Biology - Regulation of Body Temperature in Animals (Thermoregulation)
Regulation of Body Temperature in Animals (Thermoregulation)
Lizards are ectotherms
Tree frog: the high surface area to volume ratio of its body allows
rapid heat loss or gain.
An optimum temperature is required for enzyme action in cells. Enzymes
become denatured outside their temperature limits. As enzymes control
metabolic activity, their proper functioning is essential to sustain life
processes and to increase chances of survival of the organism.
_Thermoregulation_ basically ensures that heat gain equals the loss of
heat from an organism by convection, conduction, radiation and evaporation
_Thermoregulation_ involves regulating heat exchange between internal and
external environments and, for _endotherms_, controlling metabolic heat
production. Organisms have structural, physiological and behavioural
adaptations to cope with this. _Ectotherms _ depend largely on heat from
their environment to regulate internal temperature. _Poikilotherms _,
such as most fish, are unable to control body temperature - it fluctuates
with the temperature of the external environment.
Heat loss or gain depends on:
* temperature gradient between an organism and its environment - the
steeper the gradient, the more rapid the heat gain or loss
* area of exposed surface in relation to its volume
* effectiveness of any insulating barrier to heat exchange; for example,
feathers and fur which trap air (a poor conductor), and blubber
Elephant: the low surface area to volume ratio of its body limits heat
loss or gain.
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