Question

Explain the following terms and give one or more synonymous terms for each:
(i) Poikilotherms ............................................................................................
(ii) Homoiotherms...........................................................................................

Answer 1

Poikilotherms ............................................................................................

» Cold blooded

Homoiotherms...........................................................................................

» Warm blooded

Answer 2

Answer:

Poikilotherms are the animals whose body temperature changes with the temperature of their surrounding environment. The synonym for poikilotherms is Cold-blooded animals.

Homeotherms are the animals whose internal body temperature remains constant irrespective of the temperature of the surrounding. These animals are also known as Warm-blooded animals.

Explanation:

Among the vertebrates, usually the primitive ones are Poikilothermic, that is, they cannot control the internal body temperature, it depends on the ambiance they are in. Whereas, in higher vertebrates,which are known as Homeotherms, the internal body temperature is maintained at a more or less fixed temperature, and is not affected by the surroundings they are in. This is called homeostasis.

The part of the brain responsible for maintaining a constant temperature is called thermostat which is situated in the hypothalamus. Among lower vertebrates like fish, amphibians, and reptiles, the brain lacks the hypothalamus. Hence, the inability to maintain body temperature. In the case of higher Vertebrates like mammals, the hypothalamus is developed along with the thermostat which is why these animals can control the body temperature. Nerves in the skin of these animals detect the change in external temperature and send the message to the hypothalamus to make the necessary change in the internal temperature to come to a constant.