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Martín Cagliari's blog, Mundo Neandertal, brings me to a quite interesting discovery: Acheulean findings of Iberia are much older than believed so far.
The sites of Solana de Zamborino (Granada) and Cueva Negra (Murcia) happen to be much older than believed so far. Until now these sites had been dated only based on their industry style, and therefore believed to have been from 400,000 BP on but the new sutdy by Gary R. Scott and Luis Gibert has found that, on geochronological grounds, the findings must be dated to c. 900,000 (Cueva Negra) and 780,000 BP (Zamborino).
This pushes the arrival of Acheulean to Europe back to the same date as the (believed) arrival of Pebble Culture and the oldest known H. erectus in the area (Homo georgicus, dated to c. 800,000 BP, considered intermediate between H. habilis and H. erectus, it seems).
Primitive navigation?
It also raises again the issue of whether H. erectus could have crossed the Gibraltar Strait from Africa to Europe. This was already believed based on the fact that both Pebble and Acheulean tools are found earlier in southern Iberia than further north.
But Gibraltar Strait was never totally closed in the Ice Age, so these Erectus people must have built some sort of boats or rafts to cross it. The other case suggesting some sort of boating skills in hominins is found at the other corner of Eurasia: in Flores. Homo floresiensis arrived to a remote island in Indonesia (also never directly linked to the contintent) somehow and surely it was not by means of mere swimming (how could whole bands do that, with children and everything?). These two seem to be the major documented feats of navigation by Homo species other than ours (for some reason, Neanderthals don't seem to have done anything of the like - the Bosphorus at best).
References:
· “The oldest hand-axes in Europe”. Gary R. Scott & Luis Gibert. NATURE| Vol 461|3 September 2009.
· EFE news article.
.
The sites of Solana de Zamborino (Granada) and Cueva Negra (Murcia) happen to be much older than believed so far. Until now these sites had been dated only based on their industry style, and therefore believed to have been from 400,000 BP on but the new sutdy by Gary R. Scott and Luis Gibert has found that, on geochronological grounds, the findings must be dated to c. 900,000 (Cueva Negra) and 780,000 BP (Zamborino).
This pushes the arrival of Acheulean to Europe back to the same date as the (believed) arrival of Pebble Culture and the oldest known H. erectus in the area (Homo georgicus, dated to c. 800,000 BP, considered intermediate between H. habilis and H. erectus, it seems).
Primitive navigation?
It also raises again the issue of whether H. erectus could have crossed the Gibraltar Strait from Africa to Europe. This was already believed based on the fact that both Pebble and Acheulean tools are found earlier in southern Iberia than further north.
But Gibraltar Strait was never totally closed in the Ice Age, so these Erectus people must have built some sort of boats or rafts to cross it. The other case suggesting some sort of boating skills in hominins is found at the other corner of Eurasia: in Flores. Homo floresiensis arrived to a remote island in Indonesia (also never directly linked to the contintent) somehow and surely it was not by means of mere swimming (how could whole bands do that, with children and everything?). These two seem to be the major documented feats of navigation by Homo species other than ours (for some reason, Neanderthals don't seem to have done anything of the like - the Bosphorus at best).
References:
· “The oldest hand-axes in Europe”. Gary R. Scott & Luis Gibert. NATURE| Vol 461|3 September 2009.
· EFE news article.
.
36 comments:
Maju. Sorry about this but I can't remember where we were discussing possible into Africa movements. This deals with an earlier period than that we were discussing but I'm sure you'll be interested. This was placed in a local paper last week and I wondered if you knew any more about it. I haven't time at the moment to follow it up:
http://www.nzherald.co.nz/history/news/article.cfm?c_id=500832&objectid=10596326
From the article: 'Speaking at the British Science Festival in Guildford, where he gave the British Council lecture, Lordkipanidze raised the prospect that Homo erectus may have evolved in Eurasia from the more primitive-looking Dmanisi population and then migrated back to Africa to eventually give rise to our own species, Homo sapiens - modern man'.
I read that in a different version.
The case is that is not even clear whether H. habilis is ancestral to H. erectus or rather a short-lived parallel line. Habilis' skull capability is very low, between 360 and 600 cc. and Richard Leakey suggested they were Australopitecines rather than an Homo species.
Whatever the case, H. georgicus, which might be indeed an evolved H. habilis, has the same age as the oldest H. erectus of Africa (KNM ER 3733, with some 850 cc of brain), so it can hardly be their ancestor.
Also you have the even older H. rudolfensis, that had a (somewhat controversial) cranial capacity of c. 700 cc.
In comparison, H. georgicus had only 600 cc., which is in the high range of H. habilis but significatively lower than its African contemporaries.
And, even if we'd ignore all that, Georgia is anyhow not that far away from Africa and probably marks the farthest expansion of the expanded H. habilis family.
There's some "Eurasian-centrism" in the media hype regarding this fossil, IMO. Neverthelss, once removed the exaggerations, it is interesting because:
1. Proves that H. habilis derivatives actually expanded out of Africa and may help to explain H. floresiensis, for instance.
2. It's apparent intermediate characteristics may support that H. habilis was indeed in the evolutionary line to humankind, and was not a parallel line, as Leakey suggested.
"Richard Leakey suggested they were Australopitecines rather than an Homo species".
I think most would agree that their classification as to either Homo or Australopithecus is fairly arbitrary. They are halfway between, probably a transitional species.
"Whatever the case, H. georgicus, which might be indeed an evolved H. habilis, has the same age as the oldest H. erectus of Africa (KNM ER 3733, with some 850 cc of brain), so it can hardly be their ancestor".
Doesn't really rule it out though. The particular fossils found are unlilkely to be either the first or the last of their species in any region. And interestingly a recent paper (which I've no doubt you read) suggested H. habilis and H. erectus were present at the same time in parts of Africa. Does suggest a separate geographical origin, although ecological speciation may provide an alternative explanation.
"Georgia is anyhow not that far away from Africa and probably marks the farthest expansion of the expanded H. habilis family".
