Pre Clovis

[Fellow Traveler]

Clovis culture got to be the establishment version of peopling of the Americas. Momentum of opinion and grants, money,reputations rested on this as a be all answer. Thanks to Archeaologists such as J.M. Adovasio and Tom Dillehay et al, the quest didn't end there. The field is open and legitmate finds have lately pushed the date back thousands of years. Conservatively 16000 years.

[Dinwar]

I'm not sure what you're trying to say here. I've read a number of articles suggesting a pre-Clovis arival time for humanity into North America. Given that I stick to the peer-reviewed research (and usually the stuff recommended to my by archaeologists in my firm) I think that constitutes evidence that the view isn't exactly fringe. It may be looked down upon in some circles, but the Alvarez Hypothesis is still looked down upon in some circles.

[Kestrel]

I saw a lecture at the Denver Museum of Nature and Science last November that presented evidence of bone tools that predate the Clovis culture by thousands of years.

[Dinwar]

Originally Posted by Kestrel

I saw a lecture at the Denver Museum of Nature and Science last November that presented evidence of bone tools that predate the Clovis culture by thousands of years.

That's a significant part of the problem. I know bone spears were in use--they've been found mammoths (at least 2 that I've heard of). Problem is, bone just isn't that durable over the timescales we're talking about. Water leaches proteins out of them, and over time even bones in arid environments will become chalky and fragile. Then there's osteophagy, the consumption of bone by various animals (bones are organs, and organs are nutritious; also, bones are hard, which is important for rodents). Finally, spear points, arrow heads, knives, and the like are useful. A broken spear point can be re-shaped into an arrow head, and a busted arrow head can be re-shaped into a skinning tool. Obviously not always, but my point is recycling is critical when your source of material weighs as much as a modern automobile and you need to get up-close and personal with it.

There's a LOT working against us finding tools made out of non-lithic material (bone, wood, that sort of stuff). The fact that we've found any is amazing.

[Skeptic Ginger]

One of our local members gave a talk on this to our Seattle Skeptic's group. For a long time scientists in the field stuck with some bad science and denied the findings that challenged a lot of the Clovis conclusions.

Perhaps that is what Fellow Traveler is trying to discuss.

[Dinwar]

That could be--no one is denying that scientists made errors in the past. I'm just not sure what the OP is saying. It's specific about data, but very vague on what we're supposed to take away from said data.

[Fellow Traveler]

Originally Posted by Dinwar

That could be--no one is denying that scientists made errors in the past. I'm just not sure what the OP is saying. It's specific about data, but very vague on what we're supposed to take away from said data.

Sorry for any confusion I might have caused. I'm new to this forum so I want to say History and pre-history are very intreresting subjects. The question of Pre Clovis is facinating and the most memorable book I read about it is: "The First Americans" by J.M. Adovasio and develops this question in some detail. He was the principal investigator of the Meadowcroft Rockshelter in SW PA. He has documented points in the vicinity of fire pits dated to 15000 years ago. The Mesa Verde Site of Tom Dillehay has likely pre clovis remains as well. Intriguing subject and seems wide open at the present. Check out the NOVA Website concerning this topic. pbs.org/wgbh/nova/ancient/explore-pre-clovis-sites.

[WildCat]

How long has the Arctic been inhabited by humans? It seems to me that once that happened moving into North America is an obvious next step. I don't see why the Bering land bridge during the last ice age was necessary, just nomadic fisherman/seal hunters in small boats working the ice floes will get to North America eventually.

IIRC Louis Leakey opined that humans likely made it to North America 50,000 years ago, I don't remember his reasoning. I don't know if it was that long ago, but I think it's 20,000 years ago at least.

[Dinwar]

"Peopling of the New World" (J. E. Ericson, R. E. Taylor, and R. Berger, eds.) argued that until 11,000 years ago the islands off of Alaska were covered in ice, making such island-hopping impossible. They also argue that it made human and animal crossing impossible, though I'm not convinced of that (humans, at least, could bring supplies with them, so could cross at least some ice). That's really the issue here: Could humans have lived on the ice? If not, they had to wait until it withdrew to migrate into North America (or get there before it started, in which case odds are good that all evidence is buried under glacial till or has been transported out to sea).

I'm not saying they're right, I'm just presenting their argument for consideration.

[Skeptic Ginger]

New Evidence Puts Man In North America 50,000 Years Ago

Quote:

Radiocarbon tests of carbonized plant remains where artifacts were unearthed last May along the Savannah River in Allendale County by University of South Carolina archaeologist Dr. Albert Goodyear indicate that the sediments containing these artifacts are at least 50,000 years old, meaning that humans inhabited North American long before the last ice age.

Genetic mapping will eventually sort out most of human migration history, and they've already made a lot of progress in the research.

[Dinwar]

Quote:

...indicate that the sediments containing these artifacts are at least 50,000 years old, meaning that humans inhabited North American long before the last ice age.

I haven't read the article yet, but my initial reaction is one word: krotovina. Just because the sediment is of a certain age doesn't necessarily mean that the artifacts are. I've seen examples of bits of bone dragged into animal burrows myself, and it's only thanks to a far better ichnologist than I that we knew what we were looking at.

Originally Posted by Skeptic Ginger

Genetic mapping will eventually sort out most of human migration history, and they've already made a lot of progress in the research.

