How many generations does it take to change skin colour.

[Tiocfaidharla2012]

Well, I was thinking about the lie about "white people turning extinct" that racists loves to toss around by exaggerated statistics, etc... (Which, even if they WOULD be true, only would mean that whites is becoming a minority because other ethnical groups is having more children than white people, not that white people are actually getting fewer.)

And then I thought, that if one million people with black skin would be forcibly moved from Congo to, let's say Iceland, and the Icelanders living there would be moved to another country, how many generations roughly would it take for the black people's skin to adjust to the environment and turn white? I know that it would happen, but roughly how many generations would it take?

Also, I am wondering if they would see any other changes, like would parts of the group's eye or hair colours change after enough time?

And, would it take longer or shorter time if it was people with other skin colour than black? I know that many Afrikaans living in South Africa still have light skincolour even after their ancestors has lived there for centuries.

So yeah, tl;dr: I'm wondering if there's any scientific answer to how long the process would be for a group to change skin colour due to living in another type of climate, if there's only people from their own skin colour living there?

[Black_Rose]

One; Sammy Sosa did it.

[RedHammer]

That depends on a number of factors. Evolutionary change can occur through many different mechanisms: natural selection, sexual selection, genetic drift, and so forth. Skin color, and other racial characteristics, may have evolved according to any combination of these mechanisms.

In order to determine how long it takes for these changes to take effect, you could determine how long ago the "most recent common ancestor" of all human beings lived. Splits along the "human family tree" may correspond to racial differences. You could examine this. But this is a difficult task, for a number of reasons: firstly, what exactly is race? And how do you clearly distinguish one race from another? And, of course, there's the fact that some ethnic groups may be more closely related to others than to some others, still.

Race is almost entirely a social construct that has little basis in reality. The only difference between "races" is the cosmetic difference, but that's hardly clear-cut.

All human beings alive today may have had a most recent common ancestor as early as 40,000 years ago. That's long enough to facilitate cosmetic changes, but certainly not long enough for there to be functional differences between the races. I can't give you a precise answer because the changes were surely apparent long before civilization was even established.

At any rate, don't bother debating racists. You can shove all the facts in their face and they'll still cling to their near-religious faith in their "race".

[Luís Henrique]

And then I thought, that if one million people with black skin would be forcibly moved from Congo to, let's say Iceland, and the Icelanders living there would be moved to another country, how many generations roughly would it take for the black people's skin to adjust to the environment and turn white? I know that it would happen, but roughly how many generations would it take?

It wouldn't happen. Or it could happen, but only if there was a mutation for fairer skin (that had no harmful other effects). How much time until such mutation would occur? Impossible to know.

If there were residual genes for fair skin within the supposed all-Black population, those genes would eventually prevail, because of evolutionary advantages (better absorption of vitamin D) of fair skin in the climatic conditions of Iceland.

Luís Henrique