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Author | Topic: New Type of Ancient Human Found—Descendants Live Today? | |||||||||||||||||||||||||||||||||||||||||||||||
Blue Jay Member (Idle past 2728 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Hi, Jon.
Jon writes: By that definition, would anyone who possesses ample African-originated genetic material would qualify as African? Yes. -----
Jon writes: Everything we know about the way people live, grow up, leave the nest, and start their own families suggests that the first exodus (of erectus) was of a slow, expansion-like typeurban sprawl in a hunter-gatherer fashion. How do you gather this? My ancestors and yours came from across a frickin' ocean, for crying out loud! Everything we know about the way people live, grow up, leave the nest, and start their own families suggests that people may go pretty much any-damn-where after "leaving the nest." Nomads doubly so. -----
Jon writes: A pattern of on-off isolation is not inconsistent with MH. But it is inconsistent with your model of no migration. -----
Jon writes: You're still only addressing the movement of genetic material. I'm addressing the movement of a whole frickin' lot of genetic material over a long distance, and the concomitant disappearance of virtually all other genetic material. You don't get that by having everybody stay where they have always stayed and allowing some gametes to percolate through hybrid populations. You get that by having somebody uproot and invade. This is how North America came to be populated by Native Americans in the first place, and how its gene pool later came to be dominated by white people from Europe. A few pockets of Native American genome survive.A very few pockets of Denisovan and Neanderthal genome survive. Most of North America's population is from Old World sources. Almost all of Eurasia' population is from Paleolithic African sources. Do you see the parallels? Why do these parallels not point to similar causative events?
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Jon Inactive Member |
How do you gather this? My ancestors and yours came from across a frickin' ocean, for crying out loud! You cannot really make such comparisons across water boundaries; humans cannot live on water. The movements of people from Europe to the Americas does show some 'rush' characteristics, but it is otherwise just a simple spreading out of folk, albeit taking advantage of new technologies to spread out to previously inaccessible places. Either way, such things are rarities in the course of day-to-day living.
But it is inconsistent with your model of no migration. In what way? Perhaps you should clarify what you mean with 'migration'. It is clear that this term is getting us all a little caught up. Certainly folk moved about; the issue is how much they moved. What level of movement qualifies as 'migration' in your book? The type of movement I envision doesn't cut it in my book.
You don't get that by having everybody stay where they have always stayed and allowing some gametes to percolate through hybrid populations. You get that by having somebody uproot and invade. Again, you keep saying this, but still do not offer evidence to support it.
This is how North America came to be populated by Native Americans in the first place, and how its gene pool later came to be dominated by white people from Europe. Again, this is one way for moving genes. It is not the only way. Without further evidence, we should not assume anything beyond genetic flow. What evidence is there for the supposed super exodus of sapiens from Africa?
Do you see the parallels? Why do these parallels not point to similar causative events? Yes; we know that if people migrate, their genes migrate with them. However, what allows us to assume the reverse relationwhen genes migrate, people migrating must be behind it? This is the question of the hour! Jon Check out No webpage found at provided URL: Apollo's Temple! Ignorance is temporary; you should be able to overcome it. - nwr
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Blue Jay Member (Idle past 2728 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Hi, Jon.
Jon writes: Perhaps you should clarify what you mean with 'migration'. It doesn't really have that specific a meaning: directional movements, cyclical movements, movements of whole populations, etc., are all included. Any movement that results in an entity (individual, population, colony, haplotype, etc.) inhabiting an area that it didn't previously inhabit is properly called a "migration." -----
Jon writes: The movements of people from Europe to the Americas does show some 'rush' characteristics, but it is otherwise just a simple spreading out of folk... "'Rush' characteristics"? Who said anything about "rushing"? What does the speed of movement have to do with anything? Can migrations not be slow? Do you define "migration" by speed? OOA proponents, and evolution biologists in general, don't. Okay. Let's forget the colonization of America. Let's instead focus on the westward expansion of the Europeans and their derivative peoples (that's us) after we arrived in North America. We started in the east, then slowly "spread out" westward into new areas, displacing or killing the natives. Some of us tolerated and even intermarried with the natives, but they were mostly just swamped out or pushed aside. In the end, we have a gene pool that's almost entirely immigrant, with only a few pockets of native populations remaining. We also see the same thing happening with the European colonization of Australia and the Bantu expansion across sub-Saharan Africa. Aside from the technological differences, do you have any reason to think that the migration event proposed by OOA is any different from these? Call it "spreading out," if you want. But, it's still the same thing that OOA proposes. -----
Jon writes: Bluejay writes: This is how North America came to be populated by Native Americans in the first place, and how its gene pool later came to be dominated by white people from Europe. Again, this is one way for moving genes. It is not the only way. But, it is the only way that has been documented to effect the wholesale takeover of gene pools by genomes from other populations, so we should be in the habit of assuming it until something else comes along. -----
Jon writes:
This isn't how Ockham's razor works. Yes, it favors the "simplest" explanation, but "simplest" isn't chosen based only on the evidence you have in your hands: it's chosen by the context provided by the entire scientific literature. So, when two models are possible (e.g., hybridization with migration vs. migration with or without hybridization), you pick the one that has been successful in explaining other similar situations. Without further evidence, we should not assume anything beyond genetic flow. The evidence we have from population ecology and population genetics with a variety of species tells us that migration often results in the wholesale takeover of gene pools by immigrant populations and species. In contrast, as far as I'm aware, there are no documented cases of hybridization without migration causing the same result, so there is no precedent for it. And, a hypothesis without precedent doesn't earn the favor of Ockham's razor, regardless of how simple it seems to be. This means that Ockham's razor favors a migration model over a hybridization model. -Bluejay (a.k.a. Mantis, Thylacosmilus) Darwin loves you.
