Biological Rhythms 3

Outline the evolutionary explanation for the function of sleep.

Sleep is adaptive because it allows us to cope with the environmental pressures that we face. It has 3 main principles. Firstly, it allows us to conserve energy. Secondly, it allows prey to be protected from predators and thirdly, it is constrained by the time taken to forage and feed. Prey sleep less because they are on guard whereas predators sleep more because they are less prone to danger. Webb explains that sleep allows us to conserve energy because there is an increased risk of accidents at night which we avoid when sleeping and also because foraging and feeding is harder during the night anyway. 

Outline the restoration theory for the function of sleep.

Restoration theory suggests that sleep allows the body and brain to recover from the day's wear and tear. Slow wave sleep allows for brain growth to occur. This is because during sleep, the pituattry gland releases a growth hormone which stimulates protein synthesis which stimulates tissue repair. Also during sleep, we brain repair occurs because the neurones in the brain can restore sensitivity to neurotransmitters.