Question

Enumerate the adaptations shown by animals to resist and survive in extreme colds.

Answer 1

Adaptations of animals to extreme cold

1. Cold hardening: Sessile animals (barnacles, molluscs) and insects resist cold spells.
2. Freeze-tolerant animals: Have ice-nucleating proteins that form ice in extracellular spaces, and cells stay supercooled to –40°C to –50°C.
3. Freeze-avoiding animals: Accumulate glycerol or antifreeze substances in blood to lower the freezing point of body fluids.
4. Conversion of glycogen to alcohols that protect cell membranes from freeze damage.
5. Hibernation in some animals, reducing metabolism and heart and breathing rates.
6. Thick fur, fat layers and reduced body surface in polar animals to minimise heat loss.