tag:blogger.com,1999:blog-7315236707728759521.post8739339084896957803..comments2024-03-28T21:52:52.100-06:00Comments on Dispatches From Turtle Island: Some Important Open Issues In Human PrehistoryAndrew Oh-Willekehttp://www.blogger.com/profile/02537151821869153861noreply@blogger.comBlogger11125tag:blogger.com,1999:blog-7315236707728759521.post-70363293108165800202013-06-04T21:54:07.706-06:002013-06-04T21:54:07.706-06:00"it is very hard to argue I think with the ov..."it is very hard to argue I think with the overwhelming circumstantial evidence pointing to the arrival of modern humans as the proximate cause and tipping point of megafauna extinction". <br /><br />Exactly. It is possible to claim alternative causes for individual cases but considered as a whole the evidence is pretty compelling. <br /><br />"Fitting two non-Neanderthal, non-modern human archaic species into Eurasia (presumably pre-OOA), is not an easy task". <br /><br />I don't see a problem there. After all Denisovans and Neanderthals were very close neighbours, leaving a considerable amount of Eurasia for other species. <br /><br />"the only other real candidate I can come up with as the second archaic hominin species would be H. Ergaster (sometimes called African H. Erectus and believed to be ancestral to all known Eurasian hominin species)" <br /><br />My vote goes towards an East Asian separate species, perhaps descended from 'Pekin Man'. When the information on the EDAR370 variant came out the authors suggested one possibility was introgression from some unknown East Asian species as well as a possible mutation within Homo sapiens. I thought the former scenario quite likely. <br /><br />"If Denisovans are a late evolutionary phase of H. Erectus that first admixed with H. Heidelbergensis to the west of their range and then late admixed with Neanderthals who replaced them to the west of their range (at least amongst N. Asian Denisovans) (with H. Flores being a pygmy species of H. Erectus due to island dwarfism that probably lacked Neanderthal or H. Heidelbergensis admixture), then you start to have a pretty coherent story". <br /><br />Possible. But I think you are hugely influenced by your desire to fit the Australasian Denisova genetic trace with SE Asian Homo erectus. At this stage we have no evidence at all that SE Asian H. erectus had any significant genetic connection to Denisovans in the Altai. That is a huge distance and for most species with the apparent limited mobility of pre-modern humans would be sufficient to give rise to separate species. The distance involved certainly seems sufficient to have given rise to separate species within other genera. terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-87291093266149809032013-06-04T12:04:10.544-06:002013-06-04T12:04:10.544-06:00Whether the mechanism was directly due to overhunt...Whether the mechanism was directly due to overhunting of megafauna or was more subtle and indirect, it is very hard to argue I think with the overwhelming circumstantial evidence pointing to the arrival of modern humans as the proximate cause and tipping point of megafauna extinction. The fact that it occurs in both continents of the Americas, in Northern Asia, in Australia, and in New Zealand, all very close in time to the arrival of modern humans and that almost every single one of dozens of species of megafauna go extinct at this moment of first contact in each of these places, despite the timing of first contact being different in different places, argues very strongly for modern human arrival being the tipping point. And, the fact that megafauna faired better in Africa and South and Southeast Asia where contact with archaic hominins may have "inoculated" local megafauna by allowing them to co-evolve with hominins is a case of the exceptions proving the rule.<br /><br />Re the Denisovan admixture with yet another unknown archaic hominin species (i.e. not modern human and not Neanderthal), this really is exciting and mysterious. Fitting two non-Neanderthal, non-modern human archaic species into Eurasia (presumably pre-OOA), is not an easy task. I am inclined to think that one of Asian H. Erectus (probably Denisovan) and the only other real candidate I can come up with as the second archaic hominin species would be H. Ergaster (sometimes called African H. Erectus and believed to be ancestral to all known Eurasian hominin species), or Homo heidelbergensis aka Homo rhodesiensis which was antecedent to Neanderthals in essentially the same range and were probably antecedent to modern humans in Africa. There is no attested instance of H. Ergaster outside Africa, although arguably this is due to geography influenced taxonomy since not everyone agrees that H. Ergaster and H. Erectus are the same species.