No source my man, all me.
Here's the first part:
"I would lean towards at least 3: The Men of the North (Euro), The Men of the East (Asian), and The Men of the South (Negro).
I would further suggest designation of The Men of the West, who were separated from their ancestors' lands and became something else entirely.
These were an admixture, of North and East, re-introduction of Northern bloodlines (from Westerly tribes of the North {keep up}) much later generating a sort of duality in their Southern modern populations (due to those from largely South-Westerly tribes of the North); their Northern modern populations, having been largely militarily conquered (by those from North-Westerly tribes of the North {you're keeping up, yes?}) during the aforementioned re-introduction, are extant in comparatively small numbers (~13-14 million in North America).
Three Houses of Man (Euro, Negro, Asian), with a fallen House (American; admixture of Euro/Asian) now largely conquered - whether through blood or iron - by the descendants of its ancestors' cousins (North-/South-Western Europeans)… Other Houses existed once, the Heidel, Neanderthal and the Denisovan, but they too were conquered through blood and/or iron (or, rather more likely, stone).
Humanity is not static, and never has been - gene flow is a fluid-dynamic, moving between reservoirs of variable stability, with variable genes (and associated physiology/psychology/behavior/culture/society) dominating the population (as best suits the selective factors acting upon them at that time).
Are The Men of the South and their derivatives - also known colloquially as "niggers" - human?
Aye.
A Great Dane and a miniature Dachshund are both dogs - but if you were wise, you wouldn't confuse the two as equivalents due to such terminology.
They are not.
Think of it this way: Do you think evolutionary theory is accurate?
Such theory is explained thusly:
If tomorrow we take 100 finches that are genetically equivalent (or as much-so as a group can be) and put them on two islands with differing environments, their genetics - which influences physiology, which influences psychology, which influences behavior - would begin to favor traits which are 'selected for' by their environment and the circumstances therein.
Say, we place 50 finches on an island where the primary food source is pollen from flowers whose structure makes a long, thin beak beneficial; and, we place the other 50 on an otherwise equivalent island where the primary food source is seeds which make a stout, strong beak beneficial.
What will those populations look like, comparative to what we put there, after 10 years of these conditions and emergence of novel selective factors ?
After 20?
50?
100?
500?
1,000?
10,000?
100,000?
Hard to say, but there's a pretty good chance there will be significant genetic - and by extension, physiological, psychological and behavioral - variation between the populations."