Evolutionary Theory Of Sleep Essay

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The four main evolutionary theories can be used to explain the function of sleep which consist of energy conservation, food requirements, predator avoidance and Meddis’ “waste of time” hypothesis. These theories attempt to explain sleep as an adaptive response which increases the chances of survival.
Sleep can be used to conserve energy over long periods of time as metabolism and body temperature decreases. This can be observed in sleeping animals especially in those hibernating during the winter. Furthermore, warm blooded animals such as mammals must use a lot of energy to maintain a constant body temperature. This is more problematic for small animals such as squirrels with high metabolic rates as they use even more energy and hence, sleep
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He suggested that sleep can help animals avoid predators when they are in vulnerable positions especially during the night and “waste time” as they have nothing to do. Siegal et al concurred with this view by arguing that being awake would be riskier due to the increased exposure to predators and the possibility of injury. He used a little brown bat to illustrate this point as it was only awake for a few hours every day to feed and reproduce if necessary, before returning to sleep. This supports the evolutionary theory of sleep as it suggests that sleep aids in survival and reduces energy …show more content…
Evolutionary approach cannot explain why animals have such a strong drive for sleep when sleep deprived. Horne et al suggested that some elements of sleep are for restoration purposes whereas other aspects help in occupying productive hours particularly in smaller animals to conserve energy. He proposed the distinction between core and optional sleep. Core sleep is equivalent to slow wave sleep and the essential portion of sleep needed for restoration of the body and brain processes. Optional sleep such as rapid eye movement (REM) and some portions of non-rapid eye movement (NREM) sleep are dispensable and occupies unproductive hours and conserves energy. However, restoration theorist argue that the link between REM and brain development suggests that REM serves a purpose beyond simply “wasting

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