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RE: Yukon fossils represent a pivotal moment in evolution
June 13, 2011 at 12:01 am
Quote:As evidence builds, theories are refined or replaced. I am not particularly married to the out-of-Africa theory so it would not be too devastating to find out that it is wrong.
I agree with you Ryft but there are generations of scholars who got their PH.D.s by promoting Out of Africa and they are going to have a shit fit about this. There is a book called The First Americans by Chris Hardaker which deals with the almost equally entrenched "Clovis-First" paradigm in the Americas. Hardaker's book is interesting in many places but never more so than when he describes the potential career-suicide by anyone who questioned Clovis-First. I recommend it.
Even in science one must guard against a theory becoming dogma.
Shel, its a question of DNA. If both Neanderthal (HNS) and Homo Sapeins ( HSS) descended from Homo Erectus it would explain a lot of things. For generations the OOA crowd insisted that there was no interbreeding between HSS and HNS. That has now been disproven. What we desperately need is an uncontaminated sample of Homo Erectus DNA to sequence.
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RE: Yukon fossils represent a pivotal moment in evolution
June 13, 2011 at 2:50 am
Archaeology and Paleontology gives us an incomplete picture, because very little gets preserved in the archeological and fossil record.
The genetic record on the other hand is much more complete and it shows modern humans are descended from a group of humans who lived in East Africa. Also everybody outside Africa is descended from one band of migrants who left Africa, with only minimal intermarriage with the hominid species which they replaced.
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RE: Yukon fossils represent a pivotal moment in evolution
June 13, 2011 at 4:40 am
I like learning or hearing of new things. Keep up the post .
Live every day as if already dead, that way you're not disappointed when you are.
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RE: Yukon fossils represent a pivotal moment in evolution
June 13, 2011 at 5:10 pm
(June 13, 2011 at 2:50 am)Ziggystardust Wrote: Archaeology and Paleontology gives us an incomplete picture, because very little gets preserved in the archeological and fossil record.
The genetic record on the other hand is much more complete and it shows modern humans are descended from a group of humans who lived in East Africa. Also everybody outside Africa is descended from one band of migrants who left Africa, with only minimal intermarriage with the hominid species which they replaced.
That's the theory which is now under attack, Zig.
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RE: Yukon fossils represent a pivotal moment in evolution
June 13, 2011 at 8:30 pm
(June 13, 2011 at 5:10 pm)Minimalist Wrote: (June 13, 2011 at 2:50 am)Ziggystardust Wrote: Archaeology and Paleontology gives us an incomplete picture, because very little gets preserved in the archeological and fossil record.
The genetic record on the other hand is much more complete and it shows modern humans are descended from a group of humans who lived in East Africa. Also everybody outside Africa is descended from one band of migrants who left Africa, with only minimal intermarriage with the hominid species which they replaced.
That's the theory which is now under attack, Zig.
How so the minimalist? So far genetic analysis shows that Asians and Europeans have around 2.5% Neanderthal DNA, while the Paupa New Guineans have 4.8% Denisovan (The recently discovered Asian Cousin of Neanderthals) DNA. Apart from that small amount of intermarriage with both Neanderthals and Denisovans, modern humans outside Africa are descended from a migration which occurred no more than 125,000 years ago.
http://www.nytimes.com/2010/12/23/scienc...estor.html
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RE: Yukon fossils represent a pivotal moment in evolution
June 13, 2011 at 8:34 pm
(June 12, 2011 at 11:46 pm)Shell B Wrote: (June 12, 2011 at 9:14 pm)Ryft Wrote: (June 12, 2011 at 8:54 pm)Minimalist Wrote: As long as we are talking about fossils, this one could blow the Out of Africa crowd out of the water ... [snip rest]
As evidence builds, theories are refined or replaced. I am not particularly married to the out-of-Africa theory so it would not be too devastating to find out that it is wrong. It has never quite added up right for me anyway so I have always been open to a better theory. Thanks for the link to this.
I do not think it is impossible that convergent evolution may have happened in the span of human history as well. Why couldn't we have humans in Asia and Africa, evolving separately, but filling the same ecological niche? Obviously, unlike other convergent species, we have covered the globe, so there is no need for more than one human species on Earth any longer. However, that does not mean that it did not start that way.
You misunderstand the concept of convergent evolution. Convergent evolution deals only with superficial similarities like the shape of whales to those of the fish. The evolution of the genome of two different species never converge. The genes of whales did not, can not, grow more similar to those of the fish. No species will ever arise from a merging of the whale and the fish. It is impossible that homo sapiens descended from two or more extinct homo or pre-homo species. There can only be one species that is the direct ancester of homo sapien.
This fact is a unbreakable constraint that any theory of homo sapien origin must observe.
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RE: Yukon fossils represent a pivotal moment in evolution
June 13, 2011 at 9:03 pm
Quote:How so the minimalist?
Because if Homo Erectus at Dmanisi pre-dates HE in Africa then the Out of Africa argument becomes In To Africa. We have an assertion that HE began in Africa and from there colonized most of the world but if that assertion is shown to be false where does that leave OOA?
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RE: Yukon fossils represent a pivotal moment in evolution
June 13, 2011 at 11:55 pm
Another recent report, this time from Malaysia.
http://malaysiabreakingnews.blogspot.com...r-her.html
Quote:“I took back the axe to USM and sent it through a CT scan. It read 1.7 to 1.8 million years old,” says Mokhtar, holding up a suevite rock in the oil palm plantation, his quiet voice loud in verdant ground on a Sunday morning.
“We then sent it for fission track dating by the Geochronology Laboratory in Tokyo, which put it down to about 1.83 ± 0.61 million years old.
“That makes the tools here the oldest in the world to date. The ones in Africa — the oldest stone hand axe — is 1.5 million years old.” Sometime last year, Mokhtar found several fragments of bone, including a long bone and a finger, embedded in a suevite rock. The pieces have been sent for scientific testing.
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RE: Yukon fossils represent a pivotal moment in evolution
June 14, 2011 at 2:21 am
(June 13, 2011 at 9:03 pm)Minimalist Wrote: Quote:How so the minimalist?
Because if Homo Erectus at Dmanisi pre-dates HE in Africa then the Out of Africa argument becomes In To Africa. We have an assertion that HE began in Africa and from there colonized most of the world but if that assertion is shown to be false where does that leave OOA?
I am fairly ignorant when it comes to Homo Erectus as opposed to Homo Sapiens. Regardless of where homo erectus first emerged, the OOA theory for Homo Sapiens still stands.
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RE: Yukon fossils represent a pivotal moment in evolution
June 14, 2011 at 2:57 am
Speak kindly of HE. He may well turn out to be an ancestor of yours.
Not too long ago paleo-anthropologists were "sure" that HNS and HSS never interbred. Now we know that they did which means that if you wish to define "species" as a group which can only breed successfully with itself it means that these are NOT separate species. The relationship between the wide-ranging HE and later hominids is equally hazy.
We may well turn out to be them.
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