Darwin used his now famous/infamous quote: "Natural Selection" in a the 19th century to imply the opposite of what men and cattle ranchers did in his time; people would chose male/female animals in the best physical stamina and then mate them with each other. In Darwin's time (Before DNA was known), Men would choose as an example - the healthiest Bull to mate with the Healthiest Cow. In Darwin's mind, species would have had to done this on their own in order for his Theory to be correct. So "Natural" refers to animals instincts and self will from millions of years ago and "Selection" the pair whom they choose to mate with in order to continue their species.
So for example: Man comes from "Apes" yes, but it's not so much the "Ape" than it's predecessors of millions of years before. Evolution teaches: "Photosynthesis"; 500 million years ago sunlight was able to create and propagate life on earth through this process. "Light energy" transfers into "Chemical energy"; these were very beginnings of life as we know it. Then single cell organisms forms eventually turned into fish, reptiles, birds, and last but not least: "mammals" of whom we are descendants of. The real question in the evolution of race/species should be: if "Homosapiens" are so smart that we can comprehend the universe, why is it that some species are still living in the Jungles of Africa? In actuality, we don't need to understand how the universe works, and if it weren't for Newton and Einstein, we'd know less about it than what we actually do, which is to say not much! But it's hard to see why even in our own species, some men have evolved technologically more advance than others.
Scientists still to this day aren't 100% sure what caused the "homosapiens" brain to enlarge? Also, for years there was the "baddest boy in the jungle" theory. Now they say otherwise. That although looks are important in attracting ones mate, Personality and other traits do not fall short in the conquest. This study is known as "Physiological evolution."
So "evolution of race" is different than what we thought it was at one point. What causes a "Octopus" for example to have remained the same for 100 million years. What causes the "Great White Shark" to have remain the same for more even? These questions are just recently being answered but not without a certain amount of controversy. For evolution states that a "Carp" for example had no reason for wanting to change, but so called human beings did in order to survive.
The real question is: Why didn't the "carp" change but "human beings" did? Did the Carp know that it's species had nothing to worry about "remaining a Carp," and "Humans" knew that theirs would come to an end unless the whole "Natural selection process" bit took place? Many questions remain unanswered but one things for sure. No one was there to know 100%....