<br /><br />If Denisovans are a late evolutionary phase of H. Erectus that first admixed with H. Heidelbergensis to the west of their range and then late admixed with Neanderthals who replaced them to the west of their range (at least amongst N. Asian Denisovans) (with H. Flores being a pygmy species of H. Erectus due to island dwarfism that probably lacked Neanderthal or H. Heidelbergensis admixture), then you start to have a pretty coherent story.<br /><br />The plot would really thicken if the trace unidentifical archaic admixture in the Denisovans and the trace archaic admixture in either certain Khoisan or certain pygmies in Africa were a match - pointing strongly to the possibility that there were relict populations of H. Heidelbergensis both in and outside Africa through the Upper Paleolithic (with the other of the two separate unaccounted for archaic admixture in African populations possibly being a trace of H. Ergaster (I'd guess Ergaster for the Khoisan and Heidelbergensis for the Pygmies in light of the probably archaic admixed Y-DNA haplogroup found in West Africa near Pygmy territory and based on the need for Heidelbergensis to be closer to Eurasia than Ergaster - also we know that Ergaster's range extended to Southern Africa based on fossil evidence but have no evidence of Ergaster in jungle settings - perhaps due to preservation conditions, but perhaps because they never lived there). If H. Heidelbergensis evolved north of the Congo and never migrated to Southern Africa, then H. Ergaster would be the most evolved archaic hominin species in Southern African upon first contact with modern humans and might have survived for some time as a relict population in marginal environments that the Khoisan would eventually themselves being pushed into.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-31483241114372149922013-05-21T21:05:20.212-06:002013-05-21T21:05:20.212-06:00Sorry. I left this bit out:
"But it's ...Sorry. I left this bit out: <br /><br />"But it's hard to argue from those isolated cases that humans were responsible for wiping out entire species. Far from rampaging across the continent, killing every large mammal in sight, it seems ancient hunters may have had a more subtle, but no less terminal impact. Over thousands of years, the level of hunting was just enough to be unsustainable for these huge, slow-breeding behemoths of the ice age". terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-27219727532700295242013-05-21T21:03:53.135-06:002013-05-21T21:03:53.135-06:00"6. What archaic hominin species is Denisovan..."6. What archaic hominin species is Denisovan DNA associated with?" <br /><br />I don't know if you've noticed John Hawks' latest post, but just in case you haven't here it is: <br /><br />http://johnhawks.net/weblog/reviews/denisova/biology-of-genomes-pennisi-update-2013.html<br /><br />Some interesting aspects: <br /><br />"And the comparison revealed another surprise: Four percent of the Denisovan genome comes from yet another, more ancient, human—'something unknown,' Pääbo reported". <br /><br />So we have yet another ancient Homo species that could interbreed at least with another species that could interbreed with 'modern' humans. In fact the whole thing gets even more complicated: <br /><br />"With all the interbreeding, 'it's more a network than a tree,' points out Carles Lalueza-Fox" <br /><br />On another matter, that Maju gets extremely worked up about, this article on mammoth extinction was published in a local paper recently: <br /><br />http://www.nzherald.co.nz/world/news/article.cfm?c_id=2&objectid=10884722<br /><br />Quote: <br /><br />"Among late-surviving mastodons he has studied, Dan is finding examples of females losing calves (where one pregnancy is immediately followed by another, rather than by two years of lactation) and of males going into musth early (just as young bull elephants do in Africa, when mature males are poached out). Dan had also found examples of mammoths dying in the autumn, a time of year when they should have been in peak condition. Autumn deaths argued for an extrinsic cause of death. For Dan, all this could be pinned on one such cause: overhunting by humans". <br /><br />Note: 'just one cause'. I dare you to bring this to Maju's attention! terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-56491265722848410172013-05-16T17:09:06.405-06:002013-05-16T17:09:06.405-06:00FWIW, I think that LT probably has Mesopotamian or...FWIW, I think that LT probably has Mesopotamian origins with L breaking off from T with the proto-Harappans and the T staying in Mesopotamia and then expanding from there with early Neolithic expansion.