I wouldn't be too confident in calling georgicus just a member of H. habilis, but besides that we have very early H. erectus in East and SE Asia. Perhaps they represent descendants of georgicus. Regarding dating in SE Asia:
http://anthro.palomar.edu/homo/homo_2.htm
from the link, 'Dating the Java Homo erectus fossils has been difficult. In the past, it was generally accepted that most of these bones are 700,000-200,000 years old, based roughly on what was the presumed date for the geological strata in which they were found. In 1994, however, radiometric dating of sand particles attached to two of the fossils indicated that they were actually 1.8 and 1.6 million years old. These dates indicate that some Homo erectus left Africa soon after they evolved from early transitional humans'.
And, 'Three surprisingly early Homo erectus skulls were found during the 1990's on the fringes of Eastern Europe at Dmanisi in the Republic of Georgia. They date to 1.75 million years ago and look very much like the earliest Homo erectus from Africa--i.e., those that have been classified by some researchers as Homo ergaster. This discovery lends credence to the 1.8 and 1.6 million year old dates for Homo erectus from Java and to an early rather than late Homo erectus expansion out of Africa'.
Ok. Who knows? Maybe H. erectus back-migrated to Africa with the lions and other Eurasian mammals?
Is that comment supposed to be relevant, or is it perhaps in the wrong place?
Sorry?
If you mean my comment, I can't say much more. H. erectus and in general hominins other than H. sapiens are not my main area of interest and your data is widely different than what I got browsing Wikipedia (in many cases doubling the antiquity of Eurasian settlement by hominins). So what else can I say? Maybe you are right and then maybe H. erectus colonized Africa with the lions and other species that moved from Eurasia to Africa (not sure which ones but I know that a lot of the African fauna, including lions and canids is of Eurasian origin. They must have migrated in that time more or less, I guess.
Sorry, the migration of canidae to Africa is older, from some 10 million years ago, though this may be the case of the ancestor of the lycaon, not the Abyssinian wolf, which may be more in the 3 million years range. Could not find anything about felidae but the lion seems to have evolved in Africa maybe 1.5 million years ago. Maybe I'm upon something (because lions and tigers, native to Asia, are very closely related) but very unsure.
Also I'm checking now the equidae and the ancestor of modern Equids, Plesippus, lived some 3.5 million years ago only. So the genus Equus should not be older than 3 million years or maybe less. So, yeap, it seems that some 2.5-1.5 million years ago a lot of animals moved from Eurasia to Africa, and I guess that our remote ancestors could (hypothetically) be some of them.
"your data is widely different than what I got browsing Wikipedia (in many cases doubling the antiquity of Eurasian settlement by hominins)".
I haven't checked Wiki but I've long accepted (at least 10 years) the dates given in the links I posted. Can't understand why the editors at Wiki haven't accepted them.
"it seems that some 2.5-1.5 million years ago a lot of animals moved from Eurasia to Africa, and I guess that our remote ancestors could (hypothetically) be some of them".
What I originally couldn't understand was your connection of Homo movements to that of other species. Your own comments since that one have shown movements into and out of Africa do not necessarily involve multiple species. Each individual species has its own requirements and consequently moves at its own pace and in its own direction.
Although it's possible that ancient humans may have attached themselves to migrating herds it's doubtful that they have ever followed game into new regions, in fact the opposite seems more likely: game followed humans. For example the Asian bison was able to enter America once humans had eliminated the long-horned bison. Humans may have entered new regions where game they had previously hunted already existed of course.
Consequently members of the Homo genus could have moved into or out of Africa at many various times, as they have done over the last 40,000 years or so.
As long as it's not "many times" (and not just two or three) and as long as you abide to the apparent archaeological evidence, I'm ok with that.
I do not think this changes anything in regard to the shared ancestry of Neanderthals and AMHs (where is where I think you want to reach): in any case it could push the date further back to that possible back-migration into Africa some 1.8 million years ago.
"I do not think this changes anything in regard to the shared ancestry of Neanderthals and AMHs".
It might do. Gene flow both into and out of Africa, not to mention through the rest of the world, is actually the most rational explanation for all stages of our evolution from Australopithecus. It's a fair bet that the suite of genes that separates modern humans from Australopithecus did not arise just within a single small population isolated in some small region in Africa all that time.
Those who believe the myth of a single origin for each individual species and subspecies are forced to claim that the hybridisation demonstrated within the dabbling duck genus is a 'special' case. Probably the only thing 'special' about the ducks is that many more intermediate species have survived through both time and space than is normal. Intermediates within most groups of species have simply failed to survive.
Once one accpets that there's nothing 'special' about the dabbling ducks it's easy to see that the evolution of all species and subspecies can most simply be interpreted as being a result of similar hybridisation and gene flow. Genes flow through related species and subspecies.
The straw man argument raised against this idea is that gene flow is inadequate to explain the relatively short time periods involved in some cases. But that straw man argument ignores migration. Migration would speed up gene flow immensely. We shouldn't expect for a moment to find archeological evidence for such migrations though. For the most part it would have involved genetic exchange between similar groups with very similar technologies, perhaps usually from regions of population growth into regions of inbred populations. Advantageous genes would eventually spread widely. It's more than just possible that modern humans carry genes that Neanderthals or their ancestors took into Africa.
You are always going around that issue.
What I see is that Neanders and AMHs are very different (skull, legs, body... and genome too) and that archaeology seems to suggest that they evolved from geographically differentiated branches of H. erectus. So whenever H. erectus split between the Eurasian and African branches, that's the point of divergence of our two species, regardless of whatever anecdotal fucking and introgression.
If Neanders and us would have been close cousins, then most likely both species would have merged. But they did not, so guess we were different enough for fusion to be highly difficult (if not plainly impossible).
"So whenever H. erectus split between the Eurasian and African branches, that's the point of divergence of our two species, regardless of whatever anecdotal fucking and introgression".
Sorry. I forgot. All species have remained completely separate from the moment they were created.
