12th Class Biology blank Thermoregulation

As far as temperature regulation is concerned, animals can be divided into two groups: poikilothermous and homeothermous.

Poikilothermic means 'having a variable temperature'. Poikilothermic animals are described as 'cold-blooded', their body temperature changing with fluctuation in the environmental temperature. Homeothermic means 'having the same temperature'. Homeothermic animals (mammals, birds and a few fishes like tuna fish and sword fish) are popularly described as 'warm-blooded'; their body temperature is independent of environmental temperature.

In cold conditions their blood is at a temperature higher than that of their surroundings. More useful terms are ectothermic and endothermic. Ectothermic animals, as the word implies, gain heat from the environment, i.e., from outside the body. Endothermic animals generate heat from within the body and keep it there.