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An adaption is a characteristic that increases the survival and reproductive chances of an organism in its environment. It is not a change that the organism makes in response to changes in its environment. There are 3 main types of adaptations; behavioural, structural and physiological.

Behavioural adaptations

These are seen in both ectotherms and endotherms. The main types of behavioural adaptations seen in animals are altering the position of their body and increasing or decreasing the amount of body surface exposed to sunlight. Many animals seek shade and shelter during the hottest parts of the day (red kangaroo). Nocturnal activity is another common behavioural adaptation, in which animals are relatively inactive during the day and become more active during the night, when it is much cooler (bilby). Migration is another behavioural adaptation which assists in the regulation of body temperature, these animals physically move to another habitat which is within their tolerance range (the grey plover).

Structural adaptations

One such adaptation is insulation with feathers, fur, scales and coats – these all enable a layer of air to be trapped close to the skin, which reduces heat loss. (emu) Blubber is another source of insulation. The surface area to volume is another structural component of temperature regulation, larger animals have a smaller surface area to volume ratio and hence lose less heat. Larger animals such as the wombat have small compact bodies, so to reduce their surface area and hence regulate their temperature more efficiently.

Physiological adaptations

These focus on the inner body functions. By altering its metabolic activity an organism is better able to survive in conditions above or below its tolerance range. Hibernation and torpor are examples of in which an organism lowers its metabolic rate to conserve energy and as a result, reduce the amount of metabolic heat energy. Hibernation is an extended period of inactivity in response to cold, where the body temperature does not drop below 30 degrees, but the heart rate and oxygen consumption drop considerably. Torpor is a state of short-term hibernation in which the body temperature drops below 30 degrees. The wombat slows down its metabolic rate to a third of its normal rate on hot days. Organisms can also regulate the blood flow in order to increase or decrease the amount of heat lost to the surroundings – through the process of vasodilation. A process known as countercurrent exchange allows the warm blood to hear the cooler blood, before it is returned to the heart – this occurs in the feet of platypus. A change in colouration is another physiological adaptation, as it is known that darker colours absorb light and gain heat, better than lighter colours. The Australian grasshopper is able to alter its colour in accordance to the external temperature, allowing it to survive in a greater range of temperatures.