What are the two evolutionary theories of the functions of sleep?
the hibernation theory and the predation theory.
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What is the hibernation theory?
this states that sleep gives a survival advantage as it conserves energy. energy usually used in keeping warm and other activites is conserved, this is because when we sleep our body temp drops and so does our metabolic rate.
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what is the predation theory?
this suggests that the amount of sleep an animal gets is determined by its exposure to predators and its need for food (metabolic rate)
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How would the predation theory explain the sleepin pattern of a shrew?
a shrew is at high risk of predation and therefore it is difficult to find a safe place to sleep, it also has a high metabolic rate which means it need to eat frequently in order to keep up its energy levels. a shrew would sleep very little
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What is a relevant IDA point for these theories?
biologically determinist
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why are the theories biologically determinist? (IDA)
they suggest that the animals with the best sleeping patterns would have survived as consequently it has become a genetic factor in our sleep pattern.
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what research contradicts the theories and what might be a better approach? (IDA)
sleep deprivation studies contradict the theories and a biological approach such as the restoration theory may be a better explanation.
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Name three pieces of research for this explanation
Alison and Ciccheti, hibernation in animals and sleep deprivation studies.
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What did the research by Alison and Ciccheti find?
when they analysed the sleep patterns of 39 different species they found a relationship between the risk of predation and the amount of sleep they got. animals at high risk or predation slept very little compared to animals at lower risk of predation
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Which theory does the research by Alison and Ciccheti link to and how?
the predation theory, it shows how animals more at risk of predation (prey) cannot afford to sleep for very long whereas the predators can sleep for much longer as they are at much less risk.
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What does the hibernation research show?
in the winter when food is scarce and temperatures drop some species hibernate.
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which theory does hibernation link to and how?
it links to the hibernation theory, it shows that animals sleep in these conditions in order to conserve energy as there is a lack of food to supplement their stores.
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What were the findings of the sleep deprivation studies?
Peter tripp - awake for 8 days suffered hallucinations, delusions. Randy Gardner- awake for 11 days, suffered blurred visiona and disorganised speech. Michael Cork suffered from fatal familial insomnia, usually die between 7-36 months from onset.
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How does the sleep deprivation research contradict this approach?
they show that we need sleep for normal cognitive functioning and that prolonged lack of sleep can cause death. ultimately showing that sleep has a bigger role than just to conserve energy and keep us safe from predation.
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What is there generally a lack of regarding this approach? (AO3)
there is a lack of experimental research.
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What is an issue with the Alison and Ciccheti research? (AO3)
it is a correlation, you cannot establish cause and effect between risk of predation and the amount of sleep.
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What is an overall issue with the approach? (wider evaluation)
it cannot give a complete explanation for the existence of differing sleep patterns.
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What would a better theory be able to do? (wider evaluation)
a better theory would address why we sleep and how biologically it effects us.
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Other cards in this set
Card 2
Front
What is the hibernation theory?
Back
this states that sleep gives a survival advantage as it conserves energy. energy usually used in keeping warm and other activites is conserved, this is because when we sleep our body temp drops and so does our metabolic rate.
Card 3
Front
what is the predation theory?
Back
Card 4
Front
How would the predation theory explain the sleepin pattern of a shrew?
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