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  Topic: VMartin's cosmology, where he will not be off-topic< Next Oldest | Next Newest >  
Steviepinhead



Posts: 532
Joined: Jan. 2006

(Permalink) Posted: Sep. 20 2007,13:31   

Dark skin (lots of melanin) folks, prior to the last few several hundred years of exploration, colonialism, trade, and technology, lived in low latitudes with lots of sunlight, where protection from skin cancer would have been the primary selection pressure.

Lighter-skinned folk, prior to etc., lived in higher latitudes, with less incident insolation, where dark skin would not only not confer an advantage, but would tend to inhibit the formation of Vitamin D.

(I'm hoping you know what Vitamin D is, and why its absence might be a problem.)

Folks with medium tones (Mediterraneans, Asians, Native Americans) tended to live in intermediate latitudes.

The Inuit (and some people pursuing similar lifestyles in far north Asia) lived so far north that they were exposed to sunlight reflected off snow and ice for much of the year.  (You may never have spent a sunny, or even cloudy, day on a glacier absent eye and skin sun protection, given that you apparently live in some basement in Lower Trogdylvania.  If so, I wouldn't recommend the experiment: sunburned tongues, inner nostrils, roofs of mouths, and eyeballs isn't too healthy.  Eh, on the other hand, go ahead, give it a whirl, Mr. aposematics--it's no skin off my nose.) They were, again, somewhat darker-toned.

Are you beginning to see a fairly simple relationship between latitude, sun exposure, and degree of melanin in the skin, Vmaroon?

Eh, probably not.  Anyone else could've googled up a latitude/skin tone chart in about 30 seconds, before so blatantly exposing their ignorance.

And, humor-deafness.

  
  494 replies since Sep. 06 2007,12:29 < Next Oldest | Next Newest >  

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