Read this book for the answer.
Posted on 03/06/2002 7:38:41 PM PST by ValerieUSA
A new piece of evidence—one sure to prove controversial—has 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 genes—as is indicated from the mitochondrial DNA and y chromosome data—why 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 waves—the 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......
Well that's hardly news. We also mated with snakes, as James Carville is living proof.
Read this book for the answer.
Not true. Ligers (lion/tiger mixes) exist. Years ago there was one named Shasta I used to visit with my kids at Hogle Zoo in Salt Lake City. They're not abundant but definitely exist.
I just reread your statement and maybe I misunderstood it. Are you saying leopards can't mate with either lions or tigers? Maybe so. But lions and tigers get it on productively.
Same here. The wild Bobcats will mate and have off-spring with the domesticated cats. My dad (Bless his soul), years ago, had some that were mixed.
Las' December. Y'ain't heared the news, yet?
This is an interesting possibility. But the title is all wrong. There are many species of primates, and they can all be said to be of different species...unless they can produce offspring. If they could, in fact, produce offspring then they would not be different species. They would be different varieties, or possibly different races. Because there seems to be a definite progression from Homo Erectus as the prototype, (and including several varieties in between) and the Neandertals and modern Homo Sapians as later developments, it would be most proper to call them different varieties. Different races would be more appropriate if there were several types of Home Erectus or several types of Neanderthal.
Dang! Learned something new tonight. Just did a quick search and found there are actually Zorses (Zebra/Horse), Wholphins (False Killer Whale/Dolphin); Cama (Camel/Llama); and Cattalo (Cow/Bison).
Also discovered there's a something called a Dasshole which is a cross between a Democratic Senator and a Sphincter.
Your points and others are well taken. The fact is we really don't know what happened some 100,000 years ago other than previous hominoid species died out and our specie continued to thrive. I have an open mind about the subject (I really do) but I suspect that this debate will be raging for many decades to come.
My teen-age sons love the word "sphincter" - it's just so all-purpose in the world of crass insults. *LOL*
Yup. I've got two teenage sons, also. The "sphincter" word gets a certain amount of airtime here, too.
The name "Galicia" is derived from the Celtic people who lived there prior to the time of the Roman conquest (the "Gallaeci"). There had apparently existed a fishing/sailing/trading commerce between Galicia and the British Isles and Ireland for centuries. Today, many red-headed, green-eyed Spaniards can trace geneological roots to Galicia. The modern Galician dialect however, has Portuguese roots, the Celtic origins having been almost obliterated. Galicians are considered by other Spaniards as something like country bumpkins.
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