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Author Topic:   Overkill, Overchill, Overill? Megafaunal extinction causes
Mammuthus
Member (Idle past 4820 days)
Posts: 3085
From: Munich, Germany
Joined: 08-09-2002


Message 31 of 64 (61732)
10-20-2003 4:59 AM
Reply to: Message 26 by wmscott
10-17-2003 2:12 PM


quote:
I am astounded that work as important as yours is so severely neglected and underfunded. I think you are probably barking up the wrong tree, but how will we ever know unless you are able to find out? I would very much like to see your work completed, I would like to know if you are right or not.

Hi wmscott,
Thanks for the encouragement. I don't feel particularly put upon. I did successfully get money a couple of times from private donors and from the NSF. But we never had a big enough operation to go thoroughly through all the fossils. This may happen in the future though as a couple of other ancient biomolecule groups have been sounding interested lately.

quote:
On the problem of climate change being asynchronous throughout that period yet extinctions were simultaneous, a sudden abrupt large rise in sea level would of course be simultaneous all over the world. Simultaneous extinctions are easy for a flood model to deal with, the problem is with progressive extinctions that are believed to have occurred over time towards the end of the ice age. But we must be careful not to over simplify, before the flood event there may have been other factors at work, perhaps even your super bug, that may have caused a number of extinctions.

How would a flooding model explain the expansion of the grasslands in North America and the increase in population size of several other species of herbivore such as buffalo and several species of cervids?

quote:
There may have been smaller abrupt changes in sea level leading up to the big one, that caused some extinctions in animals who's habit was limited to low elevations. Plus we have to remember that there is some noise in the data and what may appear to have been asynchronous may have been simultaneous.

There is a lot of noise in the data to be sure. However, Wrangel Island is particularly vexing. The bones date from anyhere between 20 and 30 Kya to 4.5 Kya whereas just a few km away in Siberia the record stops at 9.5 Kya. This suggests the climate change was asynchronous.

quote:
The surviver problem is solved by remembering that there would have been scattered 'islands' of survival. North America seems to have been particularly hard hit, many of the large animals that we have today are actually recent arrivals from the old world.

For some species such as muskoxen that is correct. They apparently survived in isolated refugia. But buffalo and most cervids did not and to my knowledge, there is no evidence of a genetic bottleneck at this time.

quote:

The ice age humans didn't do any better, take a look at the difference between ice age skulls and modern populations in those same areas, the modern populations are nearly always the result of later migration. As demonstrated by the complete lack of Neandertal survival and complete lack of even their DNA in modern populations, there was a human bottle neck as well. The extinction event hit the hunters as well as the hunted, which throws a monkey wrench into both the overkill theory and the 'overill' theory as well.

A problem with using neandertals as an example is two fold 1) the evidence is very thin that there was no interbreeding (see my arguments in the Neandertal thread) 2) All neandertal fossils studied to date predate the end Pleistocene extinctions by about 20 K years. So whatever happened was in Europe and independent of the end Pleitocene megafaunal extinctions.

The origin of the human genetic bottleneck is unknown but I do not believe it dates to the appropriate time period i.e. end Pleistocene. If anything, H. sapiens was an expanding population at that time.

In any case, all three hypotheses are full of holes currently which makes both research and debate rather interesting.


This message is a reply to:
 Message 26 by wmscott, posted 10-17-2003 2:12 PM wmscott has responded

Replies to this message:
 Message 35 by wmscott, posted 10-20-2003 9:30 PM Mammuthus has responded

  
Quetzal
Member (Idle past 4217 days)
Posts: 3228
Joined: 01-09-2002


Message 32 of 64 (61736)
10-20-2003 5:46 AM
Reply to: Message 30 by Mammuthus
10-20-2003 4:42 AM


Hey, O Hairy One,

Some of your reply was cross-posted with stuff I had.

On this bit, however:

So the other cyclical changes since the Pliocene where humans were not involved but extinction did occur could not have involved climate change? And I don't know that the extinctions at the end of the last ice age dwarfed previous die offs...the curious aspect of the end Pleistocene die offs was that they so specifically involved megafauna.

Especially the Late Miocene extinction pulse (the Hamphellian event) ~5 mya. Around 60 genera went extinct in North America, of which 35 IIRC were classed as megafauna (compared to 40 genera all told in the Pleistocene event). Globally, 10 of 18 equids, the Indricotheriidae, etc, all bit the dust. Some of it might be climatic (expansion of grasslands obliterating the habitat for browsers). Some of it was due to competition with newly evolved organisms. This latter is what did in the indricotheres, for example - competition with mastodonts and mammoths (bloody elephants ). Although vaguely correlated with large scale climate change (this is the one all the overchill folks point constantly to), there were obviously other factors than just climate change involved.

However, it supports your reference to non-human factors.


This message is a reply to:
 Message 30 by Mammuthus, posted 10-20-2003 4:42 AM Mammuthus has not yet responded

  
Rei
Member (Idle past 5357 days)
Posts: 1546
From: Iowa City, IA
Joined: 09-03-2003


Message 33 of 64 (61792)
10-20-2003 3:19 PM
Reply to: Message 30 by Mammuthus
10-20-2003 4:42 AM


quote:
So there is no evidence because the population was sparse and disperesed but there were so many millions of people simultaneously hunting mammoths that they caused their extinction?

Are you deliberately being like this? You know very well that 12 million people scattered across over 16 million square miles is under one person per square mile - i.e., scattered bands.

quote:
In addition you propose a hypothesis is valid because NO evidence is left behind? So I guess if 10,000 kill sites are found next week overkill will be invalidated?

My god, Mammuthus, this is annoying. Please, if you're going to keep indirectly asserting that you would *expect* to find even a measurable percentage of the kill sites in 16 million square miles of land, then please explain why, or stop asserting it. Point to where even elephant kill sites from 100 years ago are found in Africa. We know that elephants were heavily hunted in Africa 100 years ago. Where are the sites? Kill sites typically preserve rather poorly, because they are not buried quickly, as a general rule. Gary Haynes (an archeologist who has studied modern elephants, and elephants in the fossil record) discussed how between 1984 and 1986 he saw 9,000 elephants culled, and has been unable to find any of their bones anymore. In reference to Clovis, "In fact, 15 sites with 50 mammoths dead in them to me is an extremely rich, enormously rich, archaeological record, of something going on over a very brief period."

quote:
And sorry, while you are correct that most mammoths are represented by bone there are tons of skin samples and some almost fully preserved carcasses including Dima from which I have personally observed brain, liver, intestine, heart, blood, etc.

My claim was that bones are a lot more common than skin, and that what skin remains is typically in poor preservation. Do you have a specific counter to this assertion? I'm sure you're quite familiar with the big dissapointment that was Zharkov.

quote:
Then where is the huge genetic bottleneck in all of these species? Bovids, nope, equids nope, canids, nope...cervids, nope..muskoxen, sure though it is hard to determine if they had a bottleneck at all and some work I am doing right now suggests not.

Nice assertion. Do you have anything to back it up with, or is it pure conjecture? The work that you're doing "suggests not"? Can you give an example?

quote:
It is relatively small compared to the area from Europe to Mexico where every single last one of the largest megafauna became extinct.

And as I pointed out and you didn't address, Moas are about 1/23rd of the size of the Mammoths, and so would be expected to be much more stable in smaller populations.

quote:
And in fact for moa extinctions habitat destruction is considered just as plausible as hunting

Whoah, look what we have here! Habitat destruction, hunting, and other mixed causes - of which hunting is one of them. Exactly what I have suggested this entire time.

Are you familiar with the quite common cooking sites filled with butchered Moa bones? Holdaway and Jacomb's population study paper which shows that from hunting alone a population of 158,000 moas (in an area the size of Arizona) would be dead within 160 years? Any of this? Here's a quick summary article:

http://www.archaeology.org/magazine.php?page=online/features/moa/index

Now this is odd... I reference heavy environmental destruction by both an island tribe, and a continental tribe, and you respond with:

quote:
Which shows how different an island is from continental populations.

Please explain how you got this. Do you not know who the Anasazi were?

quote:
Considering you have been writing as if I am a stupid fuck for even challenging the holy overkill hypothesis I figured I would demonstrate that not everybody is convinced and that an anonymous internet forum poster such as myself represent the only skeptics...

I do not mean to sound as if I am insulting your intelligence, Mammothus. However, there are things you need to address. You still haven't explained why you would expect to find all of the kill sites when the land area in discussion is over 16 million square miles. You haven't explained how you get that the ratio of megafauna kill site fossils and megafauna fossils that otherwise show evidence of hunting, to other fossils during this same brief time period, suggests that hunting wasn't a major factor. You've yet to address the ample evidence of massive environmental destruction by native peoples, continental and island. Etc. You can see why I would be insistant on getting answers on these things from you. My apologies if it sounds insulting.

quote:
So the other cyclical changes since the Pliocene where humans were not involved but extinction did occur could not have involved climate change? And I don't know that the extinctions at the end of the last ice age dwarfed previous die offs...the curious aspect of the end Pleistocene die offs was that they so specifically involved megafauna.

Are you actually trying to claim that this is related to climate change? All of the major human 'invasions' occured at different times (Australia, New Zealand, Madagascar (all 3 not during a time of climate change), North America, etc); the Northern latitudes in the Americas had their bust before the Southern latitudes; the Ice Age was already on the decline during the American dieoffs; islands that weren't colonized with humans didn't experience the dieoffs (the Galapagos, Reunion, the Seychelles, Lord Howe, etc) until recent times; etc. Also, are you trying to actually claim that the Pliestocene extinctions weren't incredibly exceptional for extinctions during periods of climatic change in recorded history? A whooping 43% of North America's mammal genera went extinct during this extinction. 91% of the animals that went extinct were greater than 5 kilograms, and 73% were greater than 44 kilograms. In South America, 46 genera died, 80% were greater than 44 kg. Europe only had 13 genera go extinct, and I'm not aware of any in Africa during this time period.

