Heart rate drops

Question 18

What is likely happening in a prolonged sleep if the breathing rates and metabolism decreases?

Answer 18

1. The animal is dehydrated
2. The temperature is high