From the moment they diverged? Not necesarily, but if they evolved in places as remote from each other as East or Southern Africa one and Europe the other, for some 900,000 years or maybe (with your data) as much as 1.8 million years, then my statement stands true most probably and your last reply is nothing but whining.
Some people seem to have a crede of the Neanderthal-ness of either modern Homo sapiens or just European ones (why not West and Central Asians, I wonder) that they seem to have difficulty dropping even if the evidence has mounted up to extreme heights against that belief. Even there are some who insist with no evidence that whatever evolved H. erectus found in Africa and possibly in the line to H. sapiens is "H. heidelbergensis", again with no evidence or criterium whatsoever. I just can't accept all that nonsense.
I am quite persuaded that the evidence indicates since long ago (but much more now) that the two Homo species evolved separately but parallely from a very remote shared ancestor known as H. erectus. I though that difference was of only 900,000 years or so but you seem to have evidence suggesting it may be even doubly older. Ok: it's you the one throwing rocks on your roof, not me.
"What I see is that Neanders and AMHs are very different".
That's exactly what most Europeans said when they first made contact with Australian Aborigines.
"Some people seem to have a crede of the Neanderthal-ness of either modern Homo sapiens or just European ones (why not West and Central Asians, I wonder)".
West and Central Asians actually demonstrate more 'Neanderthal-ness', or at least mixture, than do Europeans. And it actually makes sense that they would.
"Not necesarily, but if they evolved in places as remote from each other as East or Southern Africa one and Europe the other, for some 900,000 years or maybe (with your data) as much as 1.8 million years, then my statement stands true most probably and your last reply is nothing but whining".
I actually argue a more recent common ancestry, as you would have noted if you had actually read what I wrote. But whatever species is the common ancestor that species must, at some stage, have stretched from Africa, through the Middle East to Europe. It presumably formed a cline of population made up of a series of smaller groups, something like the localised tribal groups so often the subject of Dienekes' blogs. At the extreme geographic margins they would have become as different as are the people at the different margins of the modern human species' distribution.
Of course it's quite possible the cline could have eventually been broken in the middle through ecological change. But before then genes could flow freely back and forth within the species (whatever that species was, possibly a hybrid of H. erectus and H. heidelbergensis anyway).
In spite of your claims to the contrary we do have indications of ancient genetic expansion either into or out of Africa, probably similar to the ones responsible for the worldwide distribution of modern haplogroups. For example the Acheulian, Mousterian and Levallois technological expansions. Are you suggesting these expansions were in no way accompanied by genetic expansion? or that the technologies arose independently right across their distribution? I'll admit these three technological expansions failed to reach East Asia, or SE Asia where H. erectus and the pre-Acheulian tools survived until about 30,000 years ago. And H. floresiensis until possibly 10,000 years ago.
The claim is frequently made that there is no evidence of hybrid formation. In fact there is ample evidence. It's just that the idea of hybrids is so unacceptable for some reason that alternastive explanations are quickly sought. Any single piece of evidence can have several possible explanations so this is usually very easy to do. But the explanations are often collectively contradictory.
It's quite obvious to me that the sort of genetic expansions and replacement we can so easily trace in the modern human species are actually much more ancient than being just confined to the modern human period. In fact just such genetic expansions are what has driven our evolution, along with that of every other species and subspecies. In other words we humans don't all come from some small, inbred tribe from Africa who remained isolated for more than a million years, to emerge triumphant somewhere between 100k and 40k (the indecision as to the dating alone surely speaks volumes). Makes a comfortable myth though.
That's exactly what most Europeans said when they first made contact with Australian Aborigines.
Nonsense comparison. They are also very different from Australian Aborigines, and from Mungo Man himself too!
They are very different in a scientific sense too: their chest, muscles, extemities, face, head... but of course they are not that different if compared with chimpanzees or whatever more distant common cousin.
But when comparing with H. erectus then I'm never really sure if it's Erectus or Neanderthal who is closer to us. In brain capacity and some modern behaviour it's Neanderthals, but in the rest not really.
West and Central Asians actually demonstrate more 'Neanderthal-ness', or at least mixture, than do Europeans. And it actually makes sense that they would.
Europeans are essentially a subset of West/Central Asians, I don't know why we should be "less Neanderthal". But anyhow West/Central Asians don't look Neanderthal at all.
To be Neanderthal-looking you'd have to have short extremities (legs and arms), a very stocky and incredibly strong constitution, including very thick bones, an extreme low vault with extreme dolicocephaly and a cone-shaped thoracic cavity, much wider towards the belly than towards the shoulders (ours is always much more tending to a cylinder). There's short stocky people but even if they may remind somewhat of how Neanders may have looked, the rest of their traits is human and they'd be mere wimps for a Neanderthal.
Neanderthals were probably like the dwarves of modern fantasy setups: small, stocky, slow but incredibly strong. But their heads and faces would be more different from ours than these fantatstic criatures'.
I think I have a neutral attitude towards Neanders and other Homo spp. and while I do see H. sapiens "archaic" traits here and there, I've never seen any Neanderthal trait in any extant human population.
But whatever species is the common ancestor that species must, at some stage, have stretched from Africa, through the Middle East to Europe. It presumably formed a cline of population made up of a series of smaller groups, something like the localised tribal groups so often the subject of Dienekes' blogs. At the extreme geographic margins they would have become as different as are the people at the different margins of the modern human species' distribution.
Nope.
There's no reason for them to form a cline if the path of the original migration is more or less strictly blocked. They'd rather diverge as virtually isolated groups, even if there was sporadic contact every some 100,000 years or so.
The Nile itself, the only more or less continuous path in and out of Africa south of the Sahara, seems to have been interrupted in its flow several times in the course of Homo spp. history. So migrations would have been sporadic. Even if the Nile would have been there all the time, it's just a thin thread of continuity, not a wide area of contact, and you can see the effects of such barriers in modern humans, even if we have been diverging only for a fraction of a fraction in comparison to H. erectus.