The sad thing is that Wooly Mammoths might have made it, if not for the discovery by humans of Wrangel Island about 6,000 years ago. As soon as humans find it, the mammoths dissapear.

quote:
So all of Europe to Mexico, where most of the megafauna that went extinct was concentrated, was artic?

They arrived in the New World from the arctic - their culture must have had to be completely adapted to survival in such cold climates to survive - including getting most of their diet from hunting. When expanding further south, you seem to just expect them to suddenly change culture and start farming or whatnot (what do you propose they did for food after getting used to a mostly meat diet, in an area filled with abundant large game animals?)

quote:
The gatherers would still supply a more predictable supply of calories than the hunters...and if a single mammoth could supply the group for weeks, why would they kill every single one and all of the other megafauna (except for all the other megafauna that they left alone)..never prey switch either when the density of one species got to low to be worth it?

Are you familiar with the extinction of the passenger pigeon? Humans didn't kill every last passenger pigeon - not even close. However, once the population was damaged enough, it was unable to recover. People prey-switched on Moas, also, but they still went extinct. The archaeological evidence switches from butchered moas to other game and shellfish.

quote:
What equilibrium with humans? At this time humans were mass migrating all over the place. You had bountiful megafauna in Africa. What possible selection against killing them all would be in Africa that did not exist outside of Africa?

What "unusual" migrations were occuring during this period, at a rate fast enough to disrupt long-standing human cultural stances?

quote:
So 10,000 years go by and then Europeans hunt elephants with guns and for the first time put the species under pressure....what is the evidence for up down cycles in elephants prior to this?

How many times do I have to point out that humans, and human culture, coevolved with elephants in Africa? Whether there were up and down cycles is irrelevant (do you have counterevidence?), although yes, one would expect small up and down cycles. Even a most nomadic tribe taking on highly destructive social memes isn't a threat to elephants in general - just in their particular region.

quote:
It certainly does not show up in the genetic record to my knowledge...quite a bit of variation still is present suggesting a huge effective population size was present prior to the recent hunting pressure

I'm not arguing that elephants were nearly wiped out by natives. I'm arguing that because of coevolution, that they *weren't*, and that there would just be the typical up and down cycles, nothing dramatic. *You* were the one arguing about instability, and I was mentioning that the population change that you referred to was due to a new population coming in, with a new "land of plenty" situation - europeans with guns, and the ivory trade.

quote:
For some of their prey. But humans (if you don't accept multiregionalism) evolved in a single part of Africa and spread...why didnt they overkill as they spread out? Elephas maximus in India should have been wiped out. Land of plenty, no people, left Africa 4 million years before, did not co-evolve with humans...yet no overkill.

You seem to expect *every* species that humans encounter to get hunted out of existance. That seems pretty preposterous to me. Different animals live in different types of geographic environments, and with different organizational structures. Furthermore, one would expect that the more recent migrants from Africa would still retain more of the social structure that they lived on before, while the further in the arctic they get, the more their culture will become dependant on hunting the abundant wild game.

quote:
Interesting then that moose (the only animals tested thus far) learned in one generation to avoid predators.

How do you come to the conclusion that they learned in *one generation*?

quote:
But that is what would have to be believed to accept overkill since they left lots of megafauna alone that were still in abundance.

Provide one piece of evidence that they were "left alone". They weren't hunted to extinction. That hardly means that they were "left alone".

quote:
Hunting a food source to extinction is not particularly compelling.

Even the hunting-only people (which, again, I am not one*) seldom believe that the species were hunted to extinction - only that they were hunted to the point where they were unable to recover.

quote:
Oh really? And what is the evidence for this? elphants can reach tremendous population densities. So can other large herbivores...smaller populations than rats? Maybe, but small populations? the evidence runs against that.

Please, Mammothus. You know very well that the ability to sustain an animal is generally relative to its size (at least, I *assume* that you do). The more massive it is, the more calories it needs to consume, and the smaller its population will be (on average).

quote:
Should not have to, most of the late mammoth finds are in areas that are not permafrost so the kill sites should be easy to stumble over.

Actually, I would expect them to be harder, because they won't preserve as well.

quote:
Except you have made clear you discount anything related to climate or pathogens as factors...in your response to Quetzal

Better work on improving those reading skills. I'll quote:

quote:
'm not saying that it's impossible for a species to go extinct from a disease - but I think the species has to be in *severe* trouble already before this can happen. This does not describe the megafauna at all - they were very widespread, across all kinds of climates. Disease may have been a "finishing blow", or something that perhaps weakened their populations, but disease - or even disease and climate together - causing this? Doesn't seem likely.

Sounds like I'm advocating a "multiple causes" hypothesis, doesn't it? I'm stating that disease and climate together isn't enough - what also is needed is changes in population through hunting of the animals, hunting predators, hunting prey, etc; altering of the flora; etc.

quote:
Depends, if you are immunologically naive and the population densities are as low as you have been claiming all you have to do is kill off the young (which are more suceptible anyway) and in a generation the population has collapsed.

Yes. "Only have to kill of the young". Now, where has this happened to cause a species to go extinct?

quote:
Even mild viruses can have a huge impact on megafauna for example elephant herpes of Loxodonta is often fatal to Elephas. The two genera can no longer be housed together (if you want a successful breeding program or dont want to blow the zoo budget on gancylovir).

I'll repeat. Now where has this happened to cause a species to go extinct?

quote:
We have had megafaunal extinctions on the scale of the end Pleistocene in the last 10 K years? Please present this data. It would be a Science paper at the very least and a discovery of the century.

They need not be on the scale of the end of the Pleistocene. What you are asking for is essentially impossible, since humans had, after this, moved into all of the world's major land masses. However, extinctions relative to the sizes of the land masses that were moved into after this point, clearly due to overhunting and other human-related causes, are quite observed.

------------------
"Illuminant light,
illuminate me."


This message is a reply to:
 Message 30 by Mammuthus, posted 10-20-2003 4:42 AM Mammuthus has responded

Replies to this message:
 Message 38 by Mammuthus, posted 10-21-2003 5:36 AM Rei has responded

  
Rei
Member (Idle past 5357 days)
Posts: 1546
From: Iowa City, IA
Joined: 09-03-2003


Message 34 of 64 (61794)
10-20-2003 3:55 PM
Reply to: Message 29 by Quetzal
10-20-2003 4:07 AM


Quetzal,

First off, you'll notice that the first thing I did in my response to you was to thank you for your hyperdisease example. Secondly, I apologize for pigeonholing you into the role of a defender of the disease-only hypothesis; as you'll notice, the same is happening to me concerning kill-only. I do believe that disease may well have played a role, but that it hardly could be blamed, even with climate, for what we witness at the end of the Pliestocene.

quote:
it was an example of a pathogen that countered your assertion that no such pathogen exists

Which I thanked you for. It would be nice if you would at least acknowledge humility.

quote:
Your argument, that rinderpest hasnt been established in NA or New Zealand is specious IOW, so what?

That wasn't my argument at all. Read again. I quote:

quote:
That doesn't mean that some other disease could have been the culrpit, but I would expect that we would see at least some New World reminant of whatever disease it was.
(emphasis added)

quote:
In the case of the Late Pleistocene event, even in areas which were unsuitable for human habitation, isolated or relictual populations were ALSO decimated.

I would be curious as to what sort of regions you are thinking of here, in which evidence of megafauna exists.

quote:
Im sorry, but no matter effectively a group of humans managed to extirpate multiple species in the constrained space of an island using primitive, essentially hand tools (and theres little question that the Maori accomplished that feat in a couple of centuries on New Zealand),

Or faster. And note that New Zealand is the size of Arizona. I don't have range plots for the various megafauna, and I know that many were widespread, but I wouldn't be surprised if there were at least a couple who had a range that size.

quote:
Although its pretty fruitless to speculate on effective population size in a large migratory species like Mamuthus primogenus, overall were talking about (on two continents) at a minimum 10^7 to 10^9 individual animals eliminated in around 1-2000 years when you take all the different species into consideration.

I'll accept those numbers, although it should be noted that, if mammoths spread in a manner similar to elephants in Africa, I would expect much closer to the 10^7 number for them. Also, one expects the lower ranges on carnivores which, while not as large, need to eat from a much larger prey base.

And yet, how many moa would you expect in such a lush environment as New Zealand, the size of Arizona? They're a tiny fraction of the size of mammoths. I think the only reasonable argument that you could make against them is that there was geographically less area for humans to fill, but that argument only lasts so long in a continental situation.

Again, also, keep in mind that many populations are unstable once they get damaged (such as passenger pigeons proved to be).

quote:
it strikes me that the blitzkrieg hypothesis is asking more from human hunters than they are capable of. How many humans are we talking about?

Assuming a population growth rate of 4 births that make it to adulthood (in this environment without as many human diseases, with plentiful game) per woman, from a source of 10,000 people they could reach about 1e34 in 2000 years. Clearly birth rate isn't a problem - the issue is how much resources are there for people to survive on. Initially, there are vast resources. Consequently, one expects, in the absense of social memes preventing it, a population boom.

quote:
And they didnt miss a single population?

They missed Wrangel Island until about 6,000 years ago - I mean, that was the time of the Pharaohs. The fact is, they had tons of time to find all of the remaining populations. And again, I don't advocate overkill as being the only reason; just one reason.

quote:
Worse, the overkill hypothesis ignores the fact that numerous species DIDNT disappear that would be as easy or easier to kill than mammoths, for example. Why didnt the American bison disappear? Too many of them? What about caribou, elk, mule deer, etc etc. These were harder to hunt than mammoth or ground sloth?

