The Habitat Directs Animal Adaptations

By Dave Hanks

How does a species survive when itís too hot, too cold, too wet or too dry? Over a period of years, the individuals that can stand the conditions better survive. Because itís difficult to reproduce when one is dead, those with the best survival traits do the reproducing. Gradually the resulting offspring become adapted to withstand the existing environmental conditions. Behavior is also an adaptation. (i.e. shade seeking to get out of the sun, seeking cover to get away from a cold wind, or trying to blend in with oneís surroundings, are some examples).

TOO HOT: Longer, slimmer appendages that allow the blood to be closer to the surface to expel heat, and fat deposits in one spot to avoid covering the body which prevents heat loss. Humps on camels and fat tails on desert sheep are prime examples.

TOO COLD: Just opposite of too hot. These animals have short limbs, thick bodies, with their fat distributed evenly over their bodies. They are usually bigger (i.e. Alaska Moose are larger than Idaho Moose) which lowers the percent of surface area in relation to size and preserves body warmth.

TOO DRY: These have a very interesting adaptation to satisfy their water needs Ė they make their own from the carbohydrates they eat. A carbohydrate molecule is simply 6 molecules of water with 6 carbon atoms attached. Kick the carbon atoms off the molecule and you have water. We humans do the same, but get rid of the water, which is necessary to get rid of other waste products and cleanse our systems. Hot climate animals have to have devised other means of cleansing their systems

TOO WET: These animals develop sleek, steam lined bodies, appendages for movement in water, and counter shading (Dark on dorsal surface and light underneath on their ventral areas Ė camouflage from both above and below).

The Greater Yellowlegs (Pictured) is a bird of THE WET. Notice its white belly and dark, mottled top. Itís well camouflaged.

(An example of counter shading)