The above website hosts an excellent article on why human races don’t
have a biological basis, namely stating that “human population diversity
is too subtle to be placed in arbitrary geographic groupings, or
‘races'”. For example, in China the farther north you get the more
shoveled the people’s teeth become, whereas the farther south you get
the less shoveled the people’s teeth becomes. Africa also has the
world’s highest genetic diversity, which is something we’d expect if the
Out of Africa hypothesis was true, and that is what we find. Indeed, if
we use genetics as a basis for “race” West and East Africans would be
completely separate races.
Instead of race we should focus more on ethnicity, or clines, which
better fit human population diversity. Examples of clines including the
Irish, the San Bushmen, and Fijians. There’s a reason Africa is home to
the most genetically diverse people on the planet, and it ain’t because
of Adam and Eve.
This is not to say that there aren’t any genuine differences between the various human populations, there are, but the concept of there being distinct “races” within our species doesn’t cut it, it’s bullshit, and in fact is an impediment to better understanding of the evolutionary history and population biology of our own species, Homo sapiens.
An even better model to use when modeling human populations is the concept of the demes, or “breeding population”. A standard breeding population is around 25,000 people, in which people are more likely to breed within their demes than without, a good example of a demes today would be the Amish. An ethnic group such as the Han Chinese aren’t a demes, they consist of one billion people and have multiple demes within their ethnic group.