Smaller animals in general survived the Pliestocene better than large ones. For many reasons, humans have historically prefered to hunt large animals when they are capable of it, whether for food, for ritual, or for sport. Also, needing to be explained by people who do not consider overkill as part of the cause of the extinction, is why the extinction was so heavily focused on large animals.

quote:
Those few undisputed tool-marked bones could just as easily have been worked AFTER death: Clovis-as-scavenger vice Clovis-as-hunter.

I'm familiar with the theory, but that wouldn't explain the massive spear points designed to be mounted on massive spears that have been found. Perhaps one might argue that they went after the young or sick, but they clearly were killing these massive animals.

quote:
However, your belief that humans abruptly behaviorally adapted to a radically different lifestyle in spite of the fact that there remained a wide variety of prey species they could have continued to massively over-exploit requires even more assumptions than hyperdisease.

Again, for the last time, I do *not* believe that it was an abrupt change - that's Mammothus's suggestion. I believe that it was steady natural selection. It sometimes feels like I'm debating with creationists here, and their "So why do these species changes just appear in the fossil record? Did the animals just suddenly decide to evolve?"

quote:
However, it was an counterexample to your assertion that no species had ever gone extinct through disease not that this was a hyperdisease.

That seems like a rather unfair argument. If the last Steller's Sea Cow had died of pneumonia, would we claim that pneumonia wiped out the species?

quote:
but specifically the extinction of Bufo periglenes,

Bufo periglenes once occupied a region only 4km^2 - hardly a stable species. To make matters worse, they had a very rain-sensitive breeding cycle. Their population crashed in 1987 due to unusual rainfall - only 29 toads were known to have survived out of 30,000.

http://animaldiversity.ummz.umich.edu/accounts/bufo/b._periglenes$narrative.html

Please name another species, preferably one that wasn't already essentially extinct.

------------------
"Illuminant light,
illuminate me."


This message is a reply to:
 Message 29 by Quetzal, posted 10-20-2003 4:07 AM Quetzal has responded

Replies to this message:
 Message 39 by Quetzal, posted 10-21-2003 6:09 AM Rei has responded

  
wmscott
Member (Idle past 4592 days)
Posts: 580
From: Sussex, WI USA
Joined: 12-19-2001


Message 35 of 64 (61843)
10-20-2003 9:30 PM
Reply to: Message 31 by Mammuthus
10-20-2003 4:59 AM


Dear Mammuthus;

I am very glad to hear that others are interested in following up in your area, your work is far too important to be neglected.

The expansion of the grasslands in North America and other changes around the globe are of course result of climate change and possibly also the influence of changes in grazing animals. On the extinction of the Pleistocene large animals while the buffalo increased, the absence of competition would have resulted in explosive growth among the survivers and establishment of a post ige age simplified ecological balance. The buffalo survived and exploded, the apparent lack of genetic bottleneck maybe the result of comparison with animals which may have suffered the same crimp in their populations, our yardstick may be bent or sufficient surviving diverse groups prevented the formation of a bottleneck. The Wrangel Island Mammoths may represent an isolated pocket of survival, some animals may have survived on floating ice. The Wrangel Island mammoths may represent the out come of a bad roll of the dice for the mammoths, if the supposed drifting mammoths had grounded on the nearby Siberian coast instead, perhaps they would be nearly as common today as they were in the Pleistocene. On the other hand, perhaps there is just a dating problem that has created the paradox of the Wrangel Island mammoths. I am suspicious about the precision with which we know when certain events occurred in the past. Like the 20k gap between the disappearance of Neandertal and the end of the Pleistocene, I find it more plausible that considering the scarcity of Neandertal remains that we are just missing some from that time and they were killed off by whatever killed off the animals rather then creating a second mystery on how they disappeared as well. How could they just disappear and take all their genes with them? The idea of Homo Sapiens Sapiens taking out Homo Sapiens Neanderthalensis is ridiculous, the average Neandertal could have taken the average Sapiens and twisted him into a pretzel. With greater brain capacity and much greater strength, Neandertal had a huge advantage, thinking otherwise is simply pure sapiens arrogance. Without the effect of the Pleistocene extinction event, I would have predicted the opposite out come, which means we may owe our very existence to this past event.

Neandertal may not just be a old world problem, the Clovis spear points found in North America are similar to points used by Neandertal hunters in Europe, one source in talking about some bone fragments found in the state of Nebraska states. "probably ten or twelve individual skulls represented in this loess bone bed and that comparison shows them to be of the Neanderthal type, with thick cranial walls." (The Cambridge Encyclopedia Of Archaeology, p.100?) Evidence such as this and the scarcity of humanoid fossils points to the very real possibly that the Clovis artifacts are of Neandertal origin. Then there is also the Australian ice age population that consisted of two groups, an "ultramodern" group and a "robust" group with features that seem to have a possible Neandertal type influence. Then both these groups disappeared without leaving any descendants. "Examination of these Pleistocene remains has shown that all of them lie outside the range of contemporary Aboriginal skeletal variation, but in two very different directions." (The Cambridge Encyclopedia Of Archaeology, p.100) The Australian Aborigines are the descendants of later immigration and are not descended from the earlier populations. On the world in general in regard to modern populations and ice age populations one source states. "Using present techniques, it seems difficult to ascertain reliable resemblance's between skulls older than 10-12 KY and modern regional specimens from the same or a related area." (The History and Geography of Human Genes, p.73) In other words, there has been a global population replacement as the result of the pleistocene extinction event having an impact on mankind, which considering the size of it's impact on the animal kingdom, shouldn't come as a surprise.

Your very intelligent statement of, "In any case, all three hypotheses are full of holes currently which makes both research and debate rather interesting." is right on the money, my theory has it's holes as well, as you have pointed out, but I believe that with research those holes can be plugged. So far my findings of marine diatoms at an elevation of 1000 ft here in Wisconsin in the center of the North American continent shows that there was a very substantial marine transgression event at the end of the ice age when the extinctions are said to have occurred, it seems highly likely that it had a key role in those extinctions. It will take more very interesting research to measure the extent of the impact of this late ice age marine transgression on the Pleistocene extinctions. I suspect marine flooding will turn out to be the major cause.

Wm Scott Anderson


This message is a reply to:
 Message 31 by Mammuthus, posted 10-20-2003 4:59 AM Mammuthus has responded

Replies to this message:
 Message 36 by Rei, posted 10-20-2003 10:18 PM wmscott has not yet responded
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 Message 42 by Mammuthus, posted 10-21-2003 7:22 AM wmscott has responded
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Rei
Member (Idle past 5357 days)
Posts: 1546
From: Iowa City, IA
Joined: 09-03-2003


Message 36 of 64 (61847)
10-20-2003 10:18 PM
Reply to: Message 35 by wmscott
10-20-2003 9:30 PM


Good post. I just wanted to mention something:

quote:
The idea of Homo Sapiens Sapiens taking out Homo Sapiens Neanderthalensis is ridiculous, the average Neandertal could have taken the average Sapiens and twisted him into a pretzel. With greater brain capacity and much greater strength, Neandertal had a huge advantage, thinking otherwise is simply pure sapiens arrogance.

Quite true, the average neanderthal was stronger and far more resiliant than the average cro-magnon, although the greater numbers of our species per tribal group probably at least balanced that out, if not shifting it in our favor.

However, on the brain capacity front, there are a number of animals that have larger brains than us - for example, most dolphins. However, when you study their brain under an MRI, you find a much simpler internal structure. The size of the brain isn't the most important thing when it comes to intelligence. Parrots are quite intelligent, and can learn things such as being able to recognize the difference between similar objects (size, shape, color, etc) and understand the concept of "names" for objects, and yet have tiny brains.

If we could get a neanderthal brain, I would be all over that, it would really be facinating I write software that is used to study MRI images for a living. I bet there's lots of grad students that work in the lab here who would give their right arm (figuratively) to be able to write their thesis on that.

One of the reasons that archaeologists suspect that neanderthals weren't as intelligent as homo sapiens sapiens is that their tools hardly evolved over the duration of their existance.

------------------
"Illuminant light,
illuminate me."


This message is a reply to:
 Message 35 by wmscott, posted 10-20-2003 9:30 PM wmscott has not yet responded

  
Speel-yi
Inactive Member


Message 37 of 64 (61889)
10-21-2003 4:07 AM
Reply to: Message 35 by wmscott
10-20-2003 9:30 PM


quote:
The idea of Homo Sapiens Sapiens taking out Homo Sapiens Neanderthalensis is ridiculous, the average Neandertal could have taken the average Sapiens and twisted him into a pretzel. With greater brain capacity and much greater strength, Neandertal had a huge advantage, thinking otherwise is simply pure sapiens arrogance. Without the effect of the Pleistocene extinction event, I would have predicted the opposite out come, which means we may owe our very existence to this past event.

Modern man is build for speed, a Neanderthal would have had to catch the sapiens first. Then you have some other thing showing up like hafted weapons. Sapiens could kill from a distance, end of story.

Anyway, just for grins. Try a Google on inca bone and/or shoveled inscisors for some comparisons about regional differences in populations. Wish I could show you guys some stuff about the Yuki from California, they definately had some Neanderthal features.


This message is a reply to:
 Message 35 by wmscott, posted 10-20-2003 9:30 PM wmscott has not yet responded

  
Mammuthus
Member (Idle past 4820 days)
Posts: 3085
From: Munich, Germany
Joined: 08-09-2002


Message 38 of 64 (61898)
10-21-2003 5:36 AM
Reply to: Message 33 by Rei
10-20-2003 3:19 PM


quote:
Are you deliberately being like this? You know very well that 12 million people scattered across over 16 million square miles is under one person per square mile - i.e., scattered bands.

