In the evolution of humans:?

Question

What is the theory behind the development of different races? Was the "first human" dark-skinned or light-skinned?

What is the genetic background of the shift of characteristics?

(Just cold, scientific answers please: I am not asking a religious question although I respect that people have religious views and their right to hold them: please assume I already know these theories)

does anyone have any references for these theories?

Answer 1

There is considerable evidence that the first humans evolved in Africa.

Race is not synonymous with skin color ... in fact, the word "race" doesn't have much meaning at all in Biology. Anywhere there are humans, they are all interbreeding with neighbors ... so there is a continuity of genetic characteristics from one region to the next, right around the world ... it is only when we compare people from two distant regions that we notice a diffference.

As far as skin color itself, this is directly related to the kind of sunlight experienced over many generations. The longer your ancestors lived in open sunlight near the equator, the more they will tend to have more melanin in the skin, which adds protection from harmful UV rays. This needs to be considered together with migration history and other environmental factors ... for example, in the Americas, while it is still true that people living near the equator have darker skin that people in the far north or southern hemisphere, humans have not occupied the Americas for nearly as long as in Africa and Australia. Also the equatorial environment in South America provides a lot more shade than the equatorial environment in Africa.

Answer 2

What others are saying about darker skin protecting agains UV rays is correct.

But, it didn't just "happen" that as people moved farther north their skin became lighter. It was a necessity because people get vitamin D from sun exposure. In the more nothern areas, there wasn't enough sun in winter to be absorbed by dark skin so the lighter the skin, the more people who survived to pass on their lighter skin to their offspring.

This was noted very recently in Afghanistan where women under control of the Taliban were (are?) never allowed to go out of their homes without being covered in black from head to toe. Those women develop vitamin D deficiencies because they never see the sun.

Answer 3

The first pre humans were dark skinned and hairy because they evolved in a hot climate (Africa). Later on when Homo Erectus migrated North and entered Europe, the climate was colder and there was nowhere as much sunlight, they no longer need the deep skin pigmentation because it was no longer a survival factor and gradually was bred out.

Answer 4

from what I remember in Evolution courses, there is actual proof that we all came from a Dark Skinned person. Scientifically it makes sense as far as genetics go. As our gene pool got larger it made room for mutations... and such

Answer 5

Seems to me that an upright biped named Eve was discovered in Africa.. She was our first known ancestor. If you think we "evolved" then Africa was our place of origin. Seems that nature would have protected our "evolving" ancestors with lots of melinin in our skins to protect us from the sun.

Later, as we spread and we did not need the darker skin, we began to lose the pigment. .......like Cro-Magnon in the caves of France

Course lots of people believe that God scooped up some dirt and breathed life into it and created man"in his own image" My dog ain't in that fight.

"Shoot low, they're riding Shetlands."

Answer 6

The first human was light skinned, and as they adapted to hotter climates, their skin went darker.