Even in Eurasia there are important barriers like the Himalaya or the deserts of Central Asia. And life in the Paleolithic was pretty much isolated and tribal, not the cosmopolitan madness we're now used to. So the chances for global re-homogenization after divergence are virtually null.
For example the Acheulian, Mousterian and Levallois technological expansions.
Ok. That's about it. Acheulean and Levallois are about the same thing and the date of arrival for Acheulean to Europe is now of 900,000 BP, coincident with that of H. erectus.
There's no Mousterian in Africa south of the Sahara: the technocultures that seem to be at the root of the H. sapiens family (Sangoan) are directly evolved from Acheulean.
The claim is frequently made that there is no evidence of hybrid formation. In fact there is ample evidence. It's just that the idea of hybrids is so unacceptable for some reason that alternastive explanations are quickly sought.
For what I know the only case clearly suggestive of hybridation is the Lagar Velho kid, whose chronology is extremely late, some 10,000 after the last Neanderthal remain is known. I imagine he was a hybrid and, if so, also the evidence of Neanderthal (or other hominin in the line to Neanderthal) persistence in NW Iberia until Neolithic age or so (there's a site with Acheulean, not Mousterian, technology controversially carbon-dated to 12,000 BP at the Galician-Portuguese border and otherwise the area is devoid of documented human presence until very recently).
The rest seem essentially misclassifications based on very tiny fragments of skeleton. Even if there were other hybrids, it doesn't seem clear they could survive or have offspring themselves, and no single piece of Neanderthal DNA has been found in modern humans anyhow.
It's quite obvious to me that the sort of genetic expansions and replacement we can so easily trace in the modern human species are actually much more ancient than being just confined to the modern human period.
It's what you want to believe. Fine with me. I just cannot agree with it: I see no evidence, rather the opposite.
In other words we humans don't all come from some small, inbred tribe from Africa who remained isolated for more than a million years, to emerge triumphant somewhere between 100k and 40k (the indecision as to the dating alone surely speaks volumes). Makes a comfortable myth though.
Not "40k" for sure. 100 to 60 thousand years ago at most. And the African original group was not that "inbred" (what a silly and baseless commonplace): they had been evolving for 100,000 to 140,000 years (or more): they could not be that "inbred", just an homogeneous species, like any other.
"There's no reason for them to form a cline if the path of the original migration is more or less strictly blocked".
How the hell would they migrate in the first place if 'the path of the original migration is more or less strictly blocked'? Surely it has to be open for any migration at all to happen, and while it's open genes can move in either direction. Of course it's quite likely that 'migrations would have been sporadic' but at such times hybrid formation is more than just possible.
"Acheulean and Levallois are about the same thing and the date of arrival for Acheulean to Europe is now of 900,000 BP, coincident with that of H. erectus".
It's my understanding that the Levallois is much more recent than the Acheulian. I'll find a link in a few days as I'm off up north this morning. Anyway neither the Levallois or Acheulian is automatically associated with H. erectus as neither technology reached the east, yet H. erectus certainly did.
"100 to 60 thousand years ago at most".
Hang on. If the evidence is so completely compelling how come the postulated dating has so wide a margin of error?
"And the African original group was not that 'inbred' (what a silly and baseless commonplace): they had been evolving for 100,000 to 140,000 years (or more): they could not be that 'inbred', just an homogeneous species, like any other".
A bit of consistency is in order. One minute you're claiming they had been evolving separately for more than a million years and suddenly now it's reduced to just '100,000 to 140,000 years'. Again, if the evidence is so secure how come you can't decide anything like how long they were isolated? Besides which any small group (of any species) isolated for as long as 140,000 years, let alone a million, cannot be anything else but inbred.
"For what I know the only case clearly suggestive of hybridation is the Lagar Velho kid".
It's extremely interesting that in fact the change from archaic to modern humans through Europe and Central Asia seems to be gradual, not sudden. The earliest archaics are described as having 'archaic features'. Strange, don't you think? Take a quick look at these:
http://scienceblogs.com/strangerfruit/2007/01/humannanderthal_hybridization.php
http://www.cosmosmagazine.com/news/814/humans-and-neanderthals-interbred?page=2
http://home.entouch.net/dmd/hybrid.htm
This last a long one, mostly dealing with the 'Lagar Velho kid', but I think you'll find it interesting.
How the hell would they migrate in the first place if 'the path of the original migration is more or less strictly blocked'? Surely it has to be open for any migration at all to happen, and while it's open genes can move in either direction.
See: Sahara pump theory and Pluvial.
Genes can only flow if people flows. And even in pluvial periods, people must have flowed in one or the other direction primarily: probably it was always the generally fittest (sub-)species which expanded into the lest fit one's territory; probably generalists, who adapt better to any kind of environment could emigrate, while very locally specialized populations could not (or not so easily).
In fact that happens for other branches of the animal tree as well. Only where two closely related species share the geography, like wolf and coyote in America, can the genes flow sometimes (even if it's normally minimal and limited to some introgression because of the intrinsic inter-species barriers).
In our case, we have "short" periods of easy transit (pluvials) followed by long periods of extreme isolation (arid Sahara). We know that in the Abbasian pluvial, H. sapiens emigrated (with or without long term success) northwards but we do not have any evidence that Neanderthal or whatever other remainder H. erectus did the same southwards. They surely did not. In fact they had not even left Europe by that time.
It's my understanding that the Levallois is much more recent than the Acheulian.
Your understanding in this aspect is wrong: the levallois technique, which is not an industry in itself but sometimes serves to differentiate between sub-industries within Acheulean and Mousterian, appears at least since Middle Acheulean. It's not impossible that such a simple but useful technique could have been invented in different locations at different times.
And, as Riel Salvatore points out, the correct English spelling is Acheulean, not Acheulian. Not too important but for your interest anyhow.
"100 to 60 thousand years ago at most".
Hang on. If the evidence is so completely compelling how come the postulated dating has so wide a margin of error?-
For some it seems that there nothing that happened in Asia matters, only Europe, so they seemingly make Aurignacian equal to the OOA, which is flagrantly wrong. So forget about the 40 and even 50 kya dates: they correspond with the colonization of West Eurasia from South Asia and hence must be quite more recent than the OOA.