Deliberately being like what? You are arguing polar opposites. You first argue that there are so many people around at this point in history that they can hunt down every last breeding pair of mammoths and multiple other species of megafauna yet are so sparsely distributed "scattered bands", that no evidence could possibley exist that they killed ALL of these megafaunal species. Either the density was high enough for them to hunt the megafauna to extinction in which case one would expect to see evidence of such pervasive hunting or the density was much lower which provides no logical way that so few people would have killed off so many animals in so short a time.

quote:
My god, Mammuthus, this is annoying. Please, if you're going to keep indirectly asserting that you would *expect* to find even a measurable percentage of the kill sites in 16 million square miles of land, then please explain why, or stop asserting it.

Hmmm, overill is critcized because of lack of evidence for what you and others "expect" to find yet I am not allowed to ask for evidence of mass hunting? I suppose then that because of lack of evidence for 12 million human inhabitants in North America at the end Pleistocene that this is good evidence that they were there? Don't you see that you are supporting a hypothesis that only thrives on LACK of evidence. You keep repeating this and then are defensive about the fact that there is virtually NO evidence for the scenario.

quote:

Point to where even elephant kill sites from 100 years ago are found in Africa. We know that elephants were heavily hunted in Africa 100 years ago. Where are the sites? Kill sites typically preserve rather poorly, because they are not buried quickly, as a general rule. Gary Haynes (an archeologist who has studied modern elephants, and elephants in the fossil record) discussed how between 1984 and 1986 he saw 9,000 elephants culled, and has been unable to find any of their bones anymore. In reference to Clovis, "In fact, 15 sites with 50 mammoths dead in them to me is an extremely rich, enormously rich, archaeological record, of something going on over a very brief period."

15 sites with 50 mammoths and this is the sum total evidence that 12 million people inhabited North America and caused the extinction of the megafauna at the end Pleistocene. Do you really find this compelling? Case closed, Alroy can send us all home? Would you accept such tenuous support if it were a hypothesis you did not like? The culled elephants in Haynes studies were also collected for their ivory as Haynes notably leaves out of his comparison

Haynes first "Clovis mammoth sites are supposed to be rare. I think we can refute that pretty easily. I think Paul Martin originally, in his talk here, said something about something that I've told him, that there have been thousands and thousands of elephants killed -- not only in clearing of land for agricultural use, but in culling operations. In 1984, '85 and '86 I saw 9,000 elephants culled, and I cannot find a single site anymore of their bones -- within 10 to 15 years they're all gone. And I saw this happening within three months of every year, over those three-year periods."...but then

"Now, let me go to my Zimbabwe work, to my own fieldwork, because that's the viewpoint I can tell you the best, or the most about. Most of what I have produced seems to be used to support the climate-change-only model of explaining extinction. Now, admittedly, a lot of it actually does point that way very clearly. For example, if you look at the mammoth sites in the fossil record, and you look at modern elephant sites -- the ones that have been documented during culling or other noncultural death events -- they look very much alike. The same kinds of age profiles are represented in the fossil and the modern elephants; the same kind of geomorphic locations -- not at big rivers or big waterholes, or whatever -- these are at headwater locations, rather small streams.

There's lots of different species represented -- it's not only elephant or mammoth. There's large masses of bone; there's bone that looks like it could be broken artifactually, or broken to make something out of. And another point that oftentimes is not raised when comparing the modern elephant population depletion during the ivory-hunting craze of 100 years ago is that, in spite of the fact that many elephant populations were driven to about zero -- at least to a virtual zero point -- during the ivory-hunting phase of late 19th century southern Africa, they've recovered to some of the highest densities anywhere in Africa within a hundred years. So elephants can recover from overhunting. How could Clovis people, with spear points, have hunted an entire population of mammoths in North America to extinction, if people with high-powered rifles couldn't do it in the late 19th century?"

So, ivory collectors would have just left these culled elephants alone? They just dump the culled bones, don't burn them? How is this similar to what Clovis would use the bones for i.e. in Siberia you can find huts constructed from mammoth bones, why not in North America where all of these Rambo killers should have been building skyscrapers with the excess of bone they would have had available? And note, you are now switching from the immense use the mammoth carcasses would have to Clovis people to they just killed the mammoths and dumped them for fun so that all evidence for them conveniently disappeared.

quote:
My claim was that bones are a lot more common than skin, and that what skin remains is typically in poor preservation. Do you have a specific counter to this assertion? I'm sure you're quite familiar with the big dissapointment that was Zharkov.

Which part of Jarkov do you mean? The skin I have in my freezer or the bone marrow? Or the disappoitment that it was not a grown version of Dima? Jarkov was badly overhyped. The Pilot site mammoth and the ones that are not reported except to museums are much more interesting not to mention well preserved.

quote:
Nice assertion. Do you have anything to back it up with, or is it pure conjecture? The work that you're doing "suggests not"? Can you give an example?

What assertion? I asked you to give an example and you claim it is my assertion..nice evasion there Mr. Williams

Lets see..bovids..no obvious bottlenecks

Immunogenetics. 1997;46(3):237-44. Related Articles, Links

Analysis of genetic diversity at the DQA loci in African cattle: evidence for a BoLA-DQA3 locus.

Ballingall KT, Luyai A, McKeever DJ.

International Livestock Research Institute (ILRI), Box 30709, Nairobi, Kenya.

We describe the development of a polymerase chain reaction (PCR)-based approach for analysis of genetic diversity at the DQA loci in African Bos indicus and Bos taurus cattle. This approach, equally effective in European and Asian cattle breeds, detects the presence or absence of DQA1 and most duplicated DQA2 genes. Nucleotide and predicted amino acid sequence analysis of the highly polymorphic second exons, in addition to analysis of the locus-specific and relatively non-polymorphic transmembrane, cytoplasmic, and 3-prime untranslated regions, has provided evidence for considerable diversity between each of the duplicated DQA2 genes. Therefore, we propose the designation BoLA-DQA3 for the previously unpublished alleles at the second DQA2 locus. Fourteen distinct PCR restriction fragment length polymorphism (RFLP) patterns, each identifying families of alleles at three DQA loci, can be distinguished. Nucleotide sequence analysis of new PCR-RFLP patterns from 193 Kenyan Boran, Ethiopian Arsi (B. indicus), and Guinean N'Dama (B. taurus) cattle identified 13 DQA1 alleles within eight major allelic families, five DQA2 alleles within a single allelic family, and seven DQA3 alleles within three major allelic families.

not in horses either

Science. 2001 Jan 19;291(5503):474-7. Related Articles, Links

Comment in:
Science. 2001 Apr 13;292(5515):218-9.
Science. 2001 Jan 19;291(5503):412.

Widespread origins of domestic horse lineages.

Vila C, Leonard JA, Gotherstrom A, Marklund S, Sandberg K, Liden K, Wayne RK, Ellegren H.

Department of Evolutionary Biology, Uppsala University, Norbyvagen 18D, S-75236 Uppsala, Sweden. carles.vila@ebc.uu.se

Domestication entails control of wild species and is generally regarded as a complex process confined to a restricted area and culture. Previous DNA sequence analyses of several domestic species have suggested only a limited number of origination events. We analyzed mitochondrial DNA (mtDNA) control region sequences of 191 domestic horses and found a high diversity of matrilines. Sequence analysis of equids from archaeological sites and late Pleistocene deposits showed that this diversity was not due to an accelerated mutation rate or an ancient domestication event. Consequently, high mtDNA sequence diversity of horses implies an unprecedented and widespread integration of matrilines and an extensive utilization and taming of wild horses. However, genetic variation at nuclear markers is partitioned among horse breeds and may reflect sex-biased dispersal and breeding.

moose did have a bottleneck but in eurasia and at the wrong time..

Genetika. 2002 Aug;38(8):1125-32. Related Articles, Links

[Genetic diversity of moose (Alces alces L.) in Eurasia]

[Article in Russian]

Udina IG, Danilkin AA, Boeskorov GG.

N. I. Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991 Russia. udi@vigg.ru

Polymorphism of nucleotide sequence of D-loop fragment of the mitochondrial DNA was studied in 20 moose from several local populations on the territory of Eurasia. Three main haplotype variants of D-loop were detected by molecular phylogenetic method, which formed three clusters named European, Asian and American. Intraspecies variation in the length of HVSI of D-loop of the mitochondrial DNA of moose was revealed. In the Far Eastern and Yakutian moose, haplotypes with a 75-bp deletion were found, which were most similar with haplotypes (also with the deletion), earlier observed in North American moose [1]. The highest diversity of the haplotypes of mitochondrial DNA is characteristic of Yakutia and the Far East (where three haplotype variants were found), which demonstrates the probable role of the region as the center of the species or as the region of ancient population mixture. The geographic region might be considered as a probable source of ancient moose migrations from Asia to America, basing on the data of distribution of mitochondrial haplotypes of D-loop and alleles of MhcAlal-DRB1. Divergence of nucleotide sequences of haplotypes with the 75-bp deletion (forming the American cluster on the phylogenetic tree) was the lowest (0.4%), which evidences respectively recent origin of the group of haplotypes. In Europe, only haplotypes of mitochondrial DNA referred to European variant were observed. Basing on analysis of variation of nucleotide sequences of D-loop, exon 4 of kappa-Casein and exon 2 of MhcALal-DRB1, we demonstrated that Eurasian moose studied belong to the unique species, which has probably passed through a bottle neck. The time of the origin of modern diversity of D-loop haplotypes of the species was estimated as 0.075-0.15 Myr ago.

canids either

J Hered. 1999 Jan-Feb;90(1):71-7. Related Articles, Links

Phylogenetic relationships, evolution, and genetic diversity of the domestic dog.

Vila C, Maldonado JE, Wayne RK.

