Evolutionary explainations of sleep

Evolutionary explainations of sleep

1. The evolutionary theory of sleep suggests that there was osme evolutioary advantage to sleeping, other than to restore us.

2. Predator-prey sleep; Meddis (1979) believes that sleep evolved to keep animals hidden from predators when usual activities, like forgaing are not required. Those who survive are able to pass on genes.

3. Hibernation theory; Webb (1982) beleives that active animals need larger amounts of food, threatneing survival during times of food scarcity. Hibernation conserves energy thus increasing survival.

   • In support of this; Stear (2005) reported that sleep saves energy, keeps individuals from being lively at unnecessary times and is an adaptation to ecological factors differing across species, supporting the evolutionary basis of sleep

4. Foraging needs; animals which eat food containing few calories, like grass, need to eat more an dfor longer and so would have to sleep less to survive and pass on genes. Animals eating calorie rich foods could afford to sleep more as they would not need to eat all the time

5. Aquatic mammals; the precise enviromental demands of species affect sleep patterns and behaviours. Aquatic mammals need to breathe, so sleep incurs a rise of drowning.

6. Body size; smaller animals evolved a greater need to sleep, their metabolic rates being high and energy consumption rapid. Long periods of sleep helps to consever energy stores.

7. Requadt (2006) found that animals locate warm, safe places to sleep as it minimises energy requirements to maintain body temperature, supporting the evolutionary point of veiw

8. Alison and Cicchetti (1976) studied sleep patterns in 39 animal species. They found that prey species were likely to spend only short amounts of time asleep which disagress with Meddis' theory of predator avoidance. However, prey animals are usually herbivores and would require to be awake for longer in order to find enough food.

9. Siegal (2008) reported that there is a less risk of injury when asleep than awake, sleep being a safety device when essential activities are not requires.

10. A lot of research involving evolutionary explainations depends on animals studies, incuring a problem with generalising animals to humans