Skin cancer usually occurs relatively late in life, and is not as
important a consideration in selection for darker skin, since
selection tends to favor young organisms over older ones in making
its trade-offs. The more important reason for skin pigmentation is
to protect folate stores from the effects of ultraviolet radiation.
At the equator, extremely dark skin is needed. Moving toward polar
latitudes, the ammount of sun exposure decreases until only a few
months of the year provide sufficent exposure to provide for vitamin
D synthesis, thus people in arctic and sub-arctic latitudes tend to
have extremely fair skin that tans only lightly or not at all. An
exception are the Inuit, who have very dark skin but eat a diet of
95% fish and marine mammal products, which are rich in vitamin D.
There was thus no selective pressure for fairer skin.
--- In
cybalist@yahoogroups.com, "Glen Gordon" <glengordon01@...>
wrote:
> Siglo:
> >By the way, how can you tell he was mediterranean and darker
skinned
> >if the surviving statues have no color any longer?
>
> Ever seen painted pottery before?? Plus, logically, based on
modern
> genetics,
> and given the more southerly locale of the mediterranean, a darker
pigment
> is more likely than near albinoism here. And certainly, even if
anyone was
> really white they'd get tanned real quick in the Grecian sun or
die from
> skin cancer at an early age.
>
>
> = gLeN
>
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