Posted on 02/26/2006 3:25:01 AM PST by Pharmboy
Maybe they just didn't have time to get to know each other.
The question of what Neanderthals and Homo sapiens might have done on cold nights in their caves, if they happened to get together and the fire burned down to embers, has intrigued scientists since the 19th century, when the existence of Neanderthals was discovered.
A correction in the way prehistoric time is measured using radiocarbon dating, described last week in the journal Nature, doesn't answer the enduring question, but it might at least help explain why no DNA evidence of interbreeding has been found: the two species spent less time together than was previously believed.
The old radiocarbon calculation is now known to be off by as much as several thousand years, the new research shows. That means that modern Homo sapiens barged into Europe 46,000 years ago, 3,000 years earlier than once estimated. But the radiocarbon dating under the new calculation also shows that their takeover of the continent was more rapid, their coexistence with the native Neanderthals much briefer.
snip...
Was that advantage cognitive, technological or demographic? Their personal ornaments and cave art, now seen to have emerged much earlier, are strong evidence for an emergence of complex symbolic behavior among the modern newcomers, a marked advance in their intelligence.
That doesn't mean they didn't interbreed with the Neanderthals.
snip...
"Since these two species may have been able to interbreed, as many closely related mammal species can," Dr. Harvati said, "a restricted coexistence interval may be easier to reconcile with the observed lack of Neanderthal genetic contribution to the modern human gene pool and with the paucity of convincing fossil evidence for hybridization."
The caves, it would seem, still hold their secrets.
(Excerpt) Read more at nytimes.com ...
No, not really. It's intriguing to think about though. As I said in another thread just yesterday, it's perfectly OK by me if people want to fantasize hot sweaty cavesex between Neanderthals & Cro-Magnons, I just think it flies in the face of what evidence we have (at least as any remotely widespread phenomenon). Now, maybe the evidence will change to indicate differently, but until that happens one might only offer contrarian conjecture while the evidence points elsewhere.
What is more interesting is how did they survive in Ice Age Europe through two different 100,000 year Ice Ages. It couldn't have been much fun.
I agree that's a very intriguing question!
Many traits that distinguish Neanderthals are present in modern humans also. So, I wonder how the claim that no interbreeding occurred can be made.
It is my understanding both species lived in close proximity simulataneously for 11,000 years in caves discovered in Israel.
Well, fwiw, in my personal opinion this bit is actually on the right track, which is somewhat astounding!
As for the rest ... meh... whatever.
The DNA evidence does NOT support interbreeding. While it is not definitive, it is pretty strong.
I believe that based on carbon dating, those may have to be revised.
I suppose, then, that the natives at the source of the Nile were a subspecies (or a separate one altogether) of those that lived at the mouth of the Nile 3000 years ago?
Do you believe it possible that tools/artifacts/art/food/customs/etc. are subjected to modern ethnocentric prejudices?
Modern Human Origins and Neanderthal Extinctions in the Levant
Evolutionary Changes in Modern Human Behavior: Current fossil evidence shows that only early modern humans were present in the Levant between 130,000-80,000 BP, and re-appear again after the Middle-Upper Paleolithic Transition, around 47,000-40,000 BP. Only Neanderthal fossils appear in the intervening period, 75,000-47,000 BP. Bar-Yosef (1988) has suggested that the rapid onset of glacial conditions around 75,000 BP caused Neanderthal populations to migrate south from montane western Asia into the Levant corridor.Far from displaying a “transitional” population, the early modern human fossils from the Levant seen to possess Neanderthal affinities (Skhul and Qafzeh) date to before the first occurrence of Neanderthal fossils in this region while human fossils from adjacent parts of Northeast Africa, such as Tamrasa Hill I, that are contemporaneous with Levantine Neanderthals preserve no trace of Neanderthal morphology (Vermeersch et al. 1998). Then, around 45,000-35,000 BP, Neanderthal fossils cease to occur in the Levant at exactly the point when Upper Paleolithic industries first appear in Israeli and Lebanese cave sites (Bar-Yosef 1996). By 30,000 BP, Neanderthals continued to practice Middle Paleolithic adaptations in a few isolated refuges, such as southern Spain and western Asia. Shortly thereafter, Neanderthals became extinct, replaced by Upper Paleolithic modern humans. [bold print added]
The heck, can't you read? That link clearly states that the evidence shows there has been no mixing of Neanderthal mitochondrial DNA into the human population. Yes, they say they are difficulties, but they clearly feel these have been surmounted.
What does Neanderthal DNA look like: Like human DNA or chimp DNA, but with significant differences.
How was it collected: Extracted from Neanderthal bones and amplified by PCR (hint--perhaps if you don't know what PCR is you are not qualified to make a judgement on the validity of this study).
How do we know the sample obtained is Neanderthal DNA: Because it came from Neanderthal bones and shares many similarities with human and chimp DNA.
Where was the DNA obtained: A variety of European sites.
The mitochondrial DNA argument can indeed stand rudimentary (perhaps "elementary" is a better descriptor) questions. Just because you don't understand it does not mean it is wrong.
If you really want all of your methodological questions answered in depth, I suggest you look up the original article and any supporting information provided for it.
Okay, thanks! I guess I'm justwondering what it is about the differences in bone structure that would lead scientists to suspect that a union between the two groups would be sterile.
However, one thing that is now much, much clearer that it was just a decade ago is that Neanderthal and Cro-Magnon behavior was far more different than had been thought the case. The Neanderthal had inferior tools, inferior weapons, inferior artistry, etc.
So, if it were a full sentence, it would be: The Neanderthal had inferior tools, inferior weapons, inferior artistry, etc. than what had been thought the case just a decade ago.
I don't see what the problem is with that observation. It's true.
As for ethnocentric prejudice (or even speciescentric prejudice as the case may be) I suppose there could be some of that, but when the Cro-Magnon had cave painting and clay sculpture whereas the Neanderthals are not known to have painted or sculpted anything, that is a rather objective measurement of inferior artistry.
That I don't know. To my knowledge, the biggest indication of sterility between the two groups is the apparent absence of Neanderthal mtDNA sequences in modern European populations.
PS. And you'd think I'd correct my typo in that excerpt the second time around! :)
The Lagar Velho child has subsequently proven to be a modern human child not a hybrid.
You might be right, but you are still left with little but idle conjecture to support the notion that Neanderthals were assimilated by Cro-Magnon.
And as for myself, I'll essentially repost the comment I made on this topic yesterday: Any interbreeding was probably minimal at best. So, I am not saying that it never happened at all, just that it almost certainly didn't happen to any degree of consequence.
He might sic the Memsaab on ya...
What does the level of technological development or cultural sophistication have to do with determining species? We have people on this planet living in the stone age while others can split an atom. Yet, they can interbreed producing viable offspring which means they are from the same species.
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