The Effects of Maintaining a High Constant Body Temperature in Mammals

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The Effects of Maintaining a High Constant Body Temperature in Mammals Endothermic organisms maintain a stable core body temperature through their own adapted physiological mechanisms and appropriate changes in its behavioural patterns. The ability of an endotherm to keep its internal environment at a constant temperature allows the enzymes catalysing the vital biochemical reactions to be close to their optimum temperature, giving an efficient metabolic rate. The metabolic rate is defined as the rate at which all the cells in the body carry out their biochemical reactions. This constant high metabolic rate allows the endotherm to produce rapid movement in colder regions. For example the ability for the body to respire quickly when faced with the fight or flee situation, under the influence of the hormone adrenaline. This high metabolic rate aids in the maintenance of the high core temperature, however as most of the heat is generated as a by-product of respiration large therefore vast quantities of food must be consumed. µ Herbivores consume plants, which are relatively low in energy and must therefore devote a large portion of their day to eating if they are to maintain this high metabolic rate and internal environment µ Carnivores consume food which contain much higher levels of energy and as a result they eat less often In the short term, a change in temperature is detected by the temperature receptors situated in the hypodermis layer of the skin. These transfer a signal to the hypothalamus in the brain, which uses negative feedback to rectify the change. Initially the hypothalamus triggers the higher centres of... ... middle of paper ... ...the ground may reach as cold as 0oC, at this temperature the biochemical reactions occurring in the body of the lizard would be so slow it would run the risk of dying. As a result the lizard must find a warmer location so spend the night, usually it has a burrow it can retreat to when it gets too cold. The burrow will usually remain at a constant temperature of approximately 20oC; conditions the lizard will be able to survive. Lizards will also adjust their body position so when heat needs to be absorbed from the surroundings it is done in the most efficient way, by placing themselves at right angles to the direction of the rays. Despite these behavioural adaptations most endotherms are ill suited to living in colder climates, as there is insufficient energy available to maintain a suitably high metabolic rate.

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