Department of Biology, University of California, Los Angeles, USA. Carles.Vila@bmc.uu.se

The spectacular diversity in size, conformation, and pelage that characterizes the domestic dog reflects not only the intensity of artificial selection but ultimately the genetic variability of founding populations. Here we review past molecular genetic data that are relevant to understanding the origin and phylogenetic relationships of the dog. DNA-DNA hybridization data show that the dog family Canidae diverged about 50 million years ago from other carnivore families. In contrast, the extant canids are very closely related and diverged from a common ancestor about 10 million years ago. The evidence supporting a close relationship of dogs with gray wolves is overwhelming. However, dogs are remarkably diverse in mitochondrial and nuclear genes. Mitochondrial DNA analysis suggests a more ancient origin of dogs than has been indicated by the fossil record. In addition, dogs have originated from or interbred with wolves throughout their history at different times and different places. We test the possibility of an independent domestication event in North America by analysis of mtDNA variation in the Xoloitzcuintli. This unusual breed is believed to have been kept isolated for thousands of years and may be one of the most ancient breeds in North America. Our results do not support a New World domestication of dogs nor a close association of the Xoloitzcuintli with other hair-less breeds of dogs. Despite their phenotypic uniformity, the Xoloitzcuintli has a surprisingly high level of mtDNA sequence variation. Other breeds are also genetically diverse, suggesting that dog breeds were often founded with a large number of dogs from outbred populations.

My muskoxen data is not yet published so I am not putting it here.

I can go on and on with this but can you provide a clear cut example of ALL surviving megafauna going through a genetic bottleneck? If not, why did the hunters leave such a bounty alone? Your assertion is they were also attacking the other megafauna...can you back it up?

quote:
And as I pointed out and you didn't address, Moas are about 1/23rd of the size of the Mammoths, and so would be expected to be much more stable in smaller populations.

Any reference for this?

quote:
Whoah, look what we have here! Habitat destruction, hunting, and other mixed causes - of which hunting is one of them. Exactly what I have suggested this entire time.

Are you familiar with the quite common cooking sites filled with butchered Moa bones? Holdaway and Jacomb's population study paper which shows that from hunting alone a population of 158,000 moas (in an area the size of Arizona) would be dead within 160 years? Any of this? Here's a quick summary article:

http://www.archaeology.org/magazine.php?page=online/features/moa/index

Now this is odd... I reference heavy environmental destruction by both an island tribe, and a continental tribe, and you respond with:

quote:
--------------------------------------------------------------------------------
Which shows how different an island is from continental populations.
--------------------------------------------------------------------------------

Please explain how you got this. Do you not know who the Anasazi were?


Easy, on an island where are the refugia? Do you really think comparing and island population is identical to continental? If so why is there an entire subdiscipline dealing with island extinctions?

Relevant Publications: MacPhee, R.D.E. and P.A. Marx. 1997. The 40,000-year plague: Humans, hyperdisease, and first-contact extinctions. Pp. 169-217. In: Natural Change and Human Impact in Madagascar, S. Goodman and B. Patterson (eds.). Washington, D.C.: Smithsonian Institution Press. MacPhee, R.D.E. and C.E. Flemming. Mammalian extinctions since AD 1500: A preliminary census. In: The Living Planet in Crisis, J.L. Cracraft and F. Grifo (eds.). New York: Columbia University Press, in press.

Extinction: Complexity of Assessing Risk
In discussing the extinction risk of naïve prey species confronted by reintroduced predators (Science's Compass, 9 Feb., p. 997), J. L. Gittleman and M. E. Gompper say that, apparently because of diverse anthropogenic impacts, "a markedly higher proportion of ungulate species compared with other mammalian taxa have become extinct in the past 500 years."
Not so. Although the belief seems to be widespread that large mammals such as ungulates have suffered substantial losses during the modern era (that is, the last five centuries), the facts lead to a different conclusion. Of the ~90 well-corroborated extinctions that have occurred at the species level within Mammalia during the past 500 years (1), only five species (6%) are members of Ungulata, when the broadest available cladistic definition of this taxon is used (2): two Malagasy hippos (Hippopotamus madagascariensis and H. lemerlei, both extinct around 1500); a North Pacific sirenian (Hydrodamalis gigas, extinct by 1768); and two African bovids (Hippotragus leucophaeus, extinct by 1800, and Gazella rufina, extinct before 1894). Of these, the first three are reasonably regarded as "first contact" extinctions, although the role of human overhunting in forcing these losses is evident only in the case of the sirenian. There is no meaningful evidence regarding the cause of loss of the two African bovids (1).

Getting the numbers right is important because extinction (loss of all members of a minimally diagnosable evolutionary unit) is a phenomenon in its own right, although it is often treated as merely the final stage of endangerment. Rating schemes, like the IUCN Red List, that attempt to assign extinction risk factors to endangered species are, of course, extremely important as possible guides to the planet's biotic future. But history is also important, even if its lessons are slippery. For example, the nature and cause of end-Pleistocene extinctions in the continental New World, which Gittleman and Gompper cite for their probative value, are in fact still obscure. If human overhunting of behaviorally naïve species were mostly to blame for these losses [amounting to 130 species by our count (1)], how is it that during the past 10,000 years, there have been only two mammalian species-level extinctions (a Mexican cottontail and the sea mink) in the continental Americas--despite significant habitat destruction, numerous exotic introductions, and severe persecution of many species throughout this period. This pattern suggests that we should be looking for other factors as well in first-contact extinctions (3). So who has suffered most among mammals in recent times· More than 50% of all species-level losses in the past 500 years are rodents; the groups next most affected are insectivores (13%) and chiropters (bats) (10%). Mammals of large body size (>44 kilograms) account for ~12% of modern-era species losses across all taxa (1). In other words, modern-era mammalian losses have been overwhelmingly minifaunal rather than megafaunal. And they have been overwhelmingly insular: the world's islands have been much more severely affected by species-level extinctions in recent times than have any continental biotopes, including the world's rainforests. If these patterns continue, it is the small, the island-bound, and the least charismatic that will continue to suffer most.

So Islands and continents are not different? Why is island biodiversity different then..or is this a Syamsu arugment that there are no real differences among any group, species, etc.?

quote:
Exactly what I have suggested this entire time.

Where have you been suggesting a mixed approach? You have been claiming that absence of evidence for overkill is not harmful to the hypothesis, that my having any expectations of evidence is ridiculous, you have only defended overkill as the singular cause and then merely handwave in a few references to multicausation at the end of your posts. Where have you supported environmental change having an impact? As I recall you were as dismissive of my refering to climate as you have been to anything else I have said.

quote:
I do not mean to sound as if I am insulting your intelligence, Mammothus. However, there are things you need to address. You still haven't explained why you would expect to find all of the kill sites when the land area in discussion is over 16 million square miles.

Because you cannot have such a low population density AND wipe out all the megafauna and leave no trace. And what is the possible use of an untestable unfalsifiable hypothesis? If lack of evidence and presence of absence both support overkill then it is useless scientifically.

quote:

You haven't explained how you get that the ratio of megafauna kill site fossils and megafauna fossils that otherwise show evidence of hunting, to other fossils during this same brief time period, suggests that hunting wasn't a major factor.

15 sites with 50 bones that cannot even be distinguished from scavaging? A kill site cannot even be confirmed. Why do the tens of thousands of mammoth finds (mostly dating around the relevant time period due to preservation constraints) show natural death causes and not hunting? The ratio you ask for is overwhelmingly against overkill.

quote:
You've yet to address the ample evidence of massive environmental destruction by native peoples, continental and island. Etc. You can see why I would be insistant on getting answers on these things from you. My apologies if it sounds insulting.

Yet you have dismissed every question I ask of you as purely stupid. That is what is insulting. Not that you challenge them. In any case, is there evidence of continental wide environmental impacts in the relevant areas for extinction? Again, evidence for human populations is sparse in this time period. You yourself say they would have been very dispersed. So how would that support human environmental impacts causing such massive ecological trauma? I have yet to read anyone proposing this in the extincition literature for continents so I am wondering where you get your support for this scenario.

quote:
Are you actually trying to claim that this is related to climate change?

I said prior to the end Pleistocene extinctions there was massive movement of animals between the continents and multiple mass extinction events. This was before humans even left Africa so how could they have been a proximate cause? Mammuthus colombi (not the woolly mammoth) entered North America about 1 million years ago. The extinctions subsequent to this could not have been human initiated. There have been mass extinctions without humans on the scene as Quetzal also pointed out. So what you are addressing is unclear.

quote:
The sad thing is that Wooly Mammoths might have made it, if not for the discovery by humans of Wrangel Island about 6,000 years ago. As soon as humans find it, the mammoths dissapear.

And interesting that the little evidence for humans on Wrangel Island show they were a fishing culture...and in a place where mammoths are so well preserved that you can stumble over the bones in every river and they contain bone marrow and have skin, there is not a single butchered find.

quote:
They arrived in the New World from the arctic - their culture must have had to be completely adapted to survival in such cold climates to survive - including getting most of their diet from hunting. When expanding further south, you seem to just expect them to suddenly change culture and start farming or whatnot (what do you propose they did for food after getting used to a mostly meat diet, in an area filled with abundant large game animals?)

No, I do not expect them to start farming. But then where would you get a number of 12 million? Is there a single nomadic purely hunting group that has ever reached a population size like this? Even in Africa? And the arctic they were adapted to is not like Nanook of the North. There is a short growing season where gathering would be possible. And hunting as a sole source of survival in the artic would never have allowed for population explosion.

Of course some of the controversial much older dated sites in the Americas for human habitation also screw this scenario up...but also take overill as a cause out as well.

Oh yes, and the origin of the humans that entered the new world is not thought to have been the arctic but may have been in several waves and as far south as Mongolia so it is completely unclear that it was arctic adapted nomads who colonized Beringia and North America.

quote:
Are you familiar with the extinction of the passenger pigeon? Humans didn't kill every last passenger pigeon - not even close. However, once the population was damaged enough, it was unable to recover. People prey-switched on Moas, also, but they still went extinct. The archaeological evidence switches from butchered moas to other game and shellfish.

