Tuesday, February 22, 2011
Ancient Teeth Challenges Origins of Man
Most evidence for modern man is 70,000 years or less. Other evidence suggests that the human form may well have been round for as much as 400,000 years, except that evidence is not archeological and not accepted.
Besides all that, we have the real problem of successful dispersion. A successful species can disperse in a rather short time period making its fossils available throughout its full range at its moment of maximum success. Yet every such success may have been a development restricted to a small area for tens of millennia.
Imagine a successful tribal group evolving for three hundred thousand years in
Africa, but making their living on the coast and never venturing
north to contest the tropical mangroves.
At some point they develop a tool kit that allows penetration of the interior
to hunt and settle. From that moment on
they can settle the whole globe and they do so in mere thousand or so years. This is a presently reasonable conjecture.
Thus ancient evidence is always greatly interesting, but should be understood as always tentative.
Ancient teeth raise new questions about the origins of modern man
February 9, 2011
Teeth found at a site near Rosh Haain in Israel are providing new information about who the earlier occupants of this region were