Some Respiration Queries

[umer007]

How would the rate of respiration compare for a small reptile and small mammal of equal mass at 10 degrees celsius?

 

How would rate or respiration compare for small mammal at 10 degrees celsius and another small mammal at 20 degrees celsius?

 

How might rate of respiration compare for seeds that have been germinating for 0, 24, 48, 72 hours?

 

I am very confused at these, I think it may have something to do with the fact that mammals are warm blooded where reptiles are cold blooded but I dont know how to explain it. And the last question Im lost.

 

Plz help. Thx in advance

[rakuenso]

cellular respiration is probably directly related to the number of cells with a mitochondria, which in your case, is true for all examples.

 

 

just because they have equal mass doesn't mean they have equal number of cells, it also depends on if they are moving or not

 

in the second case i would say respiration is higher for the 10 degrees, because the body has to generate more heat to maintain its body temperature. If it's too hot, the body also needs to expel the excess heat in terms of sweat

 

seeds are bigger at 72 hours than at 0 hours, so my guess is that respiration is proportional to germination time

[Mokele]

The reptile would have about 10% to respiration of the mammal (possibly less), since mammals waste so much energy heating their bodies. Similarly, a mammal in the cold will have to spend more energy to keep warm. As for he plants, I don't really know, but rakuenso's answer seems plausible.

[umer007]

but wouldnt the 20 degrees mammal respire more since mammals prefer warmer temperatures?

 

And 20 is warmer than 10, cant most mammals withstand high temps? So why would they need to cool off ?

[Mokele]

The mammal itself isn't at 20 or 10, morely likely somewhere over 30. It needs to maintain that 30 or die. In colder environments, heat is lost more quickly, thus in order to keep their temperature constant, a mammal would need to burn more fuel.

 

Also, mammals can only tolerate a narrow range of internal temperatures, and all of their adaptations from everything from desert heat to polar winer hinge around retarding heat loss or enhancing heat loss to maintain themselves within that narrow internal range. Too cold and they have to burn extra energy to keep warm, too hot and they have to waste precious water cooling down.

 

Mokele

[umer007]

wt abt the mammal and reptile @ 10 degrees. DO they both respire the same? or do reptiles respire more @ 10 degrees to keep their temp more constant since they are at more unfavourable temp compared to mammal?

 

although in that case, wdnt the body temp of the reptile become warmer since respiration normally causes body temp to rise?

[rakuenso]

i think being cold blooded means that a reptile can function just as well at a lower temperature without respiring more to create heat. While a mammal cannot tolerate more than +-3 degrees from their normal body temperature (IIRC)

[Mokele]

Actually, think of it like this: you have an animal, which has a given surface area and thermal transfer properties governing how fast it loses heat. Without the production of internal heat, any animal will become room-temperature (like they do when dead). Now, this animal has two options:

1) It had respire very slowly, generating little heat, far less than needed to keep itself warm, and instead stay warm by using external energy sources such as the sun (this would be reptiles)

2) Respire a lot, burn a lot of food, and generate heat at the same rate it's lost in order to maintain a constant body temperature (this would be mammals).

 

Without an external heat source, a reptile will always cool down to room temperature. Because they don't generate any significant internal heat, they don't use as much food and don't respire as much, which is why they can do things like remain underwater for 6 hours at a time.

 

So in a 10 degree room, a reptile will just cool down (and probably go to sleep) without spending any more energy and thus without an increase in respiration. If you stick a thermometer up it's cloaca, you'll find the core body temperature to be 10 degrees, the same as the room. In contrast, a mammal *must* maintain it's high body temperature through burning fuel. The colder the environment is, the more rapidly an animal loses heat, so the mammal must generate more heat in cold environments to make up for the loss.

 

Mokele