You familiar with the elephant seal or the cheetah? They suffered almost complete extinction and were able to bounce back. There has hardly been a megafaunal extinction since the end Pleistocene.

quote:
What "unusual" migrations were occuring during this period, at a rate fast enough to disrupt long-standing human cultural stances?

Oh things like this which show very little equilibrium

BMC Genet. 2003 Oct 16 [Epub ahead of print]. Links

Mitochondrial DNA transit between West Asia and North Africa inferred from U6 phylogeography.

Maca-Meyer N, Gonzalez AM, Pestano J, Flores C, Larruga JM, Cabrera VM.

Background: World-wide phylogeographic distribution of human complete mitochondrial DNA sequences suggested a West Asian origin for the autochthonous North African lineage U6. We report here a more detailed analysis of this lineage, unraveling successive expansions that affected not only Africa but neighboring regions such as the Near East, the Iberian Peninsula and the Canary Islands.Results: Divergence times, geographic origin and expansions of the U6 mitochondrial DNA clade, have been deduced from the analysis of 14 complete U6 sequences, and 56 different haplotypes, characterized by hypervariable segment sequences and RFLPs. Conclusions: The most probable origin of the proto-U6 lineage was the Near East. Around 30,000 years ago it spread to North Africa where it represents a signature of regional continuity. Subgroup U6a reflects the first African expansion from the Maghrib returning to the east in Paleolithic times. Derivative clade U6a1 signals a posterior movement from East Africa back to the Maghrib and the Near East. This migration coincides with the probable Afroasiatic linguistic expansion. U6b and U6c clades, restricted to West Africa, had more localized expansions. U6b probably reached the Iberian Peninsula during the Capsian diffusion in North Africa. Two autochthonous derivatives of these clades (U6b1 and U6c1) indicate the arrival of North African settlers to the Canarian Archipelago in prehistoric times, most probably due to the Saharan desiccation. The absence of these Canarian lineages nowadays in Africa suggests important demographic movements in the western area of this Continent.

Eur J Hum Genet. 2003 Oct 8 [Epub ahead of print]. Related Articles, Links

Human X-chromosomal lineages in Europe reveal Middle Eastern and Asiatic contacts.

Xiao FX, Yotova V, Zietkiewicz E, Lovell A, Gehl D, Bourgeois S, Moreau C, Spanaki C, Plaitakis A, Moisan JP, Labuda D.

1Centre de Recherche, Hopital Sainte-Justine, Montreal, Quebec, Canada.

Within Europe, classical genetic markers, nuclear autosomal and Y-chromosome DNA polymorphisms display an east-west frequency gradient. This has been taken as evidence for the westward migration of Neolithic farmers from the Middle East. In contrast, most studies of mtDNA variation in Europe and the Middle East have not revealed clinal distributions. Here we report an analysis of dys44 haplotypes, consisting of 35 polymorphisms on an 8 kb segment of the dystrophin gene on Xp21, in a sample of 1203 Eurasian chromosomes. Our results do not show a significant genetic structure in Europe, though when Middle Eastern samples are included a very low but significant genetic structure, rooted in Middle Eastern heterogeneity, is observed. This structure was not correlated to either geography or language, indicating that neither of these factors are a barrier to gene flow within Europe and/or the Middle East. Spatial autocorrelation analysis did not show clinal variation from the Middle East to Europe, though an underlying and ancient east-west cline across the Eurasian continent was detected. Clines provide a strong signal of ancient major population migration(s), and we suggest that the observed cline likely resulted from an ancient, bifurcating migration out of Africa that influenced the colonizing of Europe, Asia and the Americas. Our study reveals that, in addition to settlements from the Near East, Europe has been influenced by other major population movements, such as expansion(s) from Asia, as well as by recent gene flow from within Europe and the Middle East.European Journal of Human Genetics advance online publication, 8 October 2003; doi:10.1038/sj.ejhg.5201097

There has never been equilibrium

quote:
How many times do I have to point out that humans, and human culture, coevolved with elephants in Africa? Whether there were up and down cycles is irrelevant (do you have counterevidence?), although yes, one would expect small up and down cycles. Even a most nomadic tribe taking on highly destructive social memes isn't a threat to elephants in general - just in their particular region.

Interesting that you argue this here but have no problem assuming it for the extinction of mammoths and all the megafauna throughout Europe all the way to Patagonia....and humans actualyl had contact with all of these animals long before the end Pleistocene extinctions i.e. cave paintings, 30,000 year old bone carvings in Siberia...so they had a really bad cycle..suddenly?

quote:
I'm not arguing that elephants were nearly wiped out by natives. I'm arguing that because of coevolution, that they *weren't*, and that there would just be the typical up and down cycles, nothing dramatic. *You* were the one arguing about instability, and I was mentioning that the population change that you referred to was due to a new population coming in, with a new "land of plenty" situation - europeans with guns, and the ivory trade.

What is the negative selection agianst the natives? Co-evolution is not enough as any mutation/behavior that provides an advantage should spread rapidly...why would they not have recognized their own land of plenty..especially if you argue that there were cycles where they did? What would have brought them back to not doing it? Why is there no evidence that they did do it? Also African culture is not monolithic. There are some groups that hunt elephants, others that do not. You cannot tell me that hunters in the Congo are anything like the !Kung.

quote:
You seem to expect *every* species that humans encounter to get hunted out of existance. That seems pretty preposterous to me. Different animals live in different types of geographic environments, and with different organizational structures. Furthermore, one would expect that the more recent migrants from Africa would still retain more of the social structure that they lived on before, while the further in the arctic they get, the more their culture will become dependant on hunting the abundant wild game.

As preposterous as hunting a single species to extinction as it become harder and harder to find yet ignoring other species that are abundant and that we know humans have also hunted since the same time period. And not everything that went extinct was in the arctic. The youngest fossils for many of these species do not occur at the highest latitudes. And mammoths and a lot of the extinct megafauna were nowhere near the arctic or not exclusively. Giant ground sloths certainly were not.

quote:
How do you come to the conclusion that they learned in *one generation*?

from the paper I cited "Although prey that had been unfamiliar with dangerous predators for as few as 50 to 130 years were highly vulnerable to initial encounters, behavioral adjustments to reduce predation transpired within a single generation. "

quote:
Provide one piece of evidence that they were "left alone". They weren't hunted to extinction. That hardly means that they were "left alone".

See the genetic diversity papers...no sign of any bottleneck in the time that all the megafauna is going extinct. Significant hunting would leave an imprint especially given it was not very long ago.

quote:
Even the hunting-only people (which, again, I am not one*) seldom believe that the species were hunted to extinction - only that they were hunted to the point where they were unable to recover.

What point would that be? Seriously, a single breeding pair may have all that had been left of the cheetah yet they are not extinct. Elephant seals were decimated, they are stil there...no whales have gone extinct.

quote:
Please, Mammothus. You know very well that the ability to sustain an animal is generally relative to its size (at least, I *assume* that you do). The more massive it is, the more calories it needs to consume, and the smaller its population will be (on average).

Ok so there were not millions of buffalo, elephants in the millions, the population size of mammoths..2 maybe 3? I guess I will have to take your word for this.

quote:
Actually, I would expect them to be harder, because they won't preserve as well.

Interesting then that many major mammoth finds are in places in the US that are not permafrost. Actual habitation would be easier to find in non permafrost since the tundra tends to shift around so much that you never find fossils intact and the layers get mixed so that you cnanot do stratiography...not so outside the tundra.

quote:
Sounds like I'm advocating a "multiple causes" hypothesis, doesn't it? I'm stating that disease and climate together isn't enough - what also is needed is changes in population through hunting of the animals, hunting predators, hunting prey, etc; altering of the flora; etc.

Except that megafaunal extinctions happened frequently prior to the end Pleistocene and at times where human causes could not have been a factor..so clearly humans are not needed for extinction to occur whether they played a role in this particular extinction or not.

quote:
Yes. "Only have to kill of the young". Now, where has this happened to cause a species to go extinct?

Those of us who do not view the end Pleistocene extinctions as a closed issue are trying to find out...Peter Dazsak is doing this type of research for modern extinctions. Exactly how much do you really think is known about extinction in any case?

quote:
I'll repeat. Now where has this happened to cause a species to go extinct?

When has there been an equivalent situation to the end Pleistocene regarding immunlogically naive species? There is somne evidence that Xmas Island rats went extinct by introduction of pathogens from ship rats..we are doing the molecular work now...there is also evidence that the thylacine was brought down by disease and not purely by hunting....though some advocates claim it is still alive in the outback.

quote:
They need not be on the scale of the end of the Pleistocene. What you are asking for is essentially impossible, since humans had, after this, moved into all of the world's major land masses. However, extinctions relative to the sizes of the land masses that were moved into after this point, clearly due to overhunting and other human-related causes, are quite observed.

Why would they not be on this scale? Land of plenty..no negative selection...human population only recently became so tremendous...overkill should have been widely supportable yet write up a list of the number of megafauna that went extinct at the end Pleistocene and then do the same for the time since then..what do you think you see?


This message is a reply to:
 Message 33 by Rei, posted 10-20-2003 3:19 PM Rei has responded

Replies to this message:
 Message 40 by Quetzal, posted 10-21-2003 6:55 AM Mammuthus has responded
 Message 46 by Rei, posted 10-21-2003 2:45 PM Mammuthus has responded

  
Quetzal
Member (Idle past 4217 days)
Posts: 3228
Joined: 01-09-2002


Message 39 of 64 (61902)
10-21-2003 6:09 AM
Reply to: Message 34 by Rei
10-20-2003 3:55 PM


That wasn't my argument at all. Read again. I quote:

That doesn't mean that some other disease could have been the culrpit, but I would expect that we would see at least some New World reminant of whatever disease it was.