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-64729513572887424802013-05-04T18:25:48.864-06:002013-05-04T18:25:48.864-06:00Very interesting comments about Y-DNA T. Perhaps ...Very interesting comments about Y-DNA T. Perhaps it did coalesce further west along the route to SE Asia than I have so far considered likely. That would place JT as forming around the Anatolian plateau, LT somewhere in southern Iran and MNOPS in SE Asia. But that leaves South Asia suspiciously blank, only F haplogroups. terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-8685709233642306532013-05-03T15:50:02.938-06:002013-05-03T15:50:02.938-06:00Re Y-DNA T see the maps here: http://dispatchesfro...Re Y-DNA T see the maps here: http://dispatchesfromturtleisland.blogspot.com/2011/10/evidence-regarding-dravidian-linguistic.htmlandrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-45983253974406517192013-05-03T01:53:17.617-06:002013-05-03T01:53:17.617-06:00"the haplogroup evidence of Papuans and Abori..."the haplogroup evidence of Papuans and Aboriginal Australians just screams out for tiny population sizes". <br /><br />That is not entirely correct. Australia has two basal M haplogroups (M14, M15) as well as the derived M42a, four basal N haplogroups (N13, N14, S and O) as well as one basal R haplogroup (P) and the derived R haplogroup R12. Although New Guinea has no basal N haplogroups it has three entirely different basal M haplogroups (M27, M28 and M29'Q) as well as R14 (shared with the Lesser Sunda Islands) and several P-derived haplogroups (presumably from Australia). That doesn't exactly 'scream' tiny population sizes, especailly not for Australia. <br /><br />"Y-DNA haplogroup T - it is Eastern South Asia, not Western" <br /><br />Are you sure of that? I used to be convinced it was so but now I'm not so sure. The reason I originally thought it was so is because at that time it was still part of what is now called MNOPS, which is definitely from east of South Asia. But now it has been shown to be separate I accept it formed along the route from Africa to SE Asia. <br /><br />"and doesn't belong in the high frequency geographically tiny area where it is found unless it is a recent arrival". <br /><br />I think it is certainly a recent arrival, in the sense of around 10-12,000 years ago, through much of the western regions where it is found today. <br /><br />"it doesn't appear that there was any admixture in mainland Asia where most H. Erectus must have lived. They went completely extinct in most of their range". <br /><br />I actually believe our evolution has been far more complicated than the simple story usually presented. terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-21821646271555487552013-05-01T17:09:32.073-06:002013-05-01T17:09:32.073-06:00The methods in the nature.com article are very fli...The methods in the nature.com article are very flimsy and make important unreasonable assumptions (e.g. population bust from LGM, steady rate of growth otherwise rather than logistic curve, assumption of linear relationship between tool production and population), and the haplogroup evidence of Papuans and Aboriginal Australians just screams out for tiny population sizes. A hundred is probably close to the mark (and the notion that you can fit an exponential equation over 1,550 generations with the requisite level of precision to get a factor of ten right when the number of generations itself is probably variable to +/- 100 generations or so, is absurd.<br /><br />Re: Y-DNA haplogroup T - it is Eastern South Asia, not Western, which is why it is so odd. You see it in Mesopotamia, Ethiopia, early Neolithic Europe, Semitic populations in Africa, and eastern South Asia - hopping over an L region. It is probably Mesopotamian in origin and doesn't belong in the high frequency geographically tiny area where it is found unless it is a recent arrival.