Darwin's Beagle trip was in the early 1830's. He hesitated and procrastinated publishing his manuscript until Robert Boyle(?) and other friends pushed him to publish to avoid Wallace getting the credit who has just returned from his round the world tour. Both Darwin and Wallace presented to the Royal Society of London on the same night. Darwin presented first and is given the credit for evolutionary theory. He deserved it has he had been compiling and working on it considerably longer than Wallace.

@t1nick: I said nothing to the contrary ab't that.

"Race" has a very specific meaning in biology. An example of biological race is the Tanzania chimpanzee and the Gambian chimpanzee. At one time both groups were the same population. But at some point in the past one group broke off from the original group and migrated. Over time due to geographic isolation, both groups continued to evolve separately, adding independent changes to their individual gene pools, such that today, both groups genetically appear almost identical but with minor genetic changes that distinguish each population from one another. Enough different that they would not naturally mate in the wild under normal conditions.

In humans there is no genetic marker for individual races. The distinct features that we see among human populations are more a matter of sexual selection and geographic adaptation. If your population lives closer to the equator where UV Ray's are more pervasive you adapt by producing more melanin giving a darker complexion. So naturally, the more melanin you produce to protect you from the sun, the more "evolutionarily "fit" you are. So sexual selection contends that you look for a mate which with better"fitness", thus darker in skin color. This holds true for other attributes that individual populations deemed sexually attractive.

The reverse is true for the very northern and southern latitudes. Less sunlight, so in order to produce more vitamin D, your need less melanin blocking the UV Ray's. So you look for a mate that is very fair.

Now humans are not bounded by geographic isolation.
Because humans are so mobile and have traveled so extensively from early on in our history, we have intermarried and interbred around the globe. We possess genes from every human group, no matter how isolated in our gene pool. Even if a trait isnt expressed in our phenotype, we still carry a remnants in our gene pool. That is why we do not have a genetic distinction in our gene pools that would distinguish groups as "racially" different, because we are not.