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 ...
At some point during the evolutionary chain (according to the theory) life became more complex.
Now surely, homo sapiens and the Neanderthal have much in common. Much more in common, than say a man and horse. In fact, the scientific communities assumptions on the Neanderthal have changed greatly over the years. According to the evolutionary theory itself, homo sapiens and Neanderthal are related, regardless of what DNA evidence is presented to the contrary. This is obvious to any observer - the two have incredibly similar features.
Modified reconstruction of Gibraltar Neanderthal child
So why does the scientific community invest so much time and energy to try to divorce the two?
Homme de Néanderthal
Perhaps this chart will help.
The two are certainly related, and share a common ancestor. I think the issue being discussed here is the amount (if any) of intermixing between modern humans and Neanderthal.
Many think that after the separation there was essentially no intermixing and that Neanderthan eventually died out.
Source: http://wwwrses.anu.edu.au/environment/eePages/eeDating/HumanEvol_info.html
Thanks.
ROFLOL
Considering that guys have been known to screw goats, chickens, and whatever else didn't run away fast enough, it's pretty certain that there would be interbreeding attempts
Except of course that a Neanderthal weighed about 140 lbs more than a chicken, and goats don't carry spears.
Non-Btitish scientists were rejecting Piltdown as early as 1912 (even British publication didn't think it was a "good" find, then.) The parts didn't fit together. Even the most pro-Piltdown advocates only claimed a small leaf node on the Tree of Humanity.
If you take any small subset of human population, you will find distinctive aspects of the DNA of that subset. That is a direct consequence of the fact that sequence space is astronomically larger than whole populations, over the whole course of history. Which is the same fact used to recognize individuals by their DNA.
If you then ask, is that exact same subset of distinctive features found in some other separate population, the answer is overwhelmingly likely to be "no". But not because the other, separate population is a homogeneous pool in all respects, distinct from a likewise homogeneous pool that you choose as your starting point, and noticed the distinctive features of. Instead, any sizeable subset of the broader pop you compare it to, will also have distinctive features - just not *those* distinctive features.
Species are not points in sequence space but clouds. They agree on gobs and disagree on tiny subsets. N. and H.S. were supposedly unified at 500ky based on the degree of simularity noticed in their sequences. Which is itself a very rough analysis that assumes more pointlikeness (common descent from some X? But X is a cloud, not a single sequence) in the past than there was. What it really tells us is that people on different continents for 100ky periods had limited gene flow. Duh.
There is no reason to believe the markers used to tell N. from H. have any selective effect whatever, or matter for anything. They are fingerprint whorls, effectively. All they tell us is subpop A was not subpop B, which we knew by the operation "subset", and ordinary statistics.
The actual argument used in the paper linked, however, is transparently absurd. It claims any diffusion event will leave the diffusee vastly overprevalent in the subsequence pop. Without anything motivating the implied assymmetry.
It is clear to me what they did wrong. They talk about "logistic population" effects as an amplifier, but logistic under the assumption of a higher carry cap locally, is exponential in all but name. They assume that the pop of the crossover is exponentially expanding. And then they have only front crossover, no actual movement. Which damps any long range gene flow and only allows the supposedly so much more rapidly expanding bit to spread.
Such one sided exponentials litter models with specious results. If this happened we'd see it all the time in all other similar cases, but we don't. Assimilated subpops are not assured 95% genetic representation in larger pops assimiliating them. Duh. Instead, larger a few generations later, plus drift, form a strong attractive force for conservation of the most common alleles.
Until I see better evidence, I remain convinced that N. are completely made up, simple a trivially different subgroup of humans with modestly different hat sizes, being chased around by molehill mountaineers.
I think it's a safe bet that a lot of early couplings weren't voluntary and that women were the spoils of battle. That Neanderthal with the spear probably ended up carrying off the CroMagnon woman a good deal of the time. I'm also guessing that when given the choice between death or rape that most women of either group chose the latter.
Real timeline is too short. According to this website:
http://wwwrses.anu.edu.au/environment/eePages/eeDating/HumanEvol_info.html
H. sap and N. nea co-existed 100,000 years ago in Israel with a common stone industry. That would have been highly unlikely without interbreeding at that time, when the two groups were probably less differentiated.
Generally differention of a species into a new environment encourages significant diversity, later pruned as the niches fill up. The 20,000 years from then til now could very likely represent a significant selection effect, thus makng us more different from H. nea now, than our ancestors were then.
If the Neanderthal carried off a Cro-Magnon woman it would make no difference to the Cro-Magnon gene pool (or the modern human gene pool) because any child that the Cro-Magnon woman had would then be in the Neanderthal community and 100% of Neanderthal communities went extinct along with any intermixed genes that were over in them.