Another reason may be the limited availability of reliable bodily remains but that is not a valid argument anymore: you have to consider also the industrial and genetic evidence.
One minute you're claiming they had been evolving separately for more than a million years and suddenly now it's reduced to just '100,000 to 140,000 years'.
I'm talking here about the Homo sapiens species since it can be identified as such, not the precursors. With the Homo erectus/rhodesiensis phases it is at least 900,000 years, probably more.
Besides which any small group (of any species) isolated for as long as 140,000 years, let alone a million, cannot be anything else but inbred.
We don't know how small or large it was. The evidence is contradictory and the inhabited area must have included all southern and eastern Africa, which is quite a large area (not sure right now but at least as large as Europe).
It's extremely interesting that in fact the change from archaic to modern humans through Europe and Central Asia seems to be gradual, not sudden. The earliest archaics are described as having 'archaic features'. Strange, don't you think? -
Archaic doesn't mean Neanderthal, just not typically modern. I see many
"archaics" living today, they have very interesting faces but they are 100% Homo sapiens without doubt. Just having some prognathism, a marked supraorbital torus or some other craniofacial "imperfection" qualifies you as being "archaic-looking". Such traits are present today and quite common, if you bother to look around. IDK, impacted teeth or even lack of the wisdom teeth are "modern" traits, perfectly healthy wisdom teeth is "archaic".
In truth I'm not that interested in the topic. I have read some stuff in the past but right now I don't feel like reading anymore on speculations on whether this jaw piece is this or that. Honestly I don't care that much: it's just trivia after all, at least from my viewpoint. As a somewhat interesting divulgative documentary (featuring Zilhao, Mellars and Paabo, among others) concluded: it doesn't matter so much what happened to Neanderthals and the other Homo species, the fact is that today we are, for the first time, the only human species roaming the Earth.
Thanks for the links.
"Only where two closely related species share the geography, like wolf and coyote in America, can the genes flow sometimes".
Quite common actually. And once a species is able to again move into a new region interbreeding with its similar subspecies is the norm. Asian bison in North America is a good example. Mallard and grey duck hybrids in the Pacific. Anne Gilbert has a blog on the subject:
http://writersdailygrind.blogspot.com/2009/09/wolf-x-coyote-hybrids-find-niche-in.html
"the correct English spelling is Acheulean, not Acheulian".
That must be a recent change as all the textbooks I possess use the second spelling. However, as a result of that link I'll use the first.
"Your understanding in this aspect is wrong".
The following article is mildly interesting:
http://anthromuseum.missouri.edu/minigalleries/handaxes/intro.shtml
From the article, 'Later Acheulean industry, employed the Levallois technique that yielded flakes of preplanned shape and size, greatly improved the efficiency and utility of flakes as tools'. Note: Later Acheulean. Although the Acheulean knocked off flakes to make their tools it's the use of 'flakes of preplanned shape and size' that is the defining aspect of the Levallois. The Mousterian developed from that. So to a large extent they are separate developments. One of my textbooks even suggests that the Levallois developed from the Acheulean in the north of its range. So we probably have human migrations associated with technological expansions.
"so they seemingly make Aurignacian equal to the OOA, which is flagrantly wrong. So forget about the 40 and even 50 kya dates".
I agree completely with your comments here. But even if we push the date for the OoA back there is still no agreement. In other words no actual evidence for it apart from the haplogroups, which may be the result of some form of selection.
"With the Homo erectus/rhodesiensis phases it is at least 900,000 years, probably more".
So, once we include these H. sapiens ancestors we're definitely back with the inbreeding problem. That's a long time with no outside genetic input. And do you really believe that the whole suite of genetic change differentiating humans from Australopithecus occurred in just this small group?
"Archaic doesn't mean Neanderthal, just not typically modern".
OK. So what came out of Africa? 'Modern' humans or 'Archaic' humans who later turned modern across the whole world? How could this have happened? Gene flow? The 'parallel evolution' argument is inadequate to explain the phenomenon.
From your 'pluvial' link:
"In geology and climatology, a pluvial (Latin pluvilis, from pluvia, "rain") was an extended period of abundant rainfall lasting many thousands of years".
Far from your statement:
"we have 'short' periods of easy transit".
In other words we have plenty of time for mixing and back migration.
Although the Acheulean knocked off flakes to make their tools it's the use of 'flakes of preplanned shape and size' that is the defining aspect of the Levallois.
I don't see could it not have evolved in parallel in different places and times. There's no "Levallois culture" and no "Levallois industry", just a technique, widespread in zillion of different places, epochs and cultural contexts. Do you think that the fact that Native Americans farmed implies some sort of migration from the Old World? I don't. They surely invented it separately, even if it's essentially the same tech.
I agree completely with your comments here. But even if we push the date for the OoA back there is still no agreement. In other words no actual evidence for it apart from the haplogroups, which may be the result of some form of selection.
I'd need clear evidence of such selection, not just enthusiasts who believe on it kind of blindly.
There are two possibilities for the OOA:
1. It happened not long before the apparent Eurasian expansion, that is c. 70-60,000 BP, or...
2. It happened when the first H. sapiens migrated to North Africa and West Asia some 100,000 years ago.
We don't have enough info to discern that and doesn't seem that important after all because the subsequent process would be all too similar. I find that mtDNA just doesn't seem to fit well with the 100,000 BP date but I may be wrong or we may be missing some crucial data that has been lost in the depths of time accidentally.
Whatever the case with OOA, it'd seem to me (on archaeological grounds) that the arrival to India could have happened c. 75,000 BP, just before Toba. But of course that should not matter for people who disdain the "coastal model" and who think that India is just a cul-de-sac like New Guinea and not the epicenter of Eurasian expansion.
So, once we include these H. sapiens ancestors we're definitely back with the inbreeding problem. That's a long time with no outside genetic input.