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Jon Inactive Member |
Okay. Let's forget the colonization of America. Let's instead focus on the westward expansion of the Europeans and their derivative peoples (that's us) after we arrived in North America. We started in the east, then slowly "spread out" westward into new areas, displacing or killing the natives. Some of us tolerated and even intermarried with the natives, but they were mostly just swamped out or pushed aside. In the end, we have a gene pool that's almost entirely immigrant, with only a few pockets of native populations remaining. We also see the same thing happening with the European colonization of Australia and the Bantu expansion across sub-Saharan Africa. Aside from the technological differences, do you have any reason to think that the migration event proposed by OOA is any different from these? I would say OOA proposes a very similar phenomenon. Interestingly, such events leave specific types of evidence; none of such evidence has been found, as far as I am aware, regarding sapiens and pre-sapiens.
But, it is the only way that has been documented to effect the wholesale takeover of gene pools by genomes from other populations, so we should be in the habit of assuming it until something else comes along. But our population boundaries aren't real; they're arbitrary. We don't actually have distinct and separate populations; we have just one. And we don't need massive migrations to move genes around within single populations.
In contrast, as far as I'm aware, there are no documented cases of hybridization without migration causing the same result, so there is no precedent for it. And, a hypothesis without precedent doesn't earn the favor of Ockham's razor, regardless of how simple it seems to be. What happens in any population of interbreeding individuals? Do they evolve on a whole as a population, or does every evolutionary innovation require a massive migratory takeover by the members carrying the novel genes?
It doesn't really have that specific a meaning: directional movements, cyclical movements, movements of whole populations, etc., are all included. Any movement that results in an entity (individual, population, colony, haplotype, etc.) inhabiting an area that it didn't previously inhabit is properly called a "migration." Only some of these are the type of specific movements proposed by OOA, though. Certain of them are perfectly compatible with MH, along with being expected behaviors of early humans. Jon Check out No webpage found at provided URL: Apollo's Temple! Ignorance is temporary; you should be able to overcome it. - nwr
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jar Member (Idle past 425 days) Posts: 34026 From: Texas!! Joined: |
But our population boundaries aren't real; they're arbitrary. We don't actually have distinct and separate populations; we have just one. And we don't need massive migrations to move genes around within single populations. Huh? We are talking about relatively small populations spread over very large geographical distances. Anyone so limited that they can only spell a word one way is severely handicapped!
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Jon Inactive Member |
We are talking about relatively small populations spread over very large geographical distances. The distance isn't important per se. What is important is that we have a single population, whose status as a single population is maintained by regular and frequent interbreeding of neighboring groups (what we've been calling the smaller populations). Jon Check out No webpage found at provided URL: Apollo's Temple! Ignorance is temporary; you should be able to overcome it. - nwr
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jar Member (Idle past 425 days) Posts: 34026 From: Texas!! Joined: |
Of course the distances are both relevant and significant.
Jon writes: What is important is that we have a single population, whose status as a single population is maintained by regular and frequent interbreeding of neighboring groups (what we've been calling the smaller populations). So you have asserted, but that is all. Anyone so limited that they can only spell a word one way is severely handicapped!
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sfs Member (Idle past 2564 days) Posts: 464 From: Cambridge, MA USA Joined: |
quote:I'm afraid I'm having trouble understanding what your model is here. If there had been a single population with some regional diversification and a constant flow of genes between neighbors, how did 95+% of Scandinavian alleles come to be of African origin, while virtually no African alleles are of Scandinavian origin? What kind of gene flow could possibly produce that situation, short of substantial numbers of people moving (on average, and over many generations) from Africa toward Scandinavia?
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Nuggin Member (Idle past 2523 days) Posts: 2965 From: Los Angeles, CA USA Joined:
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I'm afraid I'm having trouble understanding what your model is here. If there had been a single population with some regional diversification and a constant flow of genes between neighbors, how did 95+% of Scandinavian alleles come to be of African origin, while virtually no African alleles are of Scandinavian origin? What kind of gene flow could possibly produce that situation, short of substantial numbers of people moving (on average, and over many generations) from Africa toward Scandinavia?