Genetics has the power to give us a good working hypothesis, but it will still need to be vetted via standard archaeological field work.

[Skeptic Ginger]

Originally Posted by Dinwar

....

Genetics has the power to give us a good working hypothesis, but it will still need to be vetted via standard archaeological field work.

OM word, Dinwar, how old are you? Did you get out of college in the 60s or something?

It's the other way around, the genetics can definitively confirm or refute standard archeological findings.

Do you even know how the genetic trail is followed? It's accuracy and reliability have been confirmed multiple times through many different means.

As it turns out, the vast majority of both the path of human migration as determined by following the path of the evolution of language, and the path of human migration as determined by archeology evidence have been corroborated by the genetic trail. Only a few corrections were needed.

But where either archeology or language evolution evidence is not backed up with genetic evidence, it's the genetic evidence that is considered definitive.

There are times where genetic mixing after the migration event can confuse the evidence but genetic researchers have taken this into consideration. There are ways to work around this limitation.

You should take a good look around the Nat Geo human migration project web page. And I can find another couple of really good sources for you if you are interested.


As for the 50K yr old layers that human remains have been found in, obviously more than a single site is needed to confirm that finding. IIRC, there was a confirmed 25K yr old site in South America but the 50K article came up on my search so I didn't keep looking for it. I think there was also genetic evidence that people native to the Tierra del Fuego Archepeligo off the tip of So America had genetic evidence of being Polynesian and not evidence of having been part of the migration from Asia. Only two women who were still pure members of the tribe were left and they will be the last of their kind. I'll have to look for that evidence.

[Dinwar]

Originally Posted by Skeptic Ginger

OM word, Dinwar, how old are you? Did you get out of college in the 60s or something?

Nope. I'm a paleontologist, and therefore understand one limitation of genetics that no one ever seems to want to address: a genetic study of modern organisms can only tell you HOW THOSE MODERN ORGANISMS ARE RELATED TO EACH OTHER. It doesn't, and cannot, give you an accurate view of the evolutionary history of the group. Genetic studies in general are limited to the lifespan of DNA, which isn't terribly long (at least, DNA strands long enough to be at all useful don't survive for very long, geologically speaking [and we're talking Quaternary geology here, whether you like it or not]). Anything that didn't survive into the modern era is inherently invisible to genetic studies.

Then you have the issues of how you analyze your data. You pick the method you want to use and I'll show you how adding ancient data messes with it. Once you get into the math adding new groups to a cladogram gets extremely messy.

At best what genetic studies give you is a working hypothesis about some evolutoinary pathway, which then must be verified via field work. Again, certain things are invisible to this technique, but can play a critical role in the history of a population or organism. We need to fill in the gaps in order to say that anything is proven in any sense.

Quote:

It's the other way around, the genetics can definitively confirm or refute standard archeological findings.

No, it can't. If I find a village with logs radiocarbon dated to 15 ka, I don't care how much genetic data you have--the village is proof that humans were there at 15 ka. What genetic data CAN do is allow us to hypothesize that specific groups were there earlier than the FADs prove, or later than the LADs prove. But no amount of DNA can disprove archaeological evidence. If your DNA data says that humans weren't there, and I have physical evidence that they were, your DNA data is wrong, almost certainly because it is (as I discussed previously) incomplete.

Quote:

...it's the genetic evidence that is considered definitive.

Oh, I don't disagree that it's CONSIDERED definitive. Biologists love to consider their evolutionary trees built on modern DNA definitive as well. However, again, genetic data has inherent limitations, the most obvious being that you can only use this method to study organisms for which you have DNA. If you're talking a set of organisms for which you know no population has ever gone extinct (in some cases, link ring species or Hawaian fruit flies, this holds true), that may be fine. Or maybe your research question doesn't address the historical aspects of the group in question (such as "Do these fish share a recent common ancestor?"), in which case yeah, genetics will be more than sufficient. But as soon as you start talking about the history of organisms, particularly when populations may or may not have continued to present, genetic data is insufficient. I don't care if it's considered definitive; it's NOT, for sound scientific reasons.

Quote:

You should take a good look around the Nat Geo human migration project web page. And I can find another couple of really good sources for you if you are interested.

Skeptic Ginger, do you honestly think that in ten years of studying paleontology I haven't looked into what is considered by many to be the be-all, end-all of historic data? I'm not that bloody incompetant, and the references I looked into were far better than Nat Geo (peer reviewed publications back when I was having this discussion with an old-school paleontologist and a new-school biologist). But I ALSO looked into its limitations, not just its strengths. Yes, genetic data has limitations. Sorry, but it's not as simple as "Genetics says it, I believe it, that settles it." It's a powerful tool, but that's all it is--a tool, which yields a working hypothesis. And hypotheses are not facts.

You want to prove me wrong? I've stated specific concerns with genetic data. Either prove that those concerns are not present in this dataset (here's a tip: You've already admitted that human populations disapear, so you can't do this), or provide specific methods by which geneticists can get around those issues.

[Darth Rotor]

Dinwar, thanks for putting the E into JREF for me this morning. I had a gut feeling in my head about "but what about villages that go extinct, or social groups that die off or move off" and you were able to fill out the gaps in my understanding very well.

Appreciated.

[xterra]

The last time I talked to Adovasio (about 2004, I think), he said he was finding evidence of human activity at Meadowcroft at about 18,000 BP.

