there is no difference in what exactly?

There is no differences in races, people just turn out looking differently because of where they live. It's all cultural--people are going to be culturally different because they live in that area, but that doesn't make them different breeds.
We were all from the same place, we just moved to different locations. So we had one culture and moved and created different, but still similar cultures.
I'm not racist in the least. People are people, regardless.
I highly dislike the black culture in America. I'm not going to lie. Not all black culture mind, but what goes on in my particular area (South East)... all the 'gangsta' speak and pants to the knees, and all that bull... not to mention the Ebonics. OH MY GOD THE EBONICS. I feel like shooting puppies when I hear some of the people around here talk. They sound like idiots, they look like idiots, and I don't have them because they're black, but because they're idiots.
I have black friends that don't act that way, I like them just fine. I hate idiots.
...white idiots too. I really dislike a lot of the white people here too. ...maybe I just hate people in general. x.x
And as to the adaption thing, I've always thought that we were like geckos. Adapting through the generations to our different climates and areas. If you take a group of geckos and put them on an island that they can survive on with a bit of adaption, they'll adapt, and eventually break into sub-species that aren't seen anywhere else, because of the new location. Pretty neat. =3