Sunday, September 29, 2013

so why sleep?

Earlier I thought it was because of the earth's rotation, and day-night cycle. But then I realized, the very first animals evolved in the deep oceans where sunlight was devoid.

What then could the reason be?

Actually at this point of time its very difficult to theorize because we don't have a proper scientific understanding of how sleep happens to other species on earth. When we sleep we become immobile. We don't have a sense of touch or any normal audio that is going on around us. Its as if our brain shuts down its vital functioning.

We know what lack of sleep can do to us. It can cause disorientation, make us less-responsive to normal auditory stimuli, and, many other cognitive problems. These patterns of problems can be observed on other species too. There are species of fruit flies which were subjected to experiments which disrupted their normal "rest cycle". It was found that fruit files which did sleep were able to locate food faster, whereas those that didn't get enough sleep couldn't find it fast enough.

There is an evidence that sleep is necessary for proper development of the body as well as the brain. The brain tries to repair connections or even make new ones after it "shuts down". So I suppose this is why infants spend most of the time sleeping.

But how can we explain it in terms of evolution and natural selection?

I suppose the answer to that can be formulated as follows:

Growth or development in any life form is a natural process. But I suppose a "rest phase" is necessary here, because that ensures a healthy development. Any life form in its normal growth or development, if it does not have a "rest phase", its doomed to fail and will be less capable of surviving long enough. And being awake does need more energy, and more maintenance.

So now you can bring natural selection into the solution. So those species which took to this pattern of growth and development survived and flourished.

You may very well ask, there are animals that don't have brains; do they require sleep?

This is almost like suggesting that the brain is the organ responsible for sleep. If so why don't our brains go to sleep keeping all other functions working as necessary? I can't imagine how a human would be in such a condition. But the general understanding should be, if the brain "rests" so does the body. One or the other organs need functioning, others don't. For e.g. our muscles don't need to move so much so they are relaxed.

To a degree this is a kind of symbiosis. This kind of a symbiosis is necessary for healthy living and also to minimize energy consumption.

I really have quoted articles I've read, or videos I've seen on the subject. Research in sleep is still in a study and observe phase. Scientists have not extensively studies "sleep" in other species like they have done on their own species.

However, often I do come across articles and they will be tied to this blog post, as and when I come across some interesting articles. You can find a list of artefacts tied to this article below:

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