That is true as well that you can further break down these concepts and examine isolated pockets of human population to find more diversity in them, especially in age-old sites as with Africa. The longer a population has had time to settle into a region, the more entrenched certain genetic qualities will be - the same you most often see with genetic identifiers that help determine "race". An excellent example would be if you have ever had a genetic survey performed and you saw how they break down what your genetics are made up of. I might be entirely European, as I am, but it further denotes everything from the haplogroup to the line of descent and where those are regionally located; some even cross the species boundary and denote likely markers of relatives early Homo sapiens interbred with.
This only becomes more complicated when you start involving the fact that most people have no idea what their lineage actually is genetically and base it solely off of observation, their own folklore, and imagination. If anything it creates more illusions of what race is when it should really be a matter of what race isn't; ignoring social and psychological biases of course, because humans are anything but simple animals to study.
I suppose the best comparison I have ever heard was a dartboard, where if the board were humanity and you were to throw darts at each block labeled a different race, you are not going to hit every identifier or quality of them that makes them "that race".
This only becomes more complicated when you start involving the fact that most people have no idea what their lineage actually is genetically and base it solely off of observation, their own folklore, and imagination. If anything it creates more illusions of what race is when it should really be a matter of what race isn't; ignoring social and psychological biases of course, because humans are anything but simple animals to study.
I suppose the best comparison I have ever heard was a dartboard, where if the board were humanity and you were to throw darts at each block labeled a different race, you are not going to hit every identifier or quality of them that makes them "that race".