linucs

I'm referring to the human race evolving in the African continent and then migrating to the rest of the world.

Evolving in Europe made people light skinned to account for the reduction in sunlight exposure, are there any other traits which other ethnicities developed to adapt to their new environment? Or are the diifferent traits in different ethnicities just stuff that developed by chance and got somehow reinforced because of the isolation between populations?

This question came to my mind first thinking about "Asian eyes", do they serve any "purpose"?

Alternative title: Dinosaurs wouldn't be that big if they weren't that big

Any topic, just explain what it is please

I know evolution is governed by chance and it is random but does it make sense to "ruin" sleep if there's light? I mean normally, outside, you never have pure darkness, there are the moon and stars even at night. In certain zones of the Earth we also have long periods of no sunshine and long periods of only sunshine.

I don't know if my question is clear enough but I hope so.

Bonus question: are animals subject to the same contribution of light or lack of it to the quality of sleep?

This is something I always wondered because some people have a bunch of theories about whether your head should face north or south or whatever, because of the earth magnetic field. Is there any science in this or just "superstition"?

Also, would it be better to have the head towards a window or away from a window, even if closed (e.g. in winter)?

I'm basically asking whether there exist "recommendations" on how to structure a bedroom backed by science.