As you move northward from sub-Saharan Africa, human skin color becomes progressively lighter...?

As you move northward from sub-Saharan Africa, human skin color becomes progressively lighter. Explain that observation in the context of vitamin D synthesis and folic acid metabolism.

As you move northward from sub-Saharan Africa, human skin color becomes progressively lighter...?
All I can say on the topic. The further north you go the more likely you'll have less skin exposed to sunlight. People wear clothing to keep themselves warm. Skin colour must pale so that your body can absorb more sunlight to manufacture vitamin D.





Most of us now are walking around in t-shirts and shorts, but try doing that naked, it gets cold fast...
Reply:because of natural selection, certain genes that coded for skin pigments became more common in certain areas. vitamin D and folic acid must control this for some reason?
Reply:maybe it depends on the amount of light received by that area....with more sunlight there would be more of those stuff( i don't remember what it's called....forgot after my exams)...hey wait i remember...its called something...melanin pigment or something...so those stuff are more in number....the colour of the skin is darker........these pigments are produced and maintained with the help of vitD which is received from sunlight....and the amount of light decreases as we move away from the equator....i can't explain in more detail...
Reply:If you look at the climate in sub-Sahara, you'll notice a very hot day and a very cold night; this is due to long sun exposure to that surface of the earth. As you move northward in Africa, the climate is more Mediterranean, steady temperatures and much less sunlight. Therefore, after thousands and thousands of years, the people of sub-Sahara region most of whom are Tuareg (AKA blue men) have a much darker skin but don't have the facial physionomy of black African, such as nasal cavities, cheek bones, lips, and so on. This also implies that the very North of Africa has mostly Caucasians, a lot of whom are blonds blue eyed people, having the exact look as Europeans.


I hope this helps :)