Adaptions in Ectothermic and Endothermic Animals to Extreme Climates

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Adaptions in Ectothermic and Endothermic Animals to Extreme Climates

First of all we need to understand what ectothermic and endothermic animals are.

Animals differ in their abilities to regulate body temperature (thermoregulation). We sometimes use the terms "cold-blooded" or "warm-blooded." Most reptiles feel cold to the touch, while mammals and birds often feel warm.

Somewhat more precise descriptions can be made by using the terms poikilothermic and homoiothermic. The body temperature of poikllotherms is relatively variable, while that of homeotherms is relatively constant.

Even more useful terms are Ectothermic or Endothermic, which suggest two different mechanisms of thermoregulation. Ectotherms generally obtain heat from their external surroundings. Their body temperature varies, corresponding at any time with the temperature of their external environment.

Endothermic animals, on the other hand, have relatively constant body temperatures. Their body temperature is independent of that of their external environment. Monkeys and walruses, for example, both have body temperatures of about 38„aC, despite living in very different habitats.

However if body temperature rises above its optimum level (usually around 40„aC in mammals) then the enzyme rate inside the body will go into sharp decline. This is because enzymes are proteins, and become denatured. One of the first organs to be affected is the brain. Since the brain controls breathing and the circulation, the rise in body temperature disrupts the normal functioning of these important systems.

If the body temperature decreases dramatically (hypothermia) then this will slow metabolic activity and impairs brain function.

Here is a graph to show the relationsh...

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...ightly to allow some air to pass underneath it. Snakes can regulate their temperature by placing different proportions of their bodies in sun or in shade. The variations are numerous, but the end result is the same ¡V some degree of temperature regulation in reptiles.

In conclusion the animals which exist in the extreme climates of the world have adapted to be able to live well in these habitats and will probably stay living in these habitats for a long time to come.

Bibliography:

Bibliography

Books: Biology, Principles and processes

By Michael Roberts, Michael Reiss, Grace Monger

Life on earth and Life in the freezer

By David Attenborough

Hutchinsons Encyclopedia

Video: BBC Biological science-Endotherms and Ectotherms

Multimedia: Encarta 97 Encyclopedia

Internet: WWW.educationalimages.com

WWW.wildlifeonone.com

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