I'm guessing this has occurred to most people at some point or another, although maybe it hasn't given my very tenuous and inaccurate grasp of what an ordinary human mind is like.
Doesn't it seem like evolution is ridiculously precise? Like, ridiculously? I've been wondering for a while about what the evolutionary purpose of human hair was, especially given how it's so localized to the head and the crotch. The crotch makes a lot of sense for logistical reasons we won't get into here, but the head is just confusing. But then I realized this morning that it was there for a practical purpose- protecting the head from sunburn. The reason for the color of hair is melanin, which is the pigment in the skin that protects from sunburn. That's a beneficial trait for evolution to give us, yes?
But the corollary of that would be that an entire segment of the human population would have to have been wiped out because they weren't well adapted to something that would kill a bald person. I can't think of anything that would only kill bald people except for a serial killer who only killed bald people.
This leads me to speculate that there was an evil, bald child-abusing caveman in the Great Rift Valley, and that two things happened as a consequence. First, his own child was turned sociopathic by a traumatic upbringing and went on to kill all the prematurely bald people before they reproduced. Next, his other victims forced early cavemen to select for genes that made us associate baldness with creepy child molesters and cartoonish supervillains.
Also, I just realized that having hair on our head protects us from UV rays which give us skin cancer, which is probably a much better explanation than the one I just suggested. But I don't think we should rule out my hypothesis just yet.
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7 years ago
3 comments:
I think I read somewhere that baldness was originally created in evolution as a way to show maturity in males ready to reproduce.
However, it ain't going anywhere just like all the other quirks humans have that probably would vanish in other species. Our lives are too easy and there's nothing that would force us to adapt.
Unless, of course, we could evolve the ability to sprout money from our stomachs.
The UV explanation makes sense. It might also be that hair is to keep the head warmer in colder climes and at night. The head loses more heat than any other part of the body.
The thing about evolution, though, is that not everything necessarily has a survival value. Natural selection does happen, but so does sexual selection, and random acts of selection as well (say, for example, the bald tribe of the human race happened to live in close proximity to volcano prone to pyroclastic flows).
Personally, it's not head hair that strikes me as bizarre, it's a lack of hair elsewhere.
Come to think of it, skin cancer was never a problem until people started living into their fifties and upward, and once there was good enough healthcare that other ailments wouldn't get people first. Twenties and thirties were essentially the limit for millenia.
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