[Skeptic Ginger]

OK, well I didn't bother investing the time in arguing genetic evidence vs the 'standard' paleoanthropological science, but that doesn't mean I conceded the debate.

Here's an example from today's news that will make the discussion a little easier: Ancient migration: Genes link Australia with India

Quote:

Australia experienced a wave of migration from India about 4,000 years ago, a genetic study suggests.

It was thought the continent had been largely isolated after the first humans arrived about 40,000 years ago until the Europeans moved in in the 1800s.

But DNA from Aboriginal Australians revealed there had been some movement from India during this period.

The researchers believe the Indian migrants may have introduced the dingo to Australia.

In the Proceedings of the National Academy of Sciences, they say that the fossil record suggests the wild dogs arrived in Australia at around the same time.

They also suggest that Indians may have brought stone tools called microliths to their new home.

So, is the paleoanthropological evidence needed to confirm the genetic evidence or does the genetic evidence stand on its own merit? If one conflicted with the other, which of the two bodies of evidence would be more likely to be correct?

There were no current populations of Indians on the continent of Oz when the Europeans arrived. The genetic evidence even supports the timeframe of 4,000 years ago despite the fact they didn't sample 4,000 yr old genetic material to draw the conclusion.

Quote:

To study the early origins of Australia's population, the team compared genetic material from Aboriginal Australians with DNA from people in New Guinea, South East Asia and India.

By looking at specific locations, called genetic markers, within the DNA sequences, the researchers were able to track the genes to see who was most closely related to who.

They found an ancient genetic association between New Guineans and Australians, which dates to about 35,000 to 45,000 years ago. At that time, Australia and New Guinea were a single land mass, called Sahul, and this tallies with the period when the first humans arrived.

[Skeptic Ginger]

Here's the original source: Genome-wide data substantiate Holocene gene flow from India to Australia

Quote:

The Australian continent holds some of the earliest archaeological evidence for the expansion of modern humans out of Africa, with initial occupation at least 40,000 y ago. It is commonly assumed that Australia remained largely isolated following initial colonization, but the genetic history of Australians has not been explored in detail to address this issue. Here, we analyze large-scale genotyping data from aboriginal Australians, New Guineans, island Southeast Asians and Indians. We find an ancient association between Australia, New Guinea, and the Mamanwa (a Negrito group from the Philippines), with divergence times for these groups estimated at 36,000 y ago, and supporting the view that these populations represent the descendants of an early “southern route” migration out of Africa, whereas other populations in the region arrived later by a separate dispersal. We also detect a signal indicative of substantial gene flow between the Indian populations and Australia well before European contact, contrary to the prevailing view that there was no contact between Australia and the rest of the world. We estimate this gene flow to have occurred during the Holocene, 4,230 y ago. This is also approximately when changes in tool technology, food processing, and the dingo appear in the Australian archaeological record, suggesting that these may be related to the migration from India.

[Dinwar]

Originally Posted by Skeptic Ginger

So, is the paleoanthropological evidence needed to confirm the genetic evidence or does the genetic evidence stand on its own merit?

Let me translate this question for you: Is a single line of indirect evidence sufficient to establish a hypothesis as true? In my opinion no, so the answer to your question as you worded it is yes (if that makes sense). At minimum, it's certainly a very, very good idea to look for the evidence.

Do you think genetic hypotheses are infalliable? If not, then we need to confirm them. If you do, I'd love to see how you get around the issues that I raised earlier.

Originally Posted by Skeptic Ginger

If one conflicted with the other, which of the two bodies of evidence would be more likely to be correct?

I have already answered that question. The answer is that this is begging a number of questions and ignoring the realities involved in archaeological and paleontological analyses.

Originally Posted by Dinwar

What genetic data CAN do is allow us to hypothesize that specific groups were there earlier than the FADs prove, or later than the LADs prove. But no amount of DNA can disprove archaeological evidence. If your DNA data says that humans weren't there, and I have physical evidence that they were, your DNA data is wrong, almost certainly because it is (as I discussed previously) incomplete.

Originally Posted by Skeptic Ginger

There were no current populations of Indians on the continent of Oz when the Europeans arrived. The genetic evidence even supports the timeframe of 4,000 years ago despite the fact I don't believe they sampled 4,000 yr old genetic material to draw the conclusion.

Right--what they almost certainly did was to sample modern Indian DNA, and modern Australian DNA (Aboriginal Australians, obviously). They found similar genes between the two groups--likely genes that are assumed to have arisen in India and brought to Australia via migration. Then they looked at molecular clocks within those genes to determine the age of the migration. That's how this stuff is normally done.

You'll note that, as I said before, a population that didn't survive into the modern era would be completley invisible to this sort of analysis. We can conclude, if you're willing to accept a single line of reasoning, that the genes ultimately came from India (I'm not saying it's right, wrong, or indifferent to do this, just that that's what you're doing). We CANNOT conclude ANYTHING about what happened to that population on the way there. We can tenatively conclude the timeframe (I'm not a fan of molecular clocks; I think that the assumption of constant rates of genetic change hasn't been tested adequately, but I'm willing to accept the results tentativley, in the absence of more rigorous data), but we CANNOT conclude ANYTHING about what happened during that timeframe. We can conclude that the genes left India at that time, but we can't conclude that they got to Africa at that time. Molecular clocks work via population isolation--they accumulate different mutations (presmumably at a constant rate). Unless we had a sample of the population that no longer exists, we can't be certainly they went from India immediately to Australia. If we DO have DNA from those populations, we obviously also have other evidence--you get DNA from chunks of the critter, such as hair, teeth, bone, or skin, after all.