<br /><br />I am defining extinct to mean "cease to exist as a separate species if the resulting species is predominantly the other part of the hybrid." Also, it doesn't appear that there was any admixture in mainland Asia where most H. Erectus must have lived. They went completely extinct in most of their range.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-15577111599157473352013-05-01T17:06:59.642-06:002013-05-01T17:06:59.642-06:00At the risk of annoying you as much as I annoyed M...At the risk of annoying you as much as I annoyed Maju I'd like to draw your attention to this little gem: <br /><br />http://cuevadelapileta.blogspot.co.nz/2013/05/clues-to-southeast-asian-civilisation.html<br /><br />Maju will hate it because: <br /><br />"The discovery tells us that the Con Co Ngua people are likely descendants of the original colonisers of Southeast Asia and Australia. In fact, putting flesh back on their bones would reveal people that looked a lot like modern day indigenous Australians and Melanesians". <br /><br />What maju got most annoyed with me about was my insistence that the 'Mongoloid' phenotype of modern SE Asians is the product of later movement into the region. He doggedly maintained the Mongoloid phenotype was indigenous to the region. But here we have research showing that the 'Melanesian' phenotype survived in North Vietnam until at least 'sometime between 5,000 and 6,000 years ago'. terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-74483968249642656292013-05-01T16:53:31.484-06:002013-05-01T16:53:31.484-06:00"Tenatively, I favor an arrival of R1b predom..."Tenatively, I favor an arrival of R1b predominantly with the Bell Beaker people" <br /><br />I've come to that conclusion too, after long assuming R was Paleolithic. I see Maju is claiming a pre-Neolithic presence of R1b1a2a1a1b-S116 in Iberia but note its long series of numbers and letters and so its very downstream nature. And its spread coincides reasonably well with megalithic distribution. The other widespread European R is R1b1a2a1a1a-U106 which to me looks perhaps part of Indo-European's spread into Europe. Both are relatively recent into at least Western Europe I suspect. <br /><br />"mutation rate based dates are too uncertain to resolve the issue" <br /><br />I agree. But Dienekes has listed R1b1a2a1a1a5-S264 at 6500-7000 years. Fits. <br /><br />"there is increasingly little reason to doubt that linguistically Indo-European didn't arrive in Western Europe until at least the Urnfield culture, and that prior to that point almost the entire maximal range of Bell Beaker influence had at some point been linguistically Vasconic". <br /><br />Agreed. I suspect that Indo-European was first spread by R1a haplogroups, but the language spread far beyond the haplogroup expansion. <br /><br />"The possibility that outlier sites could represent archaic hominin populations that made the trip before modern humans but left a very modest footprint because their lithic technology was less advanced and they were less ecology distrupting top predators is particularly intriguing if the evidence becomes strong enough to force us to fit the theory to it". <br /><br />Those archaic Americans may have comprised such a small gene pool that inbreeding prevented expansion, or perhaps even their eventual extinction. It was only with the arrival of greater numbers that the population was able to expand considerably and leave its mark on the environment. There is evidence for something similar having happened in New Zealand with evidence of man-induced fires perhaps a thousand years before the definite evidence of human arrival. By the way, have you seen the paper regarding colonising numbers in Australia? Here it is: <br /><br />http://www.nature.com/news/first-australians-may-have-been-migrants-rather-than-drifters-1.12865<br /><br />One thousand people. Not accidental arrivals. <br /><br />"There is no solid indication of Neanderthals beyond South Asia" <br /><br />As far as I'm aware there is actually no evidence for Neanderthals anywhere within South Asia apart from some disputed presence in the far northwest. <br /><br />"How did Y-DNA haplogroup T end up in the western part of South Asia?" <br /><br />I strongly suspect it originated there. It is 'brother' to L which is definitely a South Asian haplogroup. <br /><br />"How did Homo Erectus go extinct?" <br /><br />I think that technically it didn't become extinct. Collectively we probably have many genes picked up by 'modern' humans as they passed by and mixed with Homo erectus populations. terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.com