Prehistoric Bones Point to First Modern-Human Settlement in Europe
for National Geographic News
|May 19, 2005|
Scientists have confirmed that bones found in the Czech Republic represent the earliest human settlement in Europe.
The collection of bones, which include samples from two males and two females, was excavated from the site of Mladec more than a century ago. Scientists have until now failed to date the fossils accurately.
The new research, using radiocarbon dating, has shown the bones to be about 31,000 radiocarbon years old.
(Radiocarbon years and calendar years don't always match. Radiocarbon dating is based on the decay rate of Carbon 14, a radioactive form of carbon present in the atmosphere that is absorbed by all living things.
Atmospheric abundance of Carbon 14 has varied over time. This makes it difficult to assign calendar dates to the fossil remains of organisms from certain time periods, as in the case of the Mladec bones.)
Modern humans began moving into Europe about 40,000 years ago. At the time, the Neandertals (also called Neanderthals) were still present in Europe. The two groups lived alongside each other until the Neandertals disappeared around 28,000 years ago.
Scientists say the Mladec remains are pivotal to the understanding of how and when Europe's first anatomically modern humans, commonly known as Cro-Magnon, arrived on the continent. The remains may also suggest clues to the relationship between humans and Neandertals, an issue that has been greatly debated.
"Some of the specimens show Neandertal-like features, but others do not," said Eva Wild at the Vienna Environmental Research Accelerator Laboratory at the University of Vienna, Austria. "The discussion will continue, in our opinion, in the direction of probable interbreeding."
Wild is one of the co-authors of the study, which is reported in today's issue of the academic journal Nature.
The Mladec bones are not the oldest human remains found in Europejust the oldest bones that indicate a human settlement, or community. Two human cranial fragments, found at the site of Pestera cu Oase in Romania, are believed to be older than the Mladec remains and date back 35,000 radiocarbon years.
The Mladec remains are a complete assemblage of early modern human fossils. The site contains remains of at least half a dozen individuals, including children. The range allows for the study of population variability.
Many of the Mladec remains were destroyed at the end of World War II in a fire in the Mikulov castle on the Czech-Austrian border.
Several attempts have been made to accurately date the remaining fossil assemblage accurately by dating the surrounding soil and animal remains, but the attempts have all failed.
The scientists behind the new study used a technique called accelerator mass spectrometry to show that the remains are about 31,000 radiocarbon years old.
"They are clearly morphologically modern and help establish that modern humans had entered Europe by 30,000 years ago," said Fred Smith, the chair of the Department of Anthropology at Loyola University in Chicago, Illinois. Smith was not involved with the study. (Morphology denotes the form and structure of an organism or its parts.)
"This is important because other finds that had been interpreted as demonstrating this are now known to be younger," Smith said.
The specimens all date to a time period belonging to the Aurignacians, an early modern human culture that existed about 30,000 to 40,000 years ago.
The Mladec collection also includes Aurignacian tools and art associated with early modern humans. At this time, bone and antler tools became common. Also, humans began to wear beads and pendants and to create bone flutes.
"The dating of the finds is important for the verification of the assumed Aurignacian origin of the fossils, and for the determination of their position within this cultural time period," said Maria Teschler-Nicola of the Natural History Museum of Vienna, Austria. She is a co-author of the study.
It is impossible to completely rule out the likelihood that the Neandertals may have made the artifacts that surround the Mladec remains. But the bones themselves are universally accepted by scientists as those of early modern humans, not Neandertals.
But there has been great debate over whether the remains show some Neandertal features or are the same as modern human remains, in terms of their structure and form.
"The Mladec individuals do not consistently exhibit the same Neandertal skeletal features, to whatever extent they possess them, nor do they yield any trace of Neandertal DNA," said Theodore Schurr, an anthropology professor at the University of Pennsylvania in Philadelphia.
"Therefore, based on these data, the Mladec remains show no strong evidence of interbreeding between Neandertals and anatomically modern humans, despite this population [of humans] having been around when Neandertals still lived in Europe."
A clear distinction between Neandertal and modern human features would support the "Out of Africa" theory, which holds that early modern humans dispersed from Africa and into Europe, where they replaced the Neandertals.
The new study does not specifically address the question of interaction between Neandertals and modern humans.
But some experts believe that humans and Neandertals interbred and that Neandertals, therefore, contributed to human ancestry.
"Many of us feel that there is evidence of some contribution of Neandertals to this early modern gene pool," said Smith, the Loyola anthropologist.
"This is reflected in certain details of the anatomy of some Mladec remains," he said. "For instance: the presence of remnant [rear skull] bones that are not present in the early modern Africans and Near Easterners. "
Smith acknowledges that other scientists believe these similarities between Mladec and Neandertal bones are just the result of random change and do not indicate any Neandertal contribution.
"However, now knowing that the Mladec sample is indeed a very early modern sample is important, regardless of which side of the debate one stands on," he said.
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