Compared to other animals, humans have very little genetic diversity, e.g.
http://humanorigins.si.edu/evidence/genetics/skin-color/modern-human-diversity-genetics
People today look remarkably diverse on the outside. But how much of this diversity is genetically encoded? How deep are these differences between human groups? First, compared with many other mammalian species, humans are genetically far less diverse – a counterintuitive finding, given our large population and worldwide distribution. For example, the subspecies of the chimpanzee that lives just in central Africa, Pan troglodytes troglodytes, has higher levels of diversity than do humans globally, and the genetic differentiation between the western (P. t. verus) and central (P. t. troglodytes) subspecies of chimpanzees is much greater than that between human populations.
I've read at least one claim that there is less diversity in the entire human race than in a typical group of 40 African monkeys of the same species, although that sort of quote is the kind of thing which you'd never find when looking for it...
This lack of diversity is generally attributed to a population bottleneck of sorts which most scholars place around 45,000 years ago, some claiming there may have been as few as 50 modern humans on the planet at that time. Nonetheless, those claims generally assume some sort of a transition from "early modern humans(TM)" (meaning gracile hominids) to Cro Magnon humans at that time.
Is that really believable, or did Cro Magnon people simply arrive here at that time and begin replacing ALL hominids, gracile and otherwise? One thing scholars all agree on is that whatever caused Cro Magnon people to appear on this planet when they did was not gradual. Danny Vendramini ("Them and Us") notes:
“The speed of the Upper Palaeolithic revolution in the Levant was also breathtaking. Anthropologists Ofer Bar-Yosef and Bernard Vandermeersch:“Between 40,000 and 45,000 years ago the material culture of western Eurasia changed more than it had during the previous million years. This efflorescence of technological and artistic creativity signifies the emergence of the first culture that observers today would recognise as distinctly human, marked as it was by unceasing invention and variety. During that brief period of 5,000 or so years, the stone tool kit, unchanged in its essential form for ages, suddenly began to differentiate wildly from century to century and from region to region. Why it happened and why it happened when it did constitute two of the greatest outstanding problems in paleoanthropology.”
Likewise Dwardu Cardona ("Flare Star"):
Where and how the Cro-Magnons first arose remains unknown. Their appearance, however, coincided with the most bitter phase of the ice age. There is, however, no doubt that they were more advanced, more sophisticated, than the Neanderthals with whom they shared the land. Living in larger and more organized groups than had earlier humans, Cro Magnon peoples spread out until they populated most of the world. Their tools, made of bone, stone, and even wood, were carved into harpoons, awls, and fish hooks. They were presumably able hunters although, as with the Neanderthals, they would also have foraged to gather edible plants, roots, and wild vegetables. The only problem here is that,as far as can be told, the Cro Magnons seem to have arrived on the scene without leaving a single trace of their evolutionary ancestors.'When the first Cro Magnons arrived in Europe some 40,000 years ago', Ian Tattersall observed, 'they evidently brought with them more or less the entire panoply of behaviors that distinguishes modern humans from every other species that has ever existed.'"
All of that is consistent with thinking that Cro Magnon man CAME to this planet 45,000 years ago or however long ago that was, and it is not consistent with thinking that man evolved from hominids.
In fact the huge eyes of the oldest groups of creatures on this planet, including dinosaurs and hominids, indicate that this planet was originally an exceedingly dark sort of place. Humans, with the smallest eyes relative to body size of advanced creatures could not have come from such a place.
http://news.medill.northwestern.edu/chicago/news.aspx?id=184900 
http://www.independent.co.uk/news/science/neanderthals-large-eyes-led-to-their-downfall-says-study-8532539.html 
Those were the kinds of eyes you needed when "darkness was upon the face of the deep"...
Cro Magnons and their descendants are one of what I'd view as the two basic human groups, the other being the familliar antediluvian people of the Bible. The difference has nothing to do with race or color, either group is capable of producing any color or feature you'd ever see in humans. Japanese Ainu, who most view as white, and Australian Aborigines who most view as black, are both Cro Magnon descendants.
The two groups are genetically identical or close enough to that to neglect the differences. They amount to separate saltations from the same source, separated by a large enough space of time that the two cultures and technologies were totally different.
If you wanted to believe that Adam and Eve were descended from Cro Magnons, there is a list of things which the Bible and Jewish literature would have to know about, and which they don't, which would include (at minimum):
- Stone tools. Adam and Eve and their descendants were metal-tech people from day one (e.g., Genesis 4:22). By contrast, human groups descended from Cro-Magnons went on using stone tools until forced out of it by neighbors descended from Bible Antediluvians if they ever stopped at all. Aztecs were using stone knives and weapons when the Spanish arrived even though they used metals for ornaments and purposes other than tools.
- The atlatl, the signature weapon of Cro Magnon people. Biblical accounts know nothing of this weapon; the weapons of the Bible were the sword, the spear, the sling, and the bow. By contrast, the Aztecs, a people descended from Cro-Magnons1, were using atlatls against the Spanish while native Australians continue to use it to hunt kangaroos today.
- Neanderthals and/or other hominids. The Bible knows nothing of hominids. By contrast, the Basque "Basajuan" appears to be a reflection of the Neanderthal and the Australian "Yowie" appears to be some sort of hominid, which native Australians remember.
- An upper Paleolithic world war in which all hominids were exterminated from the planet, or at least from the parts of the planet that humans inhabit in any numbers.
- A primordial era generically referred to [by scholars who study myths and oral traditions] as the "Purple Dawn"; that is, a protracted age devoid of the daylight that we experience today.
Cro Magnon people experienced all of those things and their oral traditions more often than not show traces of them. The basic idea is that the two groups are from the same place, but their arrivals here were separated by thousands of years so that the culture and technology had totally changed by the time Adam and Eve and anybody else who may have come with them arrived.
There is no good word for the people prior to Adam and Eve. The term "Cro Magnon" has been declared a tabu word by scientists because nobody could figure out who all to include; the term "Pre-Adamite" is politically incorrect from being used in racist tracts 90 years ago; and the term "Early Modern Human" includes Skhul/Qafzeh hominids which, in real life, were still hominids and not humans.
Puple Dawn:
http://saturndeathcult.com/the-sturn-death-cult-part-1/a-timeless-age-in-a-purple-haze/
Human/Hominid Non-Relation:
http://www.youtube.com/watch?v=pe6DN1OoxjE
http://www.youtube.com/watch?v=MhFXQHRAzg8
Ganymede hypothesis:
http://www.youtube.com/watch?v=-p10PiJPEq4
http://cosmosincollision.com
All of this stuff is substantially at variance from 99% of what is taught in schools and also from what you'll find on normal Internet resources. Nonetheless, the stuff they teach plainly doesn't work. For a hominid to have ever evolved into a human, that hominid would need to have:
- Lost his fur while ice-ages were going on.
- Lost almost all of his sense of smell while trying to survive as a land prey animal [fatal]
- Lost almost all of his night vision in an age when night was the only time of day that there was.
If that doesn't sound like a formula for success, then neither should the idea of God creating a creature for a world for which the creature was hideously maladapted. There is nothing in the Bible about God being STUPID.....
Cosmos in Collision does in fact describe the reasons for our planet having been super-dark in ancient times. Kindle is everybody's friend...
http://www.amazon.com/Cosmos-in-Collision-ebook/dp/B00C4MF8UE/ref=sr_1_1?ie=UTF8&qid=1364793440&sr=8-1&keywords=cosmos+in+collision