English 1102-Essay 2 Rough Draft
October 14, 2011
“ \=][uldn’t it be great to dose off at work and still get things done?”
Sleep. It is probably safe to say that this is one of the most important aspects of an organism’s life. Sleep allows living things to rest and store energy that will be needed once they awake. If you think about it, sleep does have some serious evolutionary disadvantages. When asleep, you are vulnerable to predation and sudden changes in the environment. Studies have shown that birds and other mammals can sleep with one eye open and one half of their brain awake, a phenomenon called unihemispheric sleep. The Mallard duck is one type of animal that utilizes unihemispheric sleep. These ducks usually sleep in groups. In order to avoid predators while the group is resting, the ducks sleeping on the outside engage in this type of sleep. By doing so, they are able to sleep with one eye open and can detect movement around them on that side of their body. A Mallard will keep the eye facing outside of the group in a semiconscious state for the benefit of the group as well as themselves. What is unique is that they are able to control it. They can also sleep with both halves of the brain. When they are sleeping under more risky situations, they increase the proportion of their sleep with one eye open and half their brain awake. They are able to make behavioral decisions about whether to keep one half of the brain awake or allow both to sleep.
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