"Cro-Magnon" is a modern human, Homo sapiens sapiens.
"Cro-Magnon," while out of favor with anthropologists, is the name still used by laymen for the first population of modern humans to migrate into Europe. This is the Occitan name (a Romance language sort of halfway between French and Italian) of the site where their remains were first discovered, meaning simply "Big Cave."
H. sapiens speciated more-or-less 200KYA, but remained in Africa until around 60KYA, when a drought caused by an ice age encouraged a party of explorers to cross into Asia looking for better feeding prospects. They eventually found it in Australia. A second party made the same excursion 10,000 years later, but the weather had improved and they made a new home in southwestern Asia. These are the people whose descendants are the ancestors of all living humans except Africans and Native Australians.
That includes the exploring party that found its way into Europe around 35KYA and displaced the Neanderthals: the Cro-Magnon. Current research indicates that they didn't kill them off, merely out-competed them with physiology more suited to the warming climate. Modern Europeans have significant traces of Neanderthal DNA.
The Cro-Magnon were strictly a Paleolithic ("Early Stone Age") people: nomadic hunter-gatherers who never invented agriculture and therefore never established permanent villages with cultivated crops and herded animals.
The Cro-Magon, in turn, were displaced by the Indo-Europeans, a second migration from Asia around 3000BCE. The Indo-Europeans had already developed agriculture or learned it from their neighbors, so with this technological advantage they quickly took over the entire European continent. The only community in Europe that is clearly not Indo-European and whose ancestry can't be determined (we know where the Finns, Huns, Magyars, Jews and Turks came from) are the Basque people of the Pyrenees. They may be the last Cro-Magnons. I don't think we've found any viable Cro-Magnon DNA to compare it to.
Well, it's not completely known the timing of evolution of things like skin color . . . .
Nonetheless we have plenty of evidence of it changing fairly rapidly in response to change in sunlight exposure. The dark-skinned people of southwestern India and the light-skinned people of Lithuania are all descended from the Eastern branch of the Indo-European people, and are separated only by three or four thousand years of migration in opposite directions. So when we're talking about
H. sapiens wandering around Eurasia for fifty thousand years (and the Americas for ten or fifteen thousand), skin color begins to seem like a rather ephemeral trait.
. . . . or even more fundamental aspects such as the split from chimpanzees. . . .
Just in the past few years we've discovered the remains of
Ardipithecus, a true "missing link" who was clearly bipedal yet retained an opposable big toe for easily scampering back up into the trees to escape predators. Ardi, the ancestor of all hominine genera and species, is seven million years old. She also resolved the burning question of where our first human-like ancestors lived: Ardi lived in the forest, not on the savannah.
. . . . perhaps they wouldn't be as "racist".
Most primates practice incest as a matter of course, to the extent that two gorilla skulls collected 500 miles apart look like they're from different species. But humans have a very strong instinctive attraction to people who look much different from themselves. Racism is a cultural overlay; we're not wired that way.
Anthropologists in earlier eras, who were able to study pre-modern tribes who had not yet been "contaminated" by commercial, religious and military contact with Europeans, found that they typically organized summer festivals. When food was abundant so there was no need for animosity, many different tribes got together to trade recipes, hunting strategies, herbs, stories... and children! This constant mixing of the gene pool was surely a survival advantage.
How many of us who are reading this thread give a second glance to a person of the opposite sex who has a different skin color or some other clear identifier of being "foreign," when we might have absentmindedly just walked right past five gorgeous people of our own genotype?
Even in the Old South, where people of African ancestry were officially called "inferior," the planters were always sneaking out into the slave quarters at night, and children of mixed-ancestry were a "dirty little secret" that they quietly sent off to schools in Europe where they didn't draw so much attention. Read up on the
Westermarck Effect for an astounding study of just how averse our species is to inbreeding. It was discovered in certain types of Israeli kibbutzes where all the children are raised communally on weekdays and only see their parents on weekends. Even though they know that they're not related to each other, kibbutz-mates very seldom marry as adults. It's an instinct that kicks in.
But there is also the problem of culture, perhaps different tribes have/had different standards. It would be interesting to have contact with isolated African and American aboriginal tribes and try to find out how they see the phenotypes of European or fair-skinned Asians, and Africans for Americans and vice-versa.
Unfortunately we're a little late for that. There are very few people on earth today who have not seen lots of foreigners.