I don't disagree with this portion of your statement, which of course was why I didn't address it. Curiously, in your reply you neglected to include the sentence I was actually responding to:

quote:
Thank you, Quetzal, I was not familiar with the morbillivirus. However, it is worth nothing that the virus has never established itself in North America or New Zealand. That doesn't mean that some other disease could have been the culrpit, but I would expect that we would see at least some New World reminant of whatever disease it was.
Now who's arguing like a creationist?

I would be curious as to what sort of regions you are thinking of here, in which evidence of megafauna exists.

The canyon lands of Colorado weren't apparently occupied until the Folsom Period - post extinction - which were occupied by M. columbi, for one. The Channel Islands off California (M. exilis) also show no signs of human occupancy, although the "last seen" of the species is dated around 10.8 kya (remember, I said it was a problem with both overkill and overill). Etc - basically, there are a number of areas, large or small, which would be unsuitable or unlikely for ease of human passage wherein small populations of at least one of the extinct genera could have survived. We're talking continental landmass here - anything south of the retreating ice. Even at Martin's "best speed" estimate of 20 km per year, that's a heck of a lot of territory for hunters to cover - and they would perforce be following the path of least resistance to maintain this year after year.

Or faster. And note that New Zealand is the size of Arizona. I don't have range plots for the various megafauna, and I know that many were widespread, but I wouldn't be surprised if there were at least a couple who had a range that size.

Except that simple land surface comparisons are silly without taking into consideration exactly how that land is arranged. No place on New Zealand is further than 100 km from the ocean. IOW, this is a big area, but it is constrained. A group of humans sweeping across Arizona like a panzer division would just as likely cause the animals they were attacking to retreat to New Mexico or Colorado. There was no place for the moa to retreat to. Habitat destruction coupled with over-hunting are what did in the moa - just like the elephant birds of Madagascar, or for that matter, almost everything on Easter Island. The extreme sensitivity of island populations to ecosystem disruption and extinction cannot be compared to the resiliance of continent-wide populations. Although some of the basic population dynamics concepts can transfer (c.f., the "island effect" of habitat disruption), a too-close extrapolation is misleading, especially in the case of a continent-wide extinction event.

I'll accept those numbers, although it should be noted that, if mammoths spread in a manner similar to elephants in Africa, I would expect much closer to the 10^7 number for them. Also, one expects the lower ranges on carnivores which, while not as large, need to eat from a much larger prey base.

However, I wasn't talking just mammoths (and I'd find 10^7 mammoths an unrealistically big number, even on a continent). Also, carnivore populations could be expected to decline after a lag in correlation to their prey species, so are hunters wouldn't need to necessarily kill them. The point being that it is unclear that a selective megafaunal hecatomb of this magnitude could be caused by humans armed with a stone toolkit - no matter how well designed it was for killing large game. That it WAS so designed is not in question. That it was capable of this level of mass slaughter is what we are arguing.

And yet, how many moa would you expect in such a lush environment as New Zealand, the size of Arizona? They're a tiny fraction of the size of mammoths. I think the only reasonable argument that you could make against them is that there was geographically less area for humans to fill, but that argument only lasts so long in a continental situation.

Exactly my point. Thank you for making it for me - it is entirely conceivable (and in fact fairly well-documented) that the Maori were able to practically stand shoulder-to-shoulder and sweep the entire island (when they weren't slaughtering each other, that is) in the few centuries in which they were decimating the moa. The opposite occurs on a continent.

Again, also, keep in mind that many populations are unstable once they get damaged (such as passenger pigeons proved to be).

Keep it in mind? LOL! Read my first post on this thread - that is precisely the disequilibrium model I proposed.

They missed Wrangel Island until about 6,000 years ago - I mean, that was the time of the Pharaohs. The fact is, they had tons of time to find all of the remaining populations. And again, I don't advocate overkill as being the only reason; just one reason.

Err, yeah. Except Wrangel is an isolated island in the Chuktchi Sea off Siberia. It took the paleoindians until around 8-9000 ya to cause the extinction of the megafauna on Cuba as well (had to wait until they'd figured out how to make boats.) Btw - this mitigates as well against the cultural change idea you put forward. If the local paleoindians had evolved such a marvelous cultural adaptation after they realized they'd obliterated their food sources, why did they turn around and commit the same act in Cuba 1500-2000 years later? Reversion to type? Or possibly there might be some other factor than overkill involved in the first place...?

Assuming a population growth rate of 4 births that make it to adulthood (in this environment without as many human diseases, with plentiful game) per woman, from a source of 10,000 people they could reach about 1e34 in 2000 years. Clearly birth rate isn't a problem - the issue is how much resources are there for people to survive on. Initially, there are vast resources. Consequently, one expects, in the absense of social memes preventing it, a population boom.

Is this how you derived your 16 million population in North America during the extinctions? Do you have a population estimate for the pre-Clovis inhabitants of Beringia (the Nanana culture)? Are you aware that the Lesser Dryas is correlated with severe drought in many areas (c.f. the paleoindian wells at the Blackwell Draw site) which would have reduced population growth? I hope the smiley face is an indication that you don't take this type of geometric growth pattern too seriously. And remember, these folks are not only supposed to be doubling their population roughly every generation (according to Martin), but traveling across two continents in less than 1000 years AND simultaneously wiping out multiple species of megafauna without leaving a single relict population. Pretty tall order.

Smaller animals in general survived the Pliestocene better than large ones. For many reasons, humans have historically prefered to hunt large animals when they are capable of it, whether for food, for ritual, or for sport. Also, needing to be explained by people who do not consider overkill as part of the cause of the extinction, is why the extinction was so heavily focused on large animals.

Smaller? Well, only in comparison to the mammoths, mastodonts and ground sloths. There were also a much greater number of the other, more "traditional" prey species that I mentioned - and which would be easier to hunt than mammoths. Humans are opportunistic hunters, they don't simply go after the biggest simply because they are the biggest, unless you're proposing sport or ritual as a piece of the puzzle. There ARE buffalo jumps, etc, associated with Clovis where the terrain allowed, indicating to me that they were more interested in food than anything else.

I'm familiar with the theory, but that wouldn't explain the massive spear points designed to be mounted on massive spears that have been found. Perhaps one might argue that they went after the young or sick, but they clearly were killing these massive animals.

You're misinterpreting what I said. I never argued that Clovis didn't hunt mammoth or other large game. In fact, there was an interesting experiment done a few years back by an archeologist/anthropologist that duplicated Clovis technology and used it successfully during the conservation culling of an elephant herd in Africa. I have merely maintained that overkill is not supported - the scale doesn't work, not that Clovis didn't hunt. OTOH, several sites that are suggested as mass kill sites have evidence of worked bones that are not consistent with hunting - more on the order of butchering already dead animals.

Again, for the last time, I do *not* believe that it was an abrupt change - that's Mammothus's suggestion. I believe that it was steady natural selection. It sometimes feels like I'm debating with creationists here, and their "So why do these species changes just appear in the fossil record? Did the animals just suddenly decide to evolve?"

I think "abrupt" in this context refers to the timeline of the extinctions - they started roughly around the time of first contact, continued for couple thousand years across two continents, then stopped, in spite of the fact that there remained a myriad of prey species - some of which had been readily exploited by our paleoindians at the same time they were obliterating the other megafauna. This appears to be an "abrupt" change in attitude. An attitudinal change which you have not succeeded in documenting in any way, btw. After all, as soon as our friends were able to reach other areas, they picked up their old habits (e.g., Cuba). Moreover, the extinction event, although mostly megafaunal, ALSO included rodents, giant rabbits, etc, which by no stretch can be considered megafauna.

That seems like a rather unfair argument. If the last Steller's Sea Cow had died of pneumonia, would we claim that pneumonia wiped out the species?

Oh, good grief. In the context of your one-line objection to the point - yes, it was an example. Is it compelling? Arguable. It's not an area that has received a great deal of attention at all until fairly recently (less than five years or so). So that was an example I could lay my hands on easily. You don't like it, fine. Lay out your criteria for what you want to see - with the understanding that systematic study of EID is a nearly new field overall.

Bufo periglenes once occupied a region only 4km^2 - hardly a stable species. To make matters worse, they had a very rain-sensitive breeding cycle. Their population crashed in 1987 due to unusual rainfall - only 29 toads were known to have survived out of 30,000.

Oh bloody hell. Now you're really arguing like a creationist. You want to quibble over the examples? Fine: here's a reproduction of the table from the article I cited on amphibians. Argue at will:


Chytridiomycosis

E. & S. Australia (1993-1999) Multiple montane rain forest and temperate species. Mass deaths, local extinctions, population declines. Near-extinction of Taudactylus acutirostris. Hypothesized link with global extinction of two species of gastric brooding frog (Rheobatrachus spp.).

W. Australia (1998-1999) Multiple species, predominantly the western green (or motorbike) frog (Litoria moorei) Mass deaths, population declines.

Costa Rica (1994-99) Multiple montane rain forest species and Panama. Mass deaths, local extinctions, population declines. Hypothesized link with global extinction of golden toad, Bufo periglenes.

Ecuador (1999) Montane rain forest Atelopus species, Telmatobius niger, and Gastrothecus pseustes. Unknown impact.

Arizona (1996-1997) Leopard frog (Rana yavapiensis & R. chiricahuensis). Mass deaths.

S. Arizona (1999) Leopard frog (Rana sp.). Mass deaths.

Colorado (1999) Boreal toad (Bufo boreas). Mass deaths.

Colorado (1970s) Leopard frog (Rana pipiens). Mass deaths.

Sierra Nevada, California (1970s) Yosemite toad (Bufo canorus). Mass deaths.

Ranaviral disease

United Kingdom (1992-1999) Common frog (Rana temporaria). Mass deaths, possibly population declines.