Africa is a huge continent: there should have been all the time enough genetic diversity. If there was admixture it'd be with other local Homo species, not proto-Neanderthals.
Anyhow, inbreeding is not that a big problem long term because the isolated group grows its own genetic diversity, eliminating the faulty descendants in the process. Separation is in fact the main process leading to speciation: why that obsession with "inbreeding"? Nenderthals were "inbred" and they were fit and smart anyhow. All island species began as "inbred" small subgroups... they do well anyhow.
OK. So what came out of Africa? 'Modern' humans or 'Archaic' humans who later turned modern across the whole world? -
This is like a word play because the term "anatomically modern humans" is used as synonim of Homo sapiens. This does not mean that some AMH were/are not "archaic" in other senses. It's a matter of word choices.
For the purposes of this discussion, what came out of Africa were AMH, H. sapiens, archaic or not. The (mostly random) evolution of locally modern phenotypes was of course a series of local processes that happened later: in Africa and outside it.
This should be clear for you. Maybe I can spot nowadays one or two Europeans that look "Aurignacian" but most just do not: the phenotype has changed somewhat.
The 'parallel evolution' argument is inadequate to explain the phenomenon.
Let's see: Africans, Australian Natives, East Asians, Europeans, etc. are all different local variants derived from those "archaic" H. sapiens. They are different, not "parallel" but they all share the species' general traits that were also present in "archaic" modern humans.
In other words we have plenty of time for mixing and back migration.
I don't see it: if the flow was in one direction, then there was probably no counter-flow. It's a matter of fluids' pressure.
The FOXP2 gene could easily be an example of a gene that came to modern humans from Neanderthals, perhaps when they met up around 100k in the Levant. Perhaps we could regard it as a 'talking gene' (which it's presumably not simply so) to illustrate gene flow.
I presume the gene is recessive; you need two copies for it to work. So if a man or woman who could talk married someone who did not have the recessive none of their offspring could talk. However if one of these offspring married someone who could talk half their offspring would be able to talk. The advancing wave of talking humans would be preceded by a band of variable width comprising recessives. So the wave would pick up local genes as it traveled and ultimately the single gene can be said to have spread through the population independently of any other gene or genes. That's introgression. Probably quite common in the evolution of all species and subspecies.
As shown by one of Dienekes' recent posts:
http://dienekes.blogspot.com/2009/09/y-chromosomes-of-saudi-arabia.html
it's not Africans that spread around the world. It is the descendants of two women and one man who left Africa at some time, not necessarily together.
From Wikipedia:
The FOXP2 protein sequence is highly conserved. Similar FOXP2 proteins can be found in songbirds, fish, and reptiles such as alligators.[12][13] Aside from a polyglutamine tract, human FOXP2 differs from chimp FOXP2 by only two amino acids, mouse FOXP2 by only 3 amino acids, and zebra finch FOXP2 by only 7 amino acids.[14][15][16] A recent extraction of DNA from Neanderthal bones indicates that Neanderthals had the same version (allele) of the FOXP2 gene as modern humans.
What's the surprise in all this?
Stop reading Anne Gilbert or discuss with her, please!
"A recent extraction of DNA from Neanderthal bones indicates that Neanderthals had the same version (allele) of the FOXP2 gene as modern humans".
And that mutation was dated at about 80,000 years. How do you explain that?
"Africa is a huge continent: there should have been all the time enough genetic diversity".
And of that huge genetic diversity you claim that none were able to breed with any similar humans immediately outside Africa. Or were able to breed with any that had entered Africa at any time. If only it were that simple. Sounds biblically based to me.
"There are two possibilities for the OOA".
You don't get it do you? If the evidence is as clear cut as you claim there should be only one possibility, and we'd be able to prove it easily. Besides which it's just you who've narrowed it down to two possibilities. I've read plenty of other possibilities using even wider dates.
"I'd need clear evidence of such selection, not just enthusiasts who believe on it kind of blindly".
It's either selection or just one man and two women emerged from Africa.
"Anyhow, inbreeding is not that a big problem long term because the isolated group grows its own genetic diversity, eliminating the faulty descendants in the process".
Rubbish. It will be able to grow its own genetic diversity and effectively eliminate faulty descendants only if the poplulation itself is growing rapidly, otherwise it's doomed (as every person involved in saving threatened species knows). Poultry breeders are able to inbreed because they set hundreds of eggs from which they get a certain number of chicks. They are then limited to breeding from about half a dozen of those chicks, an extremely artificial situation.
"All island species began as 'inbred' small subgroups..."
Not true. Most seem to have to involve either at least two subspecies, or a large number of individuals to become viable. I agree that a level of inbreeding is necessary for us to be able to recognise species in the first place but your claim, "Nenderthals were 'inbred' and they were fit and smart anyhow" is presumably not true. That's why they're extinct.
"the term 'anatomically modern humans' is used as synonim of Homo sapiens".
That in itself is wordplay. Surely the humans that emerged from Africa were either 'anatomically modern' humans or 'archaic'. They couldn't have been both, especially as we can be fairly sure there were just a few of them.
"The (mostly random) evolution of locally modern phenotypes was of course a series of local processes that happened later".
And:
"Africans, Australian Natives, East Asians, Europeans, etc. are all different local variants derived from those 'archaic' H. sapiens. They are different, not 'parallel'".
Exactly. So you claim whatever suits your belief whenever you like. On the one hand you claim these local phenotypes all developed in parallel for the change from 'archaic' to 'modern', as did technologies of your own choosing (such as Levallois), yet you realise that separation leads to diversity. So parallel for the change from 'archaic' to 'modern' and for technological development such as Levallois, whereas we know the people and technologies in each of the regions you mention has been very different until recent times.
"It's a matter of fluids' pressure".
That pressure would only last for a short time though, perhaps a few hundred years as in the relatively recent European expansion. And movement back to Europe is commonplace already, as you're no doubt aware. You seem to believe that species are a static pheneomenon but that is far from true.
It can't be dated to 80,000 BP and make any sense: if the gene in humans and chimps only differs by TWO (2) SNPs and the divergence of these two species is of at least 8 million years, then each SNP must represent 4 or more million years of evolution.
