Hello scientists

Why are mammals and birds warm-blooded? What is the reason behind this? How do we maintain this temperature, some sort of special organ?

Why are other animals not warm-blooded?

 

Thank you,

bonnie:confused:

How do we maintain this temperature, some sort of special organ?

 

nup, our internal workings do that for us, energy is produced through chemical reactions as the blood passes through the veins, and when we get to hot, the circulatory system brings plood to the surface to cool down.

thanks tash...but still left unanswered is WHY are mammals and birds warm-blooded? why aren't other animal endothermic?

Biologists aren't really great at answering why. The best answer we have now, is that warm-bloodedness must have been beneficial (or at least not harmful) in terms of the evolutionary process. There are advantages of warm blooded creatures over cold-blooded creatures.

There are advantages of warm blooded creatures over cold-blooded creatures.

 

What are the advantages of endothermic over ectothermic?

 

bonnie

First of all, it's not really a matter of simply "warm-blooded" and "cold-blooded." It's more of a continuous spectrum of species are more or less able to internally regulate their body temperatures. Birds and mammals are just a lot better at this than fish and reptiles, but all do it to some degree.

 

Different animals have various mechanisms for regulating temperature, but as for humans, we heat ourselves up by burning fat to produce heat, shivering muscles to increase respiration (a byproduct of which is heat), and constricting blood vessels near the skin so less of the core temperature is radiated outwards. We cool ourselves down by sweating (evaporation is endothermic), decreasing metabolism, and expanding surface blood vessels to radiate more.

 

The advantage of better temperature regulation is basically that we can be at "peak efficiency" regardless of environment. Our enzymes work best at body temperature, for example, and a stabile body temperature means we can be just as active in cold weather as hot. This naturally would have had evolutionary advantages, and so the mechanisms developed.

 

The reason not every animal is warm-blooded is because there are also advantages to the contrary. Less temperature regulation means less energy is used, and while a warm-blooded animal has to keep eating a lot in cold weather or else it will die, a cold-blooded animal can just slow down and barely need any food at all. So there are advantages to each.

In biology, things are faster when they're hot.

as an addition to what sisyphus said, fish are cold blooded because they would spend too much energy trying to keep themselves warm and not be able to cool themselves down. this is all because water is better at heat conduction than air. also phase change cooling isn't really possible.

...except if you're really big (like a whale) and have a very low surface/volume ratio.

well yeah, but there are only a few species of that size and shape. i was generalizing for simplicity.

by vasoconstriction and vasodilation we control our heat output, this allows us to travel at any tempretures, cold blooded creatures cannot.

 

 

its about adaption, a camel will try to trap in as much water as possible so it cant lose heat by evaporation, it must be able to handle huge temereture changes.

 

a polar bear is round to minimilize surface area, as it need to need warm. other animals do not need this as a priority.

 

being warm blooded has disadvantages, as you use more fuel, a snake can last on a meal for many months