Small organisms have a surface area that is large enough, compared with their volume. As a results they lose heat rapidly when the environmental temperature is lower than their body temperature. However when the animal gets bigger their volume increases at a larger rate than their surface area, so the surface to volume ratio decreases. Adaptations help organisms to survive in their habitats. Adaptations can be structural, behavioral and physiological. Cold resistant organisms evolved in various ways to cope with very low temperatures. Some animals hibernate, take shelter or migrate to warmer countries. Others, such as Antarctic seals have warm fur and a thick layer of fat for insulation. Antarctic seals are adapted to live in the sea and on the land. They’re big mammals which can survive in the cold and are adapted to not lose heat. For example in comparison to their bodies their heads are really small which decreases the heat loss. Also they have a large and thick layers of fats which insulated the animal on land and in water. Their fur is another characteristic that helps the seal to stay warm. The seal’s black skin reduces heat loss as it absorbs light from the sun and it does not reflect it.
Another example of Antarctic animals is a penguin. They have a compact shape, low surface area to volume ratio to reduce heat loss. They also have very thick specialized feathers and a layer of fat which is used for insulation.
An example of an animal which lives in hot environment is a desert tortoise. They can be active during the day or the mornings and evenings, it all depends on the temperature. They burrow under the sand to protect themselves from extreme hot temperatures. They can survive without water for nearly a year, they are able to obtain water from their diet as well. They can withdraw their head, legs, and tail into the shell providing themselves protection against...