If you believe in Adam and Eve, I would say they must be black, because studies of human genetic variation do imply that Africa was the ancestral source of all modern humans. Most races on earth, including Europeans, Asians, and Native Americans, were found to be a single related group resulting from a later out-migration from Africa, which could reasonably be divided into Oceanic branch and Eurasian groups.
Humans are all related. The Eurasian branch split into the Europeans and East Asian branch. Remember, this happened about 150-300 thousands years ago. The Europeans moved North and the East Asians moved East. Because people live in higher latitude will always attempt to have lighter skin color and the Europeans have been living in Europe for so many thousand years, their skin color and facial characters have all changed. That's why there are white people on earth.
Have you seen African Americans whose color is light like brown people? That's because America is generally colder than Africa, and African Americans moved here two hundred years ago. If they live longer (like another ten thousand years), they'll look like brown people (both color and face), and so far so on.
Ok, as I was saying, the other Eurasian sub-branch was East Asians. They divided themselves into two groups: eastern Russians and Eastern Asians. The eastern Russians moved to Siberia in Russia, and the Eastern Asians moved to the Middle East.
The eastern Russians migrated from Siberia across the Bering Strait about 10 thousand years ago and they formed the Native Americans. Then the Native Americans moved south to form the Mexicans.
For the Chinese, they are a mix of the eastern Asians and the Southeast Asians from the Oceanic branch. Maybe that explains why they are smart. All the mixed people I know are smart.
The other group of the oceanic branch, the pacific islanders, moved to Pacifics, that includes Australia, New Guinea, and Hawaii. They formed the Maolis in Hawaii and Australian aborigines.
· 1 decade ago