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anthropologists classify set of recent pre-human discoveries in question
"Ardi" Is the world-famous fossil of Ardipithecus, not a human ancestor? In "Nature" anthropologists now explain that it was probably just that this and several other supposed pre-human reality in early anthropoids were. They accuse their colleagues to interpret human-like characteristics as premature phylogenetic evidence, although this may have arisen independently.
As a scientist, some years ago in Ethiopia's Afar Depression fossil skeletons of the 4,4 million year old Ardipithecus ramidus discovered, this was a sensation because the discovery was regarded as the oldest known ancestor of man. Clearly, further adjustments to the climbing, had "Ardi" on how the most complete of the fossils was baptized, some features that are clearly distinguished from that which would be expected in a human ancestor. Nevertheless, Ardipithecus was similar to the findings of some recent Orrorin tugenensis and Sahelanthropus tchadensis as Vormensch.
assigned to jump to the pre-human
But this is premature and probably wrong - explain that in any case now anthropologist at George Washington and the New York University. They criticize the tendency of many colleagues, automatically humanlike characteristics of a homology - similarity of features based phylogenetic relationship assumed. Similar adjustments to give it in evolution very often even when not closely related Species. In the interpretation of fossil primate had to be taken not especially differentiated. "Do not get me wrong, these are all important discoveries," said Bernard Wood, a professor of evolutionary anthropology at George Washington University. "But easy to assume that everything that is found in that time frame, a human ancestor has to be is naive."
characteristics are not inherited, but developed independently?
are example of some of the ape ancestors apomorphic - independently created - characteristics known in the human line, however, is not taken into account in the interpretation of fossils in most cases. In the case of Ardipithecus and Sahelanthropus such as the reduced canines as one of the most convincing evidence of their status as pre-human.
But it was the reduction of the canines, the scientists now argue , occurred well known in the line of apes several times independently. As an adaptation to a change in diet. So why is calculated Ardipithecus this adaptation inherited and have not developed independently, as so many of his relatives?
Only the "great-grandfather" of the apes?
speaks According to the researchers agree that it is in these cases to less direct ancestors, as is rather similar , perhaps even more likely ancestors of modern apes. Both lines separated according to current knowledge, six to eight million years ago. While it is easy today between modern chimps and humans differ, this is for fossils from the period several million years ago much more difficult. Because at this time, shortly after the split of the two lines, the similarities were much greater.
"We are not saying that these fossils are definitely not early human ancestors," said Terry Harrison, professor of anthropology at New York University. "But their status is assumed to be adequately demonstrated and there are a number of alternative interpretations would be possible. We believe that it is just as likely or even probable, that this is about fossil apes . Acts that are close to the common ancestor of humans and apes "
It's not the first time that an early ape is classified wrongly as early man: So was in front of about eight million years ago, Southeast Asia Ramapithecus living in the 1960s, as Vormensch, now it is clear that he is a close relative of the orang-utans. Also originating from the same time as the Oreopithecus bambolii many similarities with the early people, among others, he could probably even go up already. But many other features of its anatomy suggests that it more in the line of Ape should be classified. The similarities to early humans probably have evolved independently of them.
(New York University, 02/18/2011 - NPO).
Nota
attention beyond the circle of professionals addition, the discovery of 'Ardi' excited because he showed that the disposition was created to walk upright in our tribal history much earlier than previously thought, and that insofar as the common ancestor of humans and apes to humans looked like modern humans than apes. The new interpretation of the New York scientist would not weaken this conclusion, but rather raise: The ancestors of the ape saw the man even more similar than today's apes. For the 'meaning,' history of our species would only mean was that the origin for our species, the upright on his hind legs, not quite as big leap, as previously thought. Not quite as big, but for less mysterious.
JE
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