Friday, April 15, 2011

Hairs

The human body is covered by hair apart from the palms of the hands, the lips, certain areas of the genital structure, or the soles of the feet. Hairs extend the sense of touch beyond the surface of the skin and provide thermal regulation. Nowadays it seems that hairs exist only to be removed. Hair removal is a common procedure in beauty salons and this can be done there by laser hair removal for example while shaving still being the most used method.

It has been tried to explain the hairlessness of humans, as compared to other species. The thermoregulatory hypothesis suggests that when human ancestors started living on the hot savanna, humans began to sweat more to stay cool. It is posited that hair got in the way of the sweat evaporating, so humans evolved a lighter coat of fur. Although hair provides protection against UV radiation, only our heads were exposed to the sun and thus humans kept the hair on our head, but our body hair was reduced. The aquatic ape hypothesis posits that sparsity of hair is an adaptation to a semi-aquatic environment. And one hypothesis is that human hair was reduced in response to ectoparasites. Getting rid of our hair might have reduced the risk of fleas, ticks, lice, and other biting insects.

One interesting thing about hair removal is that road cyclists tend to remove leg hair for a number of reasons: In the case of a crash, the absence of the leg hair means the injuries (usually road rash) can be cleaned up more efficiently, and treatment is not impeded.


7 comments:

  1. Most evolutionary biologists say that the lack of hair in humans can be attributed to sexual selection, ie. you probably don't find hairy women attractive.
    Cool posts though. Keep it up.

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  2. C.W.Brady thats a great point of view mate!

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  3. I'm still hairy as an ape here.

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  4. ive always been taught in school that we dont have hair cause we started wearing clothing and didnt need it

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  5. monkeys have hair everywhere except for the genital area. we have hair (almost) only in the genital area. evolution, you suck!

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