Wolpoff and colleagues selected fossils from Eastern Europe and Australia for the focal point of the comparison because they thought that populations distant from the center of the ancient human population might retain easily identifiable resemblances to ancient peoples, if there were any. They compared a number of different features of the fossil skulls from the Mladec cave in the Czech Republic and a skull from the Willandra Lakes region of Southeastern Australia to the other fossil skulls that could be ancestors. In each case, they analyzed in how many respects the Mladec and Australian skulls were like the other skulls and in how many respects they were different.
They found that the Mladec and Australian skulls shared characteristics distinctive to the more ancient African and Near Eastern population. But at the same time, the fossils also had distinctive resemblances to more ancient fossils within their regions, many more than could be explained by chance alone. "These features amount to a smoking gun for continuity within these regions, " says Hawks.
The findings are the latest evidence in the continuing scientific controversy about the origin of modern Homo sapiens. Many scientists believe that all living humans can trace their ancestry exclusively to a small group of ancient humans, probably Africans, living around 100,000 years ago. This explanation, known as the Eve hypothesis or replacement theory, means that all other early human groups, whose fossils date from this time back to almost two million years ago, must have become extinct, possibly wiped out in a prehistoric genetic holocaust.
Other scientists, including Wolpoff and colleagues Hawks, Frayer, and Hunley, maintain that there is little evidence that a small group originating in a single geographic region replaced the entire population of early humans. The genetic evidence has always been unclear, Wolpoff and colleagues note, because different genes support different theories: mitochondrial genes support replacement theory while nuclear genes support the development of an older, worldwide species of human ancestors.
"In asking the question a different way, and directly addressing the fossils, this study provides compelling evidence that replacement is the wrong explanation," says Wolpoff. "Instead, the findings support the theory of multi-regional evolution. Modern humans are the present manifestation of an older worldwide species with populations connected by gene flow and the exchange of ideas. Modern human groups are very much more similar than different because of comparable adaptations to ideas and technologies that spread across the inhabited world and because of the dispersals of successful genes promoted by selection."
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Adapted from materials provided by University Of Michigan.
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MLA University Of Michigan (2001, January 12). New Fossil Study Rejects "Eve Theory" And Supports Diverse Ancestry Of Modern Humans. ScienceDaily. Retrieved December 11, 2008, from
http://www.sciencedaily.com /releases/2001/01/010111194453.htm
