so we all know the basic idea that UV, sunlight, and vitamin D concentrations are responsible for the general changes in skin tone in people living from the equator to the poles…but this is a really interesting article about why northern europeans are even more different than everyone else–light hair, blue eyes, even paler skin–and the science behind it:
Why Are Europeans White? (E1)

i know most of you are lazy and probably won’t read the whole thing so here’s a good summary:
The Baltic is the only place on earth where ocean currents keep it warm enough to grow grain despite dim sunlight.
When the inhabitants of this region switched to grain about 6 KYA, they suddenly got insufficient vitamin D to survive. They had stopped eating mostly meat and fish in a place where sunlight was too dim to produce vitamin D in normally pigmented skin.
And so they adapted by retaining into adulthood the infantile trait of extreme paleness. Blonde hair and blue eyes were other infantile traits that were just swept along accidentally.

Tags: agriculture, eye color, hair color, interesting, neoteny, science, sunlight, uv