Why aren't all Americans the same color if living in a certain region is said to change skin color?

Question

Why aren't all Americans the same color if living in a certain region is said to change skin color?

Answer 1

It will change skin color - in thousands and thousands of years.  Be patient.

Answer 2

First of all, Americans have genetic backgrounds from all around the world.  Somebody whose grandparents moved here from Finland will obviously look different than somebody whose grandparents moved here from Borneo.  Apart from that, we have not been here long enough.  America has been its own country for about 250 years and (apart from the Native Americans), people have been immigrating here for about 400 years.  It takes thousands and thousands of years without drastic amounts of immigrint genes within the population for all Americans to even *begin* to look the same.

Answer 3

Well there is a lot of people here from different countries. And a change like that (previous answer said) will take a lot of years.

Answer 4

It takes tens of thousands of years. There are rock paintings in Spain that depict dark humans. 300 years doesn't quite cut it

Answer 5

Two missing ingredients to make that happen:

A. Time - Today's "Americans" haven't been here nearly long enough

B. Isolation - with a steady influx of new arrivals there's new genes from around the world entering the gene pool every day

Answer 6

becuz not every1 has the same genetics and some ppl might be immigrants.  

Answer 7

Because "Americans" have only been here for a few hundred years with a lot of people coming in (or different colors). It take a long time in a segregated poopulation.  

Answer 8

Humans are not chameleons, evolution of the type you imply, takes millennia.

Answer 9

Susan P is correct.  A conservative estimate is that it takes 25,000 years for the skin color to adapt to UV levels in a given region.

Answer 10

there is this little thing called genetics.