colour questn

[de$per@do]

why people living in cold weather are white in colour?? and that of in hot weather are black in colour????
lyk European american etc are white and african are black in colour

[Borek]

It is not temperature, but amount of Sun light.

http://en.wikipedia.org/wiki/Vitamin_d#Production_in_the_skin

[DaveC426913]

Not sure how vitD plays in to skin colour.

Read up on melanin (http://en.wikipedia.org/wiki/Human_skin_color). It is a pigment in the skin that, among other things, protects us from UV radiation. More sunlight means more risk of damage from UV, so the body produces more melanin. End result: a people in sunnier climes have darker skin.

[Borek]

Not sure how vitD plays in to skin colour.

Combine dark skin and lack of light for half a year... Lack of melanin is an adaptation.

[DaveC426913]

Combine dark skin and lack of light for half a year... Lack of melanin is an adaptation.

Ah, I see.

Related true. But I didn't actually read anything in the vitD article that mentioned skin colour. The missing puzzle piece is melanin.

[cosmos 2.0]

when homo sapiens evolved they were exposed to a lot of uv rays in africa. Once they migrated to higher latitude the reduced amount of uv rays meant that humans had to adapt to these conditions which means less melanin (eumelanin) - light skin color

Europeans do produce melanin, just a different kind - pheomelanin

http://en.wikipedia.org/wiki/Human_skin_color (http://http://en.wikipedia.org/wiki/Human_skin_color)

http://en.wikipedia.org/wiki/Melanin

[nismaratwork]

Quesstion: beyond the change in location, did the amount of clothing required to live in northern climates play a role beyond just exposure to UV in general? After all, if you're swaddled in skins and furs, it's a bit of waste pumping out all of that melanin, but if you're in the savannah, it pays not to have to use as much clothing and depend on your skin tone.

[cosmos 2.0]

Even clothing and food would have played an important role. Maybe inuits (natives) in Alaska have darker skin due to their diet rich in vit d.

Question - can anyone give ideas - why natives(aborigines) in Australia are dark even though the southern part of australia, even tasmania has a temperate climate ?

[DaveC426913]

Maybe inuits (natives) in Alaska have darker skin due to their diet rich in vit d.
I alwys figured it was because they are a relatively recent migration to the area.
But you're right; they wouldn't have been able to migrate into the area (and survive) without some sort of adaptation for getting enough vitD.

[cosmos 2.0]

I always figured it was because they are a relatively recent migration to the area.
But you're right; they wouldn't have been able to migrate into the area (and survive) without some sort of adaptation for getting enough vitD.
I was under the same impression, but they migrated from a similar latitude across the Bering strait (at least that's the theory) which means they were in similar conditions on the other side of pacific(and for how long were they there?).
I do not have any references for these.