Another article on the evolution of skin pigment in humans at archeoblog.
the assumption is that humans evolved white skin from tan, but in other articles, it suggests that the skin turned tan in sunny climes as the hair got thinner. But why did the hair get thinner, since monkeys do okay with short hair?
A lot of this speculation is tainted by racism on both sides.
But the faster evolution of lighter skin in northern climates (e.g. Scandanavia, Korea) would be fairly fast due to ricketts.
A couple generations of contracted pelvises and dead moms would lead to a fast evolution.
as for that part about "fish" allowing vitamin D in hunter gatherers?
yes and no.
What hasn't been answered in all of this is clothing.