Posted on 03/06/2002 7:38:41 PM PST by ValerieUSA
A new piece of evidenceone sure to prove controversialhas been flung into the human origins debate.
A study published March 7 in Nature presents genetic evidence that humans left Africa in at least three waves of migration. It suggests that modern humans (Homo sapiens) interbred with archaic humans (Homo erectus and Neandertals) who had migrated earlier from Africa, rather than displacing them.
Ancient Origins
In the human origins debate, which has been highly charged for at least 15 years, there is a consensus among scientists that Homo erectus, the precursor to modern humans, originated in Africa and expanded to Eurasia beginning around 1.7 million years ago.
Beyond that, opinions diverge.
There are two main points in contention. The first is whether modern humans evolved solely in Africa and then spread outward, or evolved concurrently in several places around the world.
The second area of controversy is whether modern humans completely replaced archaic forms of humans, or whether the process was one of assimilation, with interbreeding between the two groups.
"There are regions of the world, like the Middle East and Portugal, where some fossils look as if they could have been some kind of mix between archaic and modern people," said Rebecca Cann, a geneticist at the University of Hawaii.
"The question is," she said, "if there was mixing, did some archaic genetic lineages enter the modern human gene pool? If there was mixing and yet we have no evidence of those genesas is indicated from the mitochondrial DNA and y chromosome datawhy not?"
Alan Templeton, a geneticist at Washington University in St. Louis who headed the study reported in Nature, has concluded that yes, there was interbreeding between the different groups. "We are all genetically intertwined into a single long-term evolutionary lineage," he said.
To reach his conclusion, Templeton performed a statistical analysis of 11 different haplotype trees. A haplotype is a block of DNA containing gene variations that researchers believe are passed as a unit to successive generations. By comparing genetic differences in haplotypes of populations, researchers hope to track human evolution.
Templeton also concluded that modern humans left Africa in several wavesthe first about 1.7 million years ago, another between 800,000 and 400,000 years ago, and a third between 150,000 and 80,000 years ago.
Alison S. Brooks, a paleoanthropologist at George Washington University, is more cautious about Templeton's conclusions. "Archaeological evidence supports multiple dispersals out of Africa," she said. "The question has always been whether these waves are dead ends. Did all of these people die? Templeton says not really, that every wave bred at least a little bit with those in Eurasia.
"This has not been the majority viewpoint of geneticists up to this point," said Brooks.
Dueling Theories
The fossil record shows that about 100,000 years ago, several species of hominids populated Earth.
Homo sapiens could be found in Africa and the Middle East; Homo erectus, as typified by Java Man and Peking Man, occupied Southeast Asia and China; and Neandertals roamed across Europe.
By about 25,000 years ago, the only hominid species that remained was Homo sapiens. Scientists have conducted a considerable amount of both genetic and archaeological research in an effort to understand how this outcome occurred.
....More at link......
Please cite a real geologist or archeologist, not another nutcase.
What exactly did the Economics Professor Heinsohn "reveal" to the "European archeologists"? Has the Economics professor published results in a real scientific journal? What, exactly, are his archeological, anthropological, or geological "credentials" anyway?
As I noted before, these are just man-made definitions such as the definition of "citizen" or "adult". What's an "adult"? An 18 year old or a 21 year old?
A subspecies develops when two populations have been isolated from each other for so long that their characteristics begin to drift apart to the point that they are no longer genetically compatible to produce fertile offspring.
If the two populations of subspecies ever get back into the same geographic area and start mating regularly and producing fertile offspring, then they will revert to a common form with little difference between each other after many generations.
Since a fertile mule is a rare occurance, biologists have agreed to classify donkeys and horses as different species.
If fertile mules were to develop, they would form their own species and would share the classification of "species" with any others that they could consistently produce fertile offspring with.
Anyway, I liked this one:
It is with a profound sense of ambivalence that I write this article, taking a critical stance towards the historical reconstruction of Gunnar Heinsohn. Not only do I regard Gunnar as a personal friend; he has long been a supporter of Aeon, first as a contributor of numerous articles and also through featured appearances at various symposia. Yet the suspicion has been building for some time now that all is not well with Dr. Heinsohn's handling of the ancient sources. Since Aeon has taken an active role in publicizing Heinsohn's researches, it follows that we have a certain responsibility to keep our readers informed of recent developments and, where necessary, point out problems as they come to our attention.
The current article examines Heinsohn's attempted identification of Hammurabi with Darius, arguably the most novel and controversial claim in a historical reconstruction remarkable for its radical nature.
That's from a catastrophism site! THEY don't even beleive Heinsohn!! :P
A subspecies develops when two populations have been isolated from each other for so long that their characteristics begin to drift apart to the point that they are no longer genetically compatible to produce fertile offspring.
That should read "Species" and not "Subspecies".
Subspecies look different but their genetic characteristics are such that they can breed and produce fertile offspring on a regular basis.
Here is an artificial example...... if Collies and Beagles were naturally found in the wild on two different islands, biologists would classify them as subspecies as they look quite different but the biologists would be classify them as the same species as they can produce fertile offspring on a regular basis.
hmmm....maybe this could explain the likes of James Carville, and Monica Lewinsky.
(Italics mine.)
Gen 6:2 That the sons of God saw the daughters of men that they [were] fair; and they took them wives of all which they chose.
Hybrids, including King Tut. (I don't know about their Methelusah claims, but the pictures are good.)
Anybody wanting to get caught up on this one would be best off finding copies of Emmet Sweeney's two books which I mentioned, "The Pyramid Age", and "Genesis of Israel and Egypt".
You misspelled "a lobotomy." Hope this helps.
to get on top of the controversies involving Heinsohn and you're claiming to have done that in the last ten minutes...
No, I didn't. I'm not going to referee a food fight between two equally stupid sets of foil-head nutballs. I just thought it was funny...
Due to a shortage of interns, Gov. Clinton initiates interbreeding experiments in Arkansas.
Debate about the success of the Clinton interbreeding experiments continues with scientists divided whether the next stage should proceed.
Carville doesn't prove this theory. He proves there is life on other planets.
President Bill and as yet unknown Clinton offspring from interbreeding.
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