While it is true that the Human population can be split quite easily as "those who never left Africa" and "everyone else", I think what Jon's shooting for is: "They are all human". The difference between the most "African" African and the most "Swedish" Swede really isn't that different at all. Scientists have been very successful at picking out and labeling differences between various populations, largely because the differences give us information. Noting the 99% of genes that are identical and provide no usable information about population dynamics or movements, doesn't really make for good publishing material. Further I think Jon is trying to point out that in the pre-historical past, the historical past and the present, humans are particularly good at getting around and getting it on. It's hard to find anyone in a modern society who is ethnically pure. But that's not just something from a modern society. I'm sure if you were in ancient Rome, you'd likely meet someone who's father was a Gaul and who's mother came from Egypt or whatever. The lack of differences between populations, and our ability to flow genes between groups which are relatively isolated, means that it is extremely unlikely in our current situation that we'll see a split of humanity into two distinct species. At least, that's what I'm getting from him.
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Coyote Member (Idle past 2137 days) Posts: 6117 Joined: |
Good post.
I've been avoiding this thread because it has become too pedantic. When I studied evolution/fossil man for my Ph.D. exams, I was taught the multi-regional hypothesis. This was some xxxxxx [censored] decades ago. Since then the Out of Africa hypothesis has come to dominate. But there are still some bits of the multi-regional hypothesis which seem to be accurate--those are the same ones that led to that hypothesis in the first place. Overall, it was incorrect, but those some bits remain. Ones I remember from grad school are primarily from Asia, and include such traits as shovel-shaped incisors. These traits, called line traits, show continuity from early populations, such as Home erectus, to modern humans. So whatever model you come up with, obviously some form of OoA, you will need to account for the persistence of a few line traits in eastern Asia.
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Blue Jay Member (Idle past 2728 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Hi, Jon.
Jon writes: I would say OOA proposes a very similar phenomenon. Interestingly, such events leave specific types of evidence; none of such evidence has been found, as far as I am aware, regarding sapiens and pre-sapiens. Have you not been reading my last several posts? I think I've done a good job showing you that the types of evidence we would expect to see from a migration event are exactly the types of evidence that we do see. And, your response to that is a vague reference to an undefined "specific type of evidence" which you claim is lacking. This is highly rude and disingenuous debate style, Jon. Please put some effort into it. Until you start defining these vague things you're referring to, I don't see any reason to put any stock in any argument you've made. -----
Jon writes: But our population boundaries aren't real; they're arbitrary. We don't actually have distinct and separate populations; we have just one. And we don't need massive migrations to move genes around within single populations. We do if that one population consists of about 1 million people spread out over a landmass that covers 1/6th of the planet's surface. -----
Jon writes: What happens in any population of interbreeding individuals? Do they evolve on a whole as a population, or does every evolutionary innovation require a massive migratory takeover by the members carrying the novel genes? We're not talking about novel genes, Jon! We're talking about entire genomes! Please assimilate this important detail! A single allele can easily become fixed in a population through simple admixture if natural selection favors it over all competing alleles. But, we're not talking about a single advantageous allele or an arbitrary number of advantageous alleles percolating through a vast, hybrid population: we're talking about entire genomes---non-coding DNA that is irrelevant to fitness included---saturating the global gene pool. For this, the evidence says that we do need migration. Genetic admixture is a wonderful explanation for why a handful of alleles from Neanderthals and Denisovans can be found in modern human populations. But, it is a very lousy explanation for why Paleo-African alleles dominate every modern human genome that has ever been studied. -----
Jon writes: Only some of these are the type of specific movements proposed by OOA, though. Certain of them are perfectly compatible with MH, along with being expected behaviors of early humans. Here you go again. What specific types of movements? I have challenged your assertion that OOA is formulated around a specific type of movement, and you just keep re-asserting it. And, I can't resist pointing out that the "expected behavior" of nomadic peoples is migration. That's pretty much the definition of "nomad." -Bluejay (a.k.a. Mantis, Thylacosmilus) Darwin loves you.
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Blue Jay Member (Idle past 2728 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Hi, Jon.
I just noticed that I have apparently once again set off Coyote's "pedantic" alarm. Obviously, I should back out now so Coyote can feel like he can participate in a topic about his area of expertise. It's been fun: I hope I didn't offend you too badly. -Bluejay (a.k.a. Mantis, Thylacosmilus) Darwin loves you.
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New Cat's Eye Inactive Member |
Have you not been reading my last several posts? I think I've done a good job showing you that the types of evidence we would expect to see from a migration event are exactly the types of evidence that we do see. And, your response to that is a vague reference to an undefined "specific type of evidence" which you claim is lacking. This is highly rude and disingenuous debate style, Jon. Please put some effort into it. Until you start defining these vague things you're referring to, I don't see any reason to put any stock in any argument you've made. I see you've met Jon. Get used to it... that's the only way he plays.
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sfs Member (Idle past 2564 days) Posts: 464 From: Cambridge, MA USA Joined: |
quote:True, but completely irrelevant to distinguishing between OoH and MR models. quote:Also true, but again, I don't see the relevance. quote:Since the populations we're discussing (African archaic Homo, Neandertals and Denisovans) were more isolated than modern populations and far more diverged genetically, again, I don't see what this has to do with subject at hand.
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Nuggin Member (Idle past 2523 days) Posts: 2965 From: Los Angeles, CA USA Joined: |
I don't see the relevance. Not trying to be relevant, trying to explain what he's trying to convey.
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