So not just Neanderthals but all Homo spp. had that same gene. Maybe Australopithecines were only half way but Homo erectus and the others were fully human in that sense almost for sure.
And of that huge genetic diversity you claim that none were able to breed with any similar humans immediately outside Africa.
Sahara remember: Sahara! Without doubt the largest non-oceanic barrier to human mobility worldwide. The Sahara divides the World in two, it does for humans too.
You don't get it do you? If the evidence is as clear cut as you claim there should be only one possibility, and we'd be able to prove it easily.
Are we talking about the same thing? Reconstructing prehistory many dozens of thousands of years ago? Tell any prehistorian or archaeologist that their work is "easy" and should provide "easy" evidence for anything. They'll laugh!
It's either selection or just one man and two women emerged from Africa.
No. And that means you just don't understand genetics: if you have 2 lineages now it means that there were dozens maybe hundreds of them back then. Just that drift works "miracles". We have discussed drift and fixation before and I'm not going to repeat that.
You are obsessed with frocing comparisos science with the Bible. It's just sick! You look like a more or less reverse Bible-seller. Its like my friend P. who has been listening to Satanic heavy metal for way too long and, while he is agnostic/atheist, he has dreams where such Christian ideas manifest anyhow.
You have to just delete all that, embrace Pachamama and forget there is anything called Yaveh. Godforms feed by getting people thinking on them, either in positive or negative light, doesn't really matter. You have to turn off the godform Yaveh. I did long ago.
(continues)
(continued from above)
"All island species began as 'inbred' small subgroups..."
Not true. Most seem to have to involve either at least two subspecies, or a large number of individuals to become viable.
That's a curious theory. I'd like to see it demonstrated.
Darwin himself concieved his theory by observing how turtles and those small birds whose English name I can never recall, evolved divergently in each of the Galapagos islands. Even if there are exceptions to this principle, the principle clearly stands as one of the pillars of evolution theory.
That in itself is wordplay. Surely the humans that emerged from Africa were either 'anatomically modern' humans or 'archaic'. They couldn't have been both, especially as we can be fairly sure there were just a few of them.
Not so few (for sure) and it's you who is wordplaying with the words "archaic" and "modern", which are relative not absolute. I'd even say that largely subjective terms.
H. sapiens idaltu has been sometimes reconstructed as a terribly "modern" H. sapiens, even if he's the oldest specimen we know of. Naturally the more robust the skull, the more likely to be preserved, and that's why most old skulls are from really robust males. But arguing on that may be a self-fulfilling prophecy kind of reasoning, not anything too realistic.
On the one hand you claim these local phenotypes all developed in parallel for the change from 'archaic' to 'modern'...
I don't claim anything: "modern" is what we see now, even if it looks "archaic". Australian Aboriginals and Papuans often do look "archaic" but fossil Australians are in fact more "modern"-looking, so to say. "Archaic" looks are found everywhere anyhow but maybe they tend to concentrate where there's not enough genetic variability. Though hard to say anything conclussive in this regard.
That pressure would only last for a short time though...
Maybe the whole "short" time of Pluvial periods. There's always going to be a group or groups that are going to find easier, perhaps just for minimal advantages, to exploit such new niches (wet Sahara) and expand, while others may never even get to know of the wet Sahara at all, and will remain constrained to their geographical areas.
I don't see why any species or population restricted to Europe would benefit from any wet Sahara phase. Or some group living in Java either. The peoples most likely to be benefitted from such periods would be those already living near the Sahara, logically.
You have pre-concieved ideas and fight for them. But that's not what we need in a scientific debate: that's politics in fact.
"You have pre-concieved ideas and fight for them".
Maju. Your comments are always chock full of such 'pre-concieved ideas'. Some examples from here:
"and the divergence of these two species is of at least 8 million years".
Very few people would date the divergence that recently. You claim such a date because it suits your beliefs.
"The Sahara divides the World in two, it does for humans too".
Does now, but certainly is not a permanent division.
"Just that drift works 'miracles'".
I've continually noticed that your theories rely very heavily on such miracles as drift, bottlenecks and founder effect, even when it's difficult to see the action of such miracles.
"You have to just delete all that, embrace Pachamama".
You'll have to explain that but it seems like a substitute for god. I thought you claimed to be atheist.
"H. sapiens idaltu has been sometimes reconstructed as a terribly modern' H. sapiens, even if he's the oldest specimen we know of".
So he or she must have bred with less 'modern' humans. Doesn't do much for the theory that modern humans were totally different and unable to breed with their neighbours.
"That's a curious theory. I'd like to see it demonstrated".
Excellent book by Diamond and Mayr regarding birds of Melanesia. An island devastated about 500 years ago has been recolonised by birds from several other islands. The authors claim it's a common phenomenon in the formation of new subspecies. Quoting Darwin's theories regarding subspeciation on the Galapagos is not very valid these days. Anyway the finches seem to be moving round and forming subspecies there in exactly the same manner as Diamond and Mayr mentioned.
"maybe they tend to concentrate where there's not enough genetic variability".
Who's making up theories now? I think your first comment about genetic variability is correct, but isn't it more likely that elements of that genetic variability failed to reach the region?
"I don't see why any species or population restricted to Europe would benefit from any wet Sahara phase. Or some group living in Java either".
That's certainly what we call 'a red herring', a comment designed to hide from the facts. What about those living in the Levant? And they would form a cline with those in Europe, Asia and, ultimately Java. Humans, along with most other species, have never reached a region and remained there for the remainder of their existence. Even dinosaur species moved around.
"and the divergence of these two species is of at least 8 million years".
Very few people would date the divergence that recently. You claim such a date because it suits your beliefs.
Erm... Pan-Bonobo divergence... There's people using the 5 million BP date, even in serious genetics, and the usual, consensual, Wikipedia ref is at best of 7 mill. BP. I think but I'm quite unusual in this, that the divergence date must be older and have reasons to think it is in fact older, close to 10 mill. years.