As an aside, the quote you presented provides numerous areas which should be researched via good old-fashioned field work, including examination of dingos vs. Indian canines, comparisons between stone tools, etc. I'd say boats would also be a nice way to really seal this argument (if we find a boat from that time period [and by "boat" I mean "anything that'll get you to Australia"] we can conclude that SOMEONE came there, and the DNA evidence gives us good evidence of who). DNA isn't the whole story, not by a very, VERY long shot, and the people you're quoting are admitting it in what you're quoting. The only difference between them and me is where we place our emphasis, not our general conclusions.

[WildCat]

And the dingo has been menacing babies in Australia ever since.

[Dinwar]

I want to emphasize that I am in no way saying that genetic evidence is bad. Far from it--it's an extremely powerful tool, one that can answer many questions we couldn't even ask even thirty years ago. I'm merely saying that a disproportionate amount of emphasis has been placed on genetic evidence recently, and that the limits of genetic evidence are not sufficiently noted or addressed many times. Providing evidence that extends our knowledge beyond a FAD or LAD is a tremendous achievement, something that was inconcievable prior to genetic evidence--but we can easily misinterpret genetic data, the same as we can misinterpret any other data, and therefore the conclusions from genetic evidence need to be treated the same as those reached by any other line of reasoning in historic sciences.

[Skeptic Ginger]

Originally Posted by Dinwar

Let me translate this question for you: Is a single line of indirect evidence sufficient to establish a hypothesis as true?

Yes, once you confirm the methodology, like radio isotope dating methods for example. It is considered definitive for dating rock layers, is it not?

I'll get to the rest later. The dogs are whining to go on their walk.

[Dinwar]

Originally Posted by Skeptic Ginger

like radio isotope dating methods for example. It is considered definitive for dating rock layers, is it not?

You're joking, right? I don't know anyone who'd say "The radio isotopes say it's X years old. Well, that's good enough for me! Let's move on!" There are way, way, WAY too many complicating factors. I know that C14 dating of sediment is frequently done in conjunction with optically stimulated luminescence studies, for exactly that reason.

And radio isotopic studies are never done in a vacuum. They are always done in conjunction with detailed stratigraphic work. For the stuff where it's possible, they're often done in conjunction with paleontological work. The reason is, weird things can happen--I once got ahold of some data from south of the Salton Sea that was contaminated by "dead" carbon, for example. If you just went by the one line of evidence you'd think that the bed was a few thousand years older than the same stratigraphic layer a few miles away. Besides, how do you think they figure out what isotopic family to use? Ideally you use isotopes that have undergone one to three or four half-lives in order to date rocks--too few or too many and the signal to noise ratio starts shifting to the noise side too much. They don't pick the isotopic families randomly--they use past studies, often stratigraphic studies conducted before radiometric dating was available, to determine what isotopic families to use, so alternate lines of evidence are built into the study. So it's not analogous to genetic hypotheses, which are frequently done via DNA alone.

And that's just the basics. That's not getting into issues like volcanics with multiple episodes of intrusion and deformation, or regions that have undergone repeated extensiona/compressional tectonic activity, or the whole issue of sedimentary rocks (you can only radiometrically date igneous, and to a lesser extent metamorphic, rocks--sandstlone, limestone, shale, and other sedimentary rocks are undatable via that method). You can take all the radiometric dating samples you want from the Chatsworth Formation, and all that's going to happen is that you'll waste your money and the rest of us will have a good laugh. Then I'll go find a shell hash bed and date it to within a few hundred thousand years. (Actually I won't--I'll get down my book on the topic, because that study has already been done.)

There is no line of evidence that can be applied uncritically. Science is not some cookie-cutter procedure--particularly not historical sciences, where we have to deal with all sorts of confounding factors, including everthing from natural contamination to random chance. So no, radiometric dating alone is not considered conclusive. It's considered a powerful line of evidence, but in all cases other lines of evidence are considered.

[Skeptic Ginger]

Originally Posted by Dinwar

You're joking, right? I don't know anyone who'd say "The radio isotopes say it's X years old. Well, that's good enough for me! Let's move on!" There are way, way, WAY too many complicating factors. I know that C14 dating of sediment is frequently done in conjunction with optically stimulated luminescence studies, for exactly that reason.

So we don't end up here arguing past each other here, I'm not talking about range error or that a single sample is definitive. And as for optically stimulated luminescence studies, you are merely talking about a closely related dating technique. That's like saying we used two different tools and got similar measurement. It's not like saying paleoanthropological evidence was combined with measurements using scientific instrument techniques to confirm the date.

I'm pretty sure I see genetic evidence as more 'hard' data than you do.

Again, my apologies for not addressing all your points. I don't want to do that until we clarify what it is we are disagreeing about here.

[Dinwar]

Originally Posted by Skeptic Ginger

So we don't end up here arguing past each other here, I'm not talking about range error or that a single sample is definitive.