Arizona (1995) Sonoran tiger salamander (Ambystoma tigrinum stebbinsi). Mass deaths in this endangered species.

N. Dakota (1998) Tiger salamander (A. tigrinum). Mass deaths.

Maine (1998) Tiger salamander (A. maculatum). Mass deaths.

Utah (1998) Tiger salamander (A. tigrinum). Mass deaths.

Saskatchewan, Canada (1997) Tiger salamander (A. tigrinum diaboli). Mass deaths.

[This message has been edited by Quetzal, 10-21-2003]


This message is a reply to:
 Message 34 by Rei, posted 10-20-2003 3:55 PM Rei has responded

Replies to this message:
 Message 47 by Rei, posted 10-21-2003 4:19 PM Quetzal has responded

  
Quetzal
Member (Idle past 4217 days)
Posts: 3228
Joined: 01-09-2002


Message 40 of 64 (61905)
10-21-2003 6:55 AM
Reply to: Message 38 by Mammuthus
10-21-2003 5:36 AM


Just one correction here, O Extinct One:

15 sites with 50 bones that cannot even be distinguished from scavaging? A kill site cannot even be confirmed. Why do the tens of thousands of mammoth finds (mostly dating around the relevant time period due to preservation constraints) show natural death causes and not hunting? The ratio you ask for is overwhelmingly against overkill.

This isn't exactly accurate. At least four of the Arizona sites (Naco, Murray Springs, Escapule and Lehner) show pretty unequivocal evidence of mammoth kills. Naco had a mammoth with five Clovis points embedded in the chest. Lehner has a bison kill site, and Murray Springs shows both bison and a mammoth with several Clovis points inside. There's also another site (which I can't remember) that has a swamp version of a buffalo jump - apparently Clovis paleoindians herded a mixed bag of herbivores into a swamp, then slaughtered the group. It included mammoth and bison. Interestingly, the Lehner (9 remains) and Escapule (1 remain) site appears to be mostly juvenile mammoths rather than adults. Looks like they were pretty opportunistic.


This message is a reply to:
 Message 38 by Mammuthus, posted 10-21-2003 5:36 AM Mammuthus has responded

Replies to this message:
 Message 41 by Mammuthus, posted 10-21-2003 7:08 AM Quetzal has not yet responded

  
Mammuthus
Member (Idle past 4820 days)
Posts: 3085
From: Munich, Germany
Joined: 08-09-2002


Message 41 of 64 (61907)
10-21-2003 7:08 AM
Reply to: Message 40 by Quetzal
10-21-2003 6:55 AM


Thanks Q..but now we are down from 15 to 4 sites.

This message is a reply to:
 Message 40 by Quetzal, posted 10-21-2003 6:55 AM Quetzal has not yet responded

  
Mammuthus
Member (Idle past 4820 days)
Posts: 3085
From: Munich, Germany
Joined: 08-09-2002


Message 42 of 64 (61908)
10-21-2003 7:22 AM
Reply to: Message 35 by wmscott
10-20-2003 9:30 PM


Hi wmscott,
Thanks for your reply.

quote:
The buffalo survived and exploded, the apparent lack of genetic bottleneck maybe the result of comparison with animals which may have suffered the same crimp in their populations, our yardstick may be bent or sufficient surviving diverse groups prevented the formation of a bottleneck
.

It actually would not have to be in comparison to other animals that had a bottleneck. One would see very little intraindividual genetic diversity in such loci as microsatellites and using a molecular clock the time of the coaslescence of new alleles should be at the end Pleistocene. We don't see this for the relevant species. The only exception are muskoxen which are extremely genetically homogeneous. However, all bovids, equids, cervids, and canids that have been study show tremendous genetic variability that unless one accepts creationist selective group specific mega super hypermutation, should not be present if a gruop or species has suffered a bottleneck.

quote:
On the other hand, perhaps there is just a dating problem that has created the paradox of the Wrangel Island mammoths

This is very true. Even slightly more extensive dating studies show that we are missing some extremely key data

for example MacPhee et al. 2002. Radiocarbon chronologies and extinction dynamics of the late quaternary mammalian megafauna of the Taimyr Peninsula, Russian Federation. Journal of Archeological Science Vol 29, Issue 2, pp 1017-1042.

I would love to find a Taimyr mammoth dating to 4500...then all the extinction hypotheses would be in the toilet

quote:
Like the 20k gap between the disappearance of Neandertal and the end of the Pleistocene, I find it more plausible that considering the scarcity of Neandertal remains that we are just missing some from that time and they were killed off by whatever killed off the animals rather then creating a second mystery on how they disappeared as well. How could they just disappear and take all their genes with them?

I agree with you. Especially as the fossil remains are so scarce drawing dramatic inferences about what happened to them i.e. we killed them off is premature. Also, there are severe problems with the structure of the genetic studies on neandertals as is it is being peformed i.e. the cro magnon sequence was deemed "unacceptable" by the neandertal crowd because it was "too human". Fine, but then one cannot say anything about neandertal genetics either if any sequence that looks modern is excluded due to contamination fears....then a priori we will only look at and accept the divergent ones which is not an unbiased comparison...anyway, I digress.

quote:
Your very intelligent statement of, "In any case, all three hypotheses are full of holes currently which makes both research and debate rather interesting." is right on the money, my theory has it's holes as well, as you have pointed out, but I believe that with research those holes can be plugged. So far my findings of marine diatoms at an elevation of 1000 ft here in Wisconsin in the center of the North American continent shows that there was a very substantial marine transgression event at the end of the ice age when the extinctions are said to have occurred, it seems highly likely that it had a key role in those extinctions. It will take more very interesting research to measure the extent of the impact of this late ice age marine transgression on the Pleistocene extinctions. I suspect marine flooding will turn out to be the major cause.

What kind of dates are you finding or at least what is the spread of the dates for a marine transgression? Are there other sites in North America that indicate the same thing as in Wisconsin?

Cheers,
M


This message is a reply to:
 Message 35 by wmscott, posted 10-20-2003 9:30 PM wmscott has responded

Replies to this message:
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Dr Jack
Member (Idle past 449 days)
Posts: 3507
From: Leicester, England
Joined: 07-14-2003


Message 43 of 64 (61932)
10-21-2003 11:02 AM
Reply to: Message 35 by wmscott
10-20-2003 9:30 PM


The idea of Homo Sapiens Sapiens taking out Homo Sapiens Neanderthalensis is ridiculous, the average Neandertal could have taken the average Sapiens and twisted him into a pretzel. With greater brain capacity and much greater strength, Neandertal had a huge advantage, thinking otherwise is simply pure sapiens arrogance. Without the effect of the Pleistocene extinction event, I would have predicted the opposite out come, which means we may owe our very existence to this past event.

It is my understanding that Homo (Sapiens?) Neanderthalis has three major disadvantages when compared to Homo Sapiens Sapiens. We can run better. We have arms better suited to throwing. In other words we have range and mobility on our side should it come to a fight. We eat a wider variety of food (from analysis of bone data from Neanderthals - they ate a higher proportion of meat, much closer to a pure carnivour diet).

Secondly, larger brain capacity does not directly imply higher intelligence. Without external evidence I see little reason to believe Neanderthals were actually smarter than humans.


This message is a reply to:
 Message 35 by wmscott, posted 10-20-2003 9:30 PM wmscott has not yet responded

Replies to this message:
 Message 44 by Speel-yi, posted 10-21-2003 12:06 PM Dr Jack has responded

  
Speel-yi
Inactive Member


Message 44 of 64 (61942)
10-21-2003 12:06 PM
Reply to: Message 43 by Dr Jack
10-21-2003 11:02 AM


quote:
It is my understanding that Homo (Sapiens?) Neanderthalis has three major disadvantages when compared to Homo Sapiens Sapiens. We can run better. We have arms better suited to throwing. In other words we have range and mobility on our side should it come to a fight.

This is correct, Neanderthal reamins show a lot of evidence of close encounters with large animals. Lots and lots of broken bones. The modern design appears to have the advantage of speed on its side. A lot of recent focus has been in the structure of the cerebellum and its expansion in sapiens. Early erectus had a cerebellum that occupied 65 cc and moderns have about twice this capacity in that structure.

quote:
We eat a wider variety of food (from analysis of bone data from Neanderthals - they ate a higher proportion of meat, much closer to a pure carnivour diet).

Then it also appears that Neanderthal and Cro-Magnon may not have been in direct competition for resources. Yet another knock against replacement.

------------------
Bringer of fire, trickster, teacher.


This message is a reply to:
 Message 43 by Dr Jack, posted 10-21-2003 11:02 AM Dr Jack has responded

Replies to this message:
 Message 45 by Dr Jack, posted 10-21-2003 12:22 PM Speel-yi has responded

  
Dr Jack
Member (Idle past 449 days)
Posts: 3507
From: Leicester, England
Joined: 07-14-2003


Message 45 of 64 (61945)
10-21-2003 12:22 PM
Reply to: Message 44 by Speel-yi
10-21-2003 12:06 PM


Then it also appears that Neanderthal and Cro-Magnon may not have been in direct competition for resources. Yet another knock against replacement.

Hmm, I don't think that follows. While Neanderthals would require (almost) exclusively meat and Cro-Magnons wouldn't. Cro-magnon man still hunted, and probably the same kind of prey. That's pretty direct competition, and what's more only in one direction (a more successful Neanderthal would have limited impact on the more diverse diet of the Cro-Magnon while a successful Cro-Magnon would impact the main resource of a Neanderthal). I'd say that's a boon for replacement theory.


This message is a reply to:
 Message 44 by Speel-yi, posted 10-21-2003 12:06 PM Speel-yi has responded

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 Message 48 by Speel-yi, posted 10-22-2003 2:45 AM Dr Jack has not yet responded

  
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