Functions of Sleep

Evolutionary Epxlanations of Sleep: The evolutionary theories suggest that sleep is an adaptive purpose and is important to survival. Sleep being a part of every species means that sleep is clearly an essential behaviour however for different reasons for each animal. Sleep is a core function that animals adapt to their own environment.

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  • Created by: natcur
  • Created on: 19-04-16 10:31
ENERGY CONSERVATION- WEBB
Web believes the purpose of sleep is energy conservation. This works by ensuring that the animal is inavtice when it is innefficient to be awake. Webb suggests that there are energy costs for animals to be awake.
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Warm Blooded Animals
Warm- Blooded animals need to spend alot of energy to maintain a constant body temperature. This is perticularly problematic for small animals with high metobolic rates such as mice who need more sleep to conserve more energy.
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Animals Adapted to DAY TIME activity
Animals who adapted to day time activity and eating during the day would be wasting energy by being awake at night when they would be unable to eat. In each case sleep occurs when the animal is least effective.
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Webb
Hibernation theory
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Empson
Empton states that animals are simply biding their time until the environment is more suitable so the function of sleep is to 'waste time'. Sleep therefore surves the purpose of providing a period of enforced inactivity much like hibernation.
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EVALUATION: SUPPORTING RESEARCH: Zeppelin & Rechtschaffen
Found that metabolic rate and animals size did relate to time sleeping in many species. They found a negitive correlation with smaller animals sleeping longer than larger animals. This supports the veiw that high energy conserv might be the reason.
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Role of Animals in Research
One issue with the use of animals in research is sleeping behaviour in captivity may not be the same as in the wild. Giant sloth sleeps 6 hours more in captivity because they dont have to forage for food. May not give accurate research.
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Is Rest as Adaptive as Sleep
Energy conservation in sleep is minimal, reducing energy rates by only 5-10% compared to rest. This suggests that rest would be as adaptive as sleeping. The risks associated with sleeping would seem to outweigh the marginal advantage of energy cnsv.
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Is Rest as Adaptive as Sleep- Continued
This means that the energy conservation explanation isnt sufficient to explain the function of sleep.
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Correlation:
Correlational rather than a casual relationship between sleep and energy conservation.. It can also be difficult to disentanle correlations between sets of variables. Small animals sleep more than large ones but this may not be associated with body.
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Correlation:
But more likely that small animals tend to have saver sleeping hiding places to stay safe when they sleep so therefore they can sleep for longer knowing they will be safe. We cannot say for certain which of these is more important in determining.
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Role of NREM and REM:
The evolutionary theory of sleep cannot explaining why we need both REM and NREM. For example, in terms of energy conservation, only NREM conserves energy as the
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Role of NREM and REM:
bodys physiological processes slow down. In REM energy consumption is only slightly less than waking behaviour with the brain still active. This is supportedby studies which show lager animals have less NREM demonstrating NREM is important for energy
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Card 2

Front

Warm- Blooded animals need to spend alot of energy to maintain a constant body temperature. This is perticularly problematic for small animals with high metobolic rates such as mice who need more sleep to conserve more energy.

Back

Warm Blooded Animals

Card 3

Front

Animals who adapted to day time activity and eating during the day would be wasting energy by being awake at night when they would be unable to eat. In each case sleep occurs when the animal is least effective.

Back

Preview of the back of card 3

Card 4

Front

Hibernation theory

Back

Preview of the back of card 4

Card 5

Front

Empton states that animals are simply biding their time until the environment is more suitable so the function of sleep is to 'waste time'. Sleep therefore surves the purpose of providing a period of enforced inactivity much like hibernation.

Back

Preview of the back of card 5
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