So you got all wrong.
"The Sahara divides the World in two, it does for humans too".
Does now, but certainly is not a permanent division.
While it's arid, it does. And most of the time it is.
I've continually noticed that your theories rely very heavily on such miracles as drift, bottlenecks and founder effect, even when it's difficult to see the action of such miracles.
I don't ever use bottlenecks. Normal processes as founder effect and drift can explain it all. Extreme highly unlikely circumstances like a bottleneck are not necessary.
You can't talk genetics ignoring drift/FE. You just can't.
"You have to just delete all that, embrace Pachamama".
You'll have to explain that but it seems like a substitute for god. I thought you claimed to be atheist.
No, I'm Pantheist! Pachamama is anyhow how Andeans call Mother Earth, I'm surprised you did not know that. I meant: embrace Nature.
So he or she must have bred with less 'modern' humans.
No. Where do you get that idea from? I'm going to stop using the terms "archaic" and "modern" with you altogether because you just read much more in them than they really mean. A group of people will always have different more or less expressed traits, varying among the individuals and. Depending on whatever chromosome combos, and maybe even epigenetic alterations, these or those traits may be emphasized or not. Nothing of that needs the existence of two populations: even normal random drift would cause individual appearance to change. People are only identical to their clones... and even then...
Quoting Darwin's theories regarding subspeciation on the Galapagos is not very valid these days.
AFAIK, it stands: each subspecies of turtle evolved by isolation, not hybridation. I can't say that in no cases is otherwise but in most cases, for all the biology texts I've read in my life, that is the way species diverge: physical and/or reproductive isolation, which needs not to be 100% absolute, just clear enough.
I think your first comment about genetic variability is correct, but isn't it more likely that elements of that genetic variability failed to reach the region? -
What I've seen in the Australian case is that Paleolithic fossils are more "standard" than modern ones, that most specificities of Australian Aboriginals seem of recent spread, of the last 10,000 years or so. But whatever: it would not bother me whatever the way it is.
What about those living in the Levant? And they would form a cline with those in Europe, Asia and, ultimately Java. Humans, along with most other species, have never reached a region and remained there for the remainder of their existence.
Or they would not mix very much. That happens a lot when species diverge: that they do not mate anymore (or at least rarely enough as to make no real difference). We're talking many hundred thousand years of divergence.
But, well, whatever. My impression is that if the main flow goes from Africa to Asia, the backflow should be close to nil or very low anyhow. At least in principle. And that is more likely that one species displaces another, just like grey squirrels are displacing red ones in Britain, than that the two species merge. Of course there's no guarantee againts occasional interspecies mating and some introgression but that's about it.
We have very different views of how evolution works: for you it's all "breeding", while for me the more conventional view that it's dominated by mere divergence is actually true. Both may be true up to a point (i.e. I don't discard that in some cases inter-breeding co-acts within the process of divergence) but I still think that the main element is separation, not fussion.
Erratum: in second paragraph of first reply (of the last two) should read "Pan-Homo divergence", not "Pan-Bonobo".
" Both may be true up to a point".
I think we've been carrying this on long enough but I'll finish by saying that I agree with this comment. Evolution is ultimately simply the result of a combination of inbreeding and hybrid vigour. Inbreeding is necessary for a recessive gene to become expressed in any population. However inbreeding alone leads first of all to loss of fertility, so outcrossing is needed in order for the new gene to expand geographically. This outcrossing would inevitably lead to hybrid vigour in the mixed population, and so encourage an even wider spread of the by now fixed gene.
It's not just a matter of recessive genes. New mutations arise too and randomly (or by fitness selection, which also has a random element) become dominant in the small distinct population. This may also a apply to pre-existing minority genes, of course.
Inbreeding may and will probably in most cases create less fit populations (not necessarily unfertile: selection will take care of that), hence the most extended or successful populations are usually more versatile and generally fit than those isolated in islands. But there's no absolute rule and an island population/species may happen to be fitter after all.
You do see South American animals that have succeeded in North America, the same that the opposite happens too. It depends of the particular cases and what do they find when they finally can expand.
Most of the time speciation that would eventually affect all the globe did not happen in small islands but in large continental land masses (for land animals, of course), where sufficient diversity existed to begin with and where it could be generated anew if this was not the case. But there are enough cases of widespread animals that have succeeded first in a continent other than the largest one, so there are many random incalculable factors at play.
Enjoy.
"New mutations arise too and randomly ... become dominant in the small distinct population".
They can become dominant only once previously dominant genes die out, which (I agree) is more likely to happen in 'the small distinct population'.
"the most extended or successful populations are usually more versatile and generally fit than those isolated in islands".
Exactly. And precisely because they contain a wider gene pool and therefore display a level of hybrid vigour.
"speciation that would eventually affect all the globe did not happen in small islands but in large continental land masses (for land animals, of course), where sufficient diversity existed to begin with".
And that diversity derives from ... (see above).
Oh. I nearly forgot:
"There's people using the 5 million BP date, even in serious genetics, and the usual, consensual, Wikipedia ref is at best of 7 mill. BP. I think but I'm quite unusual in this".
That's what I said. You claim more even than the Wiki reference. Because it fits your belief.
Because I'm not easily persuaded by mere consensus. Would have we always worked by such principles we would have died off like Neanderthals probably or at best remained stuck in superstitious beliefs. Innovation lies in rebelliousness and the ability to not just reproduce but to add from your own creativity even often going back to scratch.
Who bothers in connecting the fact that the bonobo-chimp divergence is larger than we used to think, to the almost direct implication on the Pan-Homo split (typically evaluated in its lowest possible figures) also being older? That's why I exist, I guess: to say: "hey guys and gals, you are missing something important here". Someone more influential than I am may take note and make the paradigm change. That's my hope at least.
You can go back a couple of centuries and tell the same to your dearly Charles Darwin: "Hey, Charly, Wikipedia... erm, I mean, the Bible says this and that and everybody seems to agree. Charly, you're blinded by your own faith".
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