I'm surprised by how many very intelligent people don't know that humans are originally from Sub-Saharan Africa. It's true! Most of human evolution took place there, even before Australopithecus. In fact, the two Great Apes that are our closest evolutionary cousins (chimpanzees and gorillas) are still mostly in Africa.Also, most fossil evidence of early Homo genus members are concentrated in the eastern parts of Africa. I say "most" because many of them wandered out to parts of Eurasia (i.e. Neanderthals in Europe, Denisovans in Siberia, and Homo erectus in China and India). There are some competing theories about the precise details of the most recent parts of human evolution, but there is an overwhelming scientific consensus that at least the main bulk of human genetic material came from Africa. There is some evidence that other human-like species evolved in Eurasia and then interbred with the African Homo sapiens. Comparing Neanderthal DNA to humans' shows that an estimated 1 to 4 percent of French and Chinese have Neanderthal ancestry.
Just to clear up any confusion: Neanderthals looked almost exactly like modern humans. In fact, they were probably more intelligent since their craniums were larger than ours, implying that their brains were bigger too. They were also much stronger than us, especially in terms of upper body strength. It is unclear why Neanderthals became extinct. One hypothesis is that humans were more aggressive and vastly outnumbered them. When the two came into contact, humans would usually kill them or sometimes absorb them into the human gene pool.
One question: why aren't we all black? Once people started moving out of Africa, they needed to absorb more sunlight since the sun's rays are less intense further from the Equator. If you had too much pigment in your skin (from melanin), you wouldn't absorb enough sunlight to produce vitamin D in your body. If this happens at an early age, you develop rickets where your legs become cross-legged. Thus, natural selection produced people who eventually had fairer skin.
Why does any of this matter? For starters, it's fascinating! We now have a better understanding of where we came from and how we developed as a species. In evolutionary psychology, it is helpful to have a better understanding of prehistoric human conditions and behavior to know how they might have influenced ours.
Secondly, I think this is an important tool in eliminating racism and perhaps nationalism. The fact that we are all of African descent should liberate us from thinking that one ethnic group is better than another. At least, that is the hope.