And, I will make this point yet again. Humans are extraordinary in their willingness to have sex with non-humans, and even amongst humans it is an extraordinary willingness. There is not the slightest evidence that a Neanderthal would even imagine having sex with a human. There is this inescapable tendency, I think, because of the great morphological similarity, to 'anthropomorphize' Neanderthals. Perhaps it sounds odd that I even object to this, but the animal kingdom is replete with very similar animals that have very different behaviors.
Let me give you an example: Dolphins. Bottlenose dolphins happen to be one of the extraordinarily rare species, such as humans, that will have sex with other species (a dolphin will have sex with a human, for instance). No other cetacean will.
Species after species after species will not have sex with closely related species even in cases where they would produce progeny - a moose and a cow for instance. In most cases, even closely related species such as cows and yaks will produce hybrid progeny that are only viable for about two generations before fertility attenuates below propagation.
This assumption that Neanderthals were nothing but humans with a brow ridge is utterly and totally absurd IMHO. There is simply no basis whatsoever for the idea that a Neanderthal would consider mating with a human; could even speak any intelligible language, much less the Cro-Magnon language; could produce viable hybrids, and hybrids that maintained fertility over multiple generations; or would find anything remotely attractive about a Cro-Magnon.
And then you get these tendentious "reproductions" which are nothing but more conjecture. So you have that red-haired Gibraltar girl above, quite obviously intentionally made to look as human as possible, with her sloping forehead concealed by a fictitious shock of hair (their hair was probably limp and greasy), with no discernable brow ridge to speak of, with no characteristic Neanderthal nose to speak of, and with nice pretty eyes and freckles to boot.
And we don't know if that even remotely resembles an actual Neanderthal. It almost certainly does not.
I could go on and on, but I am content with the mtDNA evidence because that's the best evidence we have to date. And not just that, but a glaring big huge elephant in the room: No mixed communities in the archaeological record, and a swift vanishing of Neanderthal communities almost exactly whenever the Paleolithic humans came along into an area.
I've read this line of BS before. Don't buy it for a second. It's some Asperger-syndrome geek trying to glorify his condition. (No need to; Asperger's Syndrome is strange enough without trying to bring neandertals into it.)
Hmm.. "anthropomorphize" was a bad choice of words; "humanize" works better I think for what I'm trying to convey.
Many think that after the separation there was essentially no intermixing and that Neanderthan eventually died out. >>
OTOH, maybe Adam and Eve's children married the Neandertals instead of each other....
And, opps! I meant a moose and a deer.
This article of course raises the other question, was a hard Neandertal good to find? >:0>
And one last clarification on my last post:
There's an implicit assumption in my wording that Cro-Magnons and Neanderthals were different species. In any case, the basic points I'm making apply just as well if they were sub-species (500,000+ years genetically removed from one another).
But FWIW my very strong personal view is that if Neanderthals were just today being discovered for the first time they would clearly be labeled a separate species. It is the fact that they were discovered decades ago, and that all this mythology grew up around them including the utterly false notion that the Cro-Magnon descended from Neanderthals, that keeps this debate going. IMHO.
And then of course you also have the fringe motivations: racists who want a separate evolutionary lineage for each race and creationists who want to abolish any evidence of hominid speciation. (And by no stretch am I assigning these motivations to even a majority of those who argue in favor of Neanderthal/Cro-Magnon admixture. But they are a motivation for some. I did say "fringe"..)
Your point about the differences in sexual appetites of Neanderthal vs Hss makes sense.
We also don't know, I am surmising, whether Neanderthal women were having a menstrual cycle in the manner of modern women.
This would make a large difference in the potential attractiveness, as well as viability of cross-breeding attempts.
Exactly! We have no idea whether Neanderthal and Cro-Magnon mating periods or fertility patterns matched up. A chimpanzee female for instance will generally not mate again for several years after giving birth. Was a Neanderthal more like that, or more like us - in terms of mating? We don't know.
Now of course in the grand evolutionary tree the Neanderthal was considerably closer to us, to say the least, than to a chimpanzee, but the point is that any number of additional factors could make a critical difference, such as menstrual cycles. So, in my view, the burden of proof in light of all the evidence is on those who would argue Neanderthal/Cro-Magnon admixture, and "because they were there" just doesn't cut it for me.
Another question: Did Neanderthal males have a 'pheromone trigger' as so many mammals do? A pheromone trigger that a human female would never trigger. Who knows? We don't. We never will. And the beat goes on!
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