Neither am I. The Sultan Sea thing is a issue known to most SoCal sedimentologists/paleontologists [ETA: I should emphasize, the issue there isn't unique--it's something that can happen in any volcanic environment, and in a lot of others as well]. There are other issues I raised that are systematic, meaning all radiometric dating has them. That's not getting into the biases every method has--for example, C14 dating has what's affectionately known as "the Marine Bias", and uranium-series dating goes through a radon phase where you can lose a lot of radioactive material fairly quickly. Half of my book on isotopic geochem consists of "And this is ANOTHER way you can screw up interpreting this data".

Quote:

And as for optically stimulated luminescence studies, you are merely talking about a closely related dating technique.

No, they're not--they are two very different techniques, which is why they're such a good combination. C14 dating uses a cosmogenic nucleotide that's taken up by organisms (mostly plants) and therefore records the time of death of the organism. Optically stimulated luminescence relies on the fact that background radiation causes minor defects in quartz crystals that are reset via exposure to direct light. They are two completely different dating techniques, relying on completely different processes (with the obvious caveat that C14 decay will contribute to the background radiation, obviously). If they weren't, they couldn't be used to check each other--biases in one would be transmitted to the other.

Quote:

It's not like saying paleoanthropological evidence was combined with measurements using scientific instrument techniques to confirm the date.

I fail to see why the two situations aren't analogous [ETA: What i mean is, using multiple lines of evidence to support a conclusion is the analogous part--obviously, radiometric dating in general has some serious failures as an analogy with genetic analysis]. I'll grant you that they're different, sure, but it's an analogy; they're all flawed.

Besides, you brought radiometric dating up. If it were me, I'd go with remote sensing. Satellite images can get you extremely good data. Unfortunately, in order to know what that data means you need to do a process called "ground truthing", which basically consists of going out and making sure you're seeing what you think you're actually seeing. The data can be ambiguous--for example, in a desert I once saw sat images showing high-albedo areas (basically really highly reflective; they look white in the sat photos). In some areas this is due to the presence of tuffas. Fortunately, we ground truthed the data--some of the other areas had high albedo due to the presence of gypsum. And sat photos can only show you the surface features. Anything buried under anything (gravel, sand, snow, leaves....) is invisible (well, it's more complicated than that, but you can only ever go to very, very shallow depths). Genetic data is like that: it gives you good data, and you can formulate very interesting hypotheses from it, but those hypotheses need to be ground truthed. You know that there was an influx of Asian DNA into Australia sometime after 4ka. Until you find some other evidence you can't say conclusively that 4ka is when they arrived--only that that's when they left. That's analogous to me going into the desert to figure out what the white spots on the map were.

Quote:

I'm pretty sure I see genetic evidence as more 'hard' data than you do.

To be clear, it's not the data that I question. The data, in any situation, are what they are. It's the interpretations that I don't find as convincing as you do. The same data can support numerous interpretations, particularly when the data has biases as substantial as those I've outlined for genetic data.

[Fellow Traveler]

I'm just a very interested layman re archeaology and antropology but still I as most of the public must sift thru conflicting expert opinions. Likely, if you got a room full of pros they would argue until blue in the face. My layman's view is formed from 40 years of reading journals like Smithsonian and Science etc. My own impression is that it makes no sense for the appearance of man to cause the sudden die off of the American beasts such as Mastadons, Mammouths, Sabre toothed tiger giant ground sloth and huge bison et al. If people came here just a few 1000 years before the die off, they would have been scattered and very few in one location. The beauty of this field is that new discoveries will never stop. Last night I saw for the 2d time a show on PBS about the big die off of the mammals mentioned above, somewhere in Colorado in an ancient lake bed. Some exceedingly interresting finds were made; Mastadons/Mammoths bones covered by random (sort of random) boulders which the investigators took as possible cacheing of the meat from wild animals. Also they found a large bone with parallel scratch incisions, which could also indicate men there. The catch is this seems to be a 100,000 year old site. Archeaology is the Star Trek of Diciplines "Going where no man has gone before"

[Skeptic Ginger]

Here's the link for you, FT: NOVA - ICE AGE DEATH TRAP. You can watch the program free online, or just read the transcript.

[Dinwar]

The Overkill Hypothesis (as the idea that humans killed off the Pleistocene megafauna is known) is a bit more complex than "We killed 'em all". The actual killing of large predators is a fairly minor part of it, in fact. What we did was, we became a new competator for food resources--we ate the same food as dire wolves, saber-toothed cats, and whatnot. people have the wrong view of competition; most of the time, when two organisms compete for food one will simply find another food source. Happens with birds, happens with barnacles, and it happens with predators. When we came into the ecosystem we easly out-competed dire wolves and the rest, forcing them to move to less-favorable foods. Eventually, there was no niche left for them.

This is also an explanation for why orkas eat sea lions now. They would prefer to eat whales, but there's not enough whale to feed them anymore thanks to human competition. So they moved to less-appealing whales, and eventually to non-whales.

It's hard to say how many humans it would take to cause this, which is why there's so much debate. Pleistocene ecosystems were much more top-heavy than any today, meaning that there were far more predators per prey unit than even the "untouched" ecosystems today (in scare quotes because the loss of predators suggests strongly that they are NOT untouched). Predators were at the upper edge of their carrying capacity; it may not have taken much in the way of additional competition to drive the ecosystem to the point where extinctions were happening.

[Skeptic Ginger]

Originally Posted by Dinwar

T...The actual killing of large predators is a fairly minor part of it, ...

You can't know that. It's my understanding there's no consensus yet.

[Dinwar]

Originally Posted by Skeptic Ginger

You can't know that. It's my understanding there's no consensus yet.

That would be why I mentioned a specific model for the extinction of the Pleistocene megafauna. The Overkill Hypothesis is one of several currently being kicked around. The reason I went into detail is because it was the hypothesis being discussed, and the discussion missed a few key aspects of it.

And I CAN know it. It's my JOB to know it, if I'm able--at the very least, my job is to find evidence one way or another. That's sort of the focus of Quaternary paleontology. Others may not agree with my conclusions, but as long as I can support my conclusion with valid data I can reasonably and intellectually honestly hold it. Consensus is only a useful rule of thumb, and even then is limited to people with little knowledge about the field. Someone like me, who's spent the past years in the field (and longer in a related one), is expected to be a tad more rigorous about their conclusions--we're expected to follow the data, regardless of the consensus. To a paleontologist the consensus in paleontology is expected to be irrelevant (in practice, the consensus is often criticized by many people, even those who agree with it; we like to argue).

I'll grant you that I'm not convinced the Overkill Hypothesis is right; I'm sort of leaning that way, given the data I've seen, but there are serious flaws with it (for example, why didn't the people domesticate any of the animals?). I'm merely arguing that you are wrong that someone in the field needs to wait for a consensus to draw a conclusion. If you were right, there'd be no way to HAVE a conclusion--we'd all have to wait for a consensus before we could say we know anything, and since no one could speak up there'd never be a consensus.

[Skeptic Ginger]

Originally Posted by Dinwar

That would be why I mentioned a specific model for the extinction of the Pleistocene megafauna. The Overkill Hypothesis is one of several currently being kicked around. The reason I went into detail is because it was the hypothesis being discussed, and the discussion missed a few key aspects of it.

And I CAN know it. It's my JOB to know it, if I'm able--at the very least, my job is to find evidence one way or another. That's sort of the focus of Quaternary paleontology. Others may not agree with my conclusions, but as long as I can support my conclusion with valid data I can reasonably and intellectually honestly hold it. Consensus is only a useful rule of thumb, and even then is limited to people with little knowledge about the field. Someone like me, who's spent the past years in the field (and longer in a related one), is expected to be a tad more rigorous about their conclusions--we're expected to follow the data, regardless of the consensus. To a paleontologist the consensus in paleontology is expected to be irrelevant (in practice, the consensus is often criticized by many people, even those who agree with it; we like to argue).

I'll grant you that I'm not convinced the Overkill Hypothesis is right; I'm sort of leaning that way, given the data I've seen, but there are serious flaws with it (for example, why didn't the people domesticate any of the animals?). I'm merely arguing that you are wrong that someone in the field needs to wait for a consensus to draw a conclusion. If you were right, there'd be no way to HAVE a conclusion--we'd all have to wait for a consensus before we could say we know anything, and since no one could speak up there'd never be a consensus.

You said, "The actual killing of large predators is a fairly minor part of it".

Either it is or it might be or it's likely or unlikely or currently believed, whatever!

Make up your mind.


You could even say the evidence overwhelmingly supports, if it did and if you could show that. I don't think you can.

[Dinwar]

Quote:

You said, "The actual killing of large predators is a fairly minor part of it".

What you did here is called pulling a quote out of context. Here's the full context:

Originally Posted by Dinwar

The Overkill Hypothesis (as the idea that humans killed off the Pleistocene megafauna is known) is a bit more complex than "We killed 'em all". The actual killing of large predators is a fairly minor part of it, in fact.

To any standard English speaker, it's obvious that the "it" I was referring to was the Overkill Hypothesis--a topic that was being danced around prior to my post. So I CAN say that the Overkill hypothesis is likely to be true and that actually killing off large numbers of predators is a fairly minor part of it, without any contradiction.

Killing off predators IS only a minor part of the Overkill Hypothesis. The OH MIGHT be true. If you can't see how that works, well, that's your problem. It's plain English and cannot be stated any more clearly.

Quote:

You could even say the evidence overwhelmingly supports, if it did and if you could show that. I don't think you can.

Considering the fact that you avoid conversations when I demonstrate a solid working knowledge of the system in question, I really don't care what you think I can do. Your thoughts in regards to my level of knowledge aren't based on the facts. (And don't say it didn't happen--it's happened in this thread.) I doubt I could convince you of anything, even if every datum supported my position, so I won't bother trying.

[Skeptic Ginger]

Originally Posted by Dinwar

What you did here is called pulling a quote out of context. Here's the full context:

To any standard English speaker, it's obvious that the "it" I was referring to was the Overkill Hypothesis--a topic that was being danced around prior to my post. So I CAN say that the Overkill hypothesis is likely to be true and that actually killing off large numbers of predators is a fairly minor part of it, without any contradiction.

Killing off predators IS only a minor part of the Overkill Hypothesis. The OH MIGHT be true. If you can't see how that works, well, that's your problem. It's plain English and cannot be stated any more clearly.

Considering the fact that you avoid conversations when I demonstrate a solid working knowledge of the system in question, I really don't care what you think I can do. Your thoughts in regards to my level of knowledge aren't based on the facts. (And don't say it didn't happen--it's happened in this thread.) I doubt I could convince you of anything, even if every datum supported my position, so I won't bother trying.

Come on Dinwar, "is a fairly minor part" means just that. There was no out of context distortion. Yeah, I get it you talked about the rest.

There is no consensus what percentages the total impact of humans overhunting played (it's not like we don't have plenty of examples in modern times) vs habitat destruction vs disease introduction vs another asteroid impact or volcanic impact on climate or other impact.

Over hunting could be major or minor you said IS MINOR.

If you can't admit to misspeaking, or if you insist on arguing the definition of "is" , then no, we can't have much of a discussion.

[Dinwar]

Originally Posted by Skeptic Ginger

Come on Dinwar, "is a fairly minor part" means just that.

A fairly minor part OF WHAT? I can confidently say that it's a fairly minor part of the overkill hypothesis, for the very good reason that one of the people who is pushing that hypothesis told me so. You want to argue with that, take it up with her.

Quote:

There is no consensus what percentages the total impact of humans overhunting played (it's not like we don't have plenty of examples in modern times) vs habitat destruction vs disease introduction vs another asteroid impact or volcanic impact on climate or other impact.

Again, the consensus is irrelevant. I've talked to experts, and have studied the data, so that shortcut is irrelevant to me. Secondly, I WAS NOT TALKING ABOUT THE MASS EXTINCTION, ONLY THE OVERKILL HYPOTHESIS. Is that clear enough? Sorry for the font manipulation, but you don't seem able to read this statement in ordinary text.

Quote:

Over hunting could be major or minor you said IS MINOR.

No. I said that IN THE OVERKILL HYPOTHESIS it was a minor factor.

Quote:

If you can't admit to misspeaking, or if you insist on arguing the definition of "is" , then no, we can't have much of a discussion.

If you insist on defending an obviously cherry-picked quote, ripped from the context, you're going back on my "Ignore" list. To any rational English speaker it's obvious that I was talking about the Overkill Hypothesis when I said the quote that got your dander up. If you're going to be so irrational as to refuse to understand the language, and to refuse to accept a perfectly valid explanation, there's no sense in talking to you.

When I said that killing predators was a minor part, I specifically was referring to it being a minor component in a particular hypothesis. Are you willing to accept that and move forward in this conversation?

[Skeptic Ginger]

You are going nowhere Dinwar except falsely believing that I don't really disagree with you, just misunderstood what you said.

I read it, I did not misread it. There is no consensus that hunting was or was not a minor part of the extinction event. Yes, habitat destruction and/or food competition could have been the major mechanisms, OR NOT.

I happen to think it is more plausible a small population of humans would have hunted the large mammals to extinction much more easily than a small population of humans would have occupied the habitat and ate all the large mammal food sources. It's not like large corporate farming and the construction of cities was going on in N America at the time.

Wiki on the extinction event.

Quote:

Another factor contributing to their eventual extinction in America during the late Pleistocene may have been the presence of Paleo-Indians, who entered the American continent and expanded to relatively large numbers 13,000 years ago.[21] Their hunting caused a gradual attrition of the mastodon and mammoth populations, significant enough that over time the mastodons may have been hunted to extinction.[22][23] Analysis of tusks of mastodons from the American Great Lakes region over a span of several thousand years prior to their extinction in the area shows a trend of declining age at maturation; this is contrary to what one would expect if they were experiencing stresses from an unfavorable environment, but is consistent with a reduction in intraspecific competition that would result from a population being reduced by human hunting.[23]

I don't claim to know, but I do say there is not a consensus that is consistent with your post.

[Dinwar]

Originally Posted by Skeptic Ginger

There is no consensus that hunting was or was not a minor part of the extinction event.

Originally Posted by Dinwar

I WAS NOT TALKING ABOUT THE MASS EXTINCTION, ONLY THE OVERKILL HYPOTHESIS

Originally Posted by Dinwar

And I CAN know it. It's my JOB to know it, if I'm able--at the very least, my job is to find evidence one way or another. That's sort of the focus of Quaternary paleontology. Others may not agree with my conclusions, but as long as I can support my conclusion with valid data I can reasonably and intellectually honestly hold it. Consensus is only a useful rule of thumb, and even then is limited to people with little knowledge about the field. Someone like me, who's spent the past years in the field (and longer in a related one), is expected to be a tad more rigorous about their conclusions--we're expected to follow the data, regardless of the consensus. To a paleontologist the consensus in paleontology is expected to be irrelevant (in practice, the consensus is often criticized by many people, even those who agree with it; we like to argue).

And with that, folks, we're done.

You're obviously not paying any attention to what I'm writing, SG. I can put up with you arrogantly asserting simply erroneous ideas; that, at least, we can discuss. But you insist on making this a one-way conversation, so there's no point to me participating.

[Skeptic Ginger]

Originally Posted by Dinwar

And with that, folks, we're done.

You're obviously not paying any attention to what I'm writing, SG.

Yes yes, the infamous, if you disagree with me it's because you don't understand what I said.

Originally Posted by Dinwar

I can put up with you arrogantly asserting simply erroneous ideas;

Care to address the sources I cited? The Wiki sources, not Wiki.

Quote:

^ Beck, Roger B.; Linda Black, Larry S. Krieger, Phillip C. Naylor, Dahia Ibo Shabaka, (1999). World History: Patterns of Interaction. Evanston, IL: McDougal Littell. ISBN 0-395-87274-X.
^ Ward, Peter (1997). The Call of Distant Mammoths. Springer. pp. 241. ISBN 978-0-387-98572-5.
^ a b Fisher, Daniel C. (2009). "Paleobiology and Extinction of Proboscideans in the Great Lakes Region of North America". In Haynes, Gary. American Megafaunal Extinctions at the End of the Pleistocene. Springer. pp. 55–75. doi:10.1007/978-1-4020-8793-6_4. ISBN 978-1-4020-8792-9.

Perhaps you'd like to show the conclusions in the Wiki source are not supported by these citations. Peter Ward is a U of WA professor and I've been to a couple of his lectures. His work is legit.

Originally Posted by Dinwar

that, at least, we can discuss. But you insist on making this a one-way conversation, so there's no point to me participating.

Did you or did you not say that hunting, specifically men killing beasts directly, was a minor contributor to the mastodon die off?

Did I not say, with supporting citations now, that this is not a scientific consensus? Some scientists believe that hunting, as in direct killing, played a major role in the die off.

Have you or have you not asserted that you are right? Your opinion and expertise in the field aside, is there a scientific consensus that direct hunting played a minor role?

No one is taking your comments out of context.

Originally Posted by Dinwar

I can support my conclusion with valid data I can reasonably and intellectually honestly hold it.

You can, but you cannot say it is a fact when the scientific consensus is that the answer is still uncertain. You can say, it's your personal opinion. That is not what you did say, you wrote a claim as a statement of fact. The supporting data may be convincing in your opinion. But not being the opinion of your peers is a bit of a drawback for you.


*PS Sorry for all the edits, I'm done now.

[Fellow Traveler]

Couple things on my mind about this subject: Since the American Continent had the large mega fauna that was killed off by some means, is there evidence that some ancestor of the Mammouth or Mastadon migrated to America or is there some separate evolution? Do these animals predate the splitting of the continents? Excuse me if that's a dumb question but I wonder.
Second: Maybe there ought to be a high school level book on the overall subject of the peopling which might go along the lines of " Scientists argue over the way people came to America but most believe......And get the younger generation excited over the intrigue.

[Delvo]

Originally Posted by Fellow Traveler

Since the American Continent had the large mega fauna that was killed off by some means, is there evidence that some ancestor of the Mammouth or Mastadon migrated to America or is there some separate evolution?

The mammoth/mastodon/elephant lineage originated in the Old World and spread to the New World millions of years ago. The Bering Strait has been open to land migrations more than once in that time. Some animal lineages, including not only mammoths but also brown/grizzly bears and gray wolves and horses and camels, are known for existing on both sides. Mammoth bones & mummies hardly distinguishable from North American ones have been found in Siberia. Eurasia also has more variety of other fossils of pachyderm/elephantid/proboscid relatives like Dinotherium.

Originally Posted by Fellow Traveler

Do these animals predate the splitting of the continents?

No. That process happened in stages between 100 and 200 million years ago, and most mammal diversification happened less than 65 million years ago. When North & South America first separated from Eurasia and Africa, they didn't even have placental mammals at all yet, just marsupials (and maybe monotremes and/or something else that's now extinct). North America would later import placentals during one or more separate times that it had land bridges with Siberia to the west or with Greenland and northern Europe to the east. South America got them still later by way of Panama.

Originally Posted by Fellow Traveler

Maybe there ought to be a high school level book on the overall subject of the peopling which might go along the lines of " Scientists argue over the way people came to America but most believe......And get the younger generation excited over the intrigue.

I presume there are such books, but don't know. But there have been documentaries like this one by BBC, which is a part of a series of documentaries covering human prehistory in several different regions of the world. It starts covering doubts about Clovis-first theory at about 18 minutes and makes its case for an alternative beginning at about 41.

[Dinwar]

Originally Posted by Fellow Traveler

Maybe there ought to be a high school level book on the overall subject of the peopling which might go along the lines of " Scientists argue over the way people came to America but most believe......And get the younger generation excited over the intrigue.

The Illustrated Encyclopedia of the Prehistoric World is a good place to start. It's got mammals and dinosaurs more or less organized taxonomically, but doesn't go into brain-breaking detail. A bit dated, perhaps, but it's a textbook; what can you do?

Originally Posted by Delvo

The mammoth/mastodon/elephant lineage originated in the Old World and spread to the New World millions of years ago.

Interesting, and thank you. I've never had a chance to look at mammoth migration. I do like the fact that a lot of lineages that started here went extinct in North America--horses and camels, if I recall correctly, originated in North America but were completely gone by the time Europeans showed up. Leads to an interesting question: If a group is wiped out on a continent, then a member of that group is re-introduced before the ecosystem has a chance to adapt to its loss, does it count as an invasive species?

[Soapy Sam]

America is a big place.
If we want to write SF, there are many good tales to tell of the (anywhere from ten to two thousand) palaeo-ninjas who got there first, but did they play a significant part in the future of H sap in the noo world?
The thing about evidence of a culture is...it implies the existence of a culture. (Whereas a fireplace dated 20,000BP indicates the presence of... a fireplace! )

Were there people in America before 18,000? Maybe. Possibly even probably. But not a lot. There have been people on the moon, which implies a culture...not on the Moon, but somewhere in the neighbourhood.

But you know what spooks me? What was a Merovingian doing over there in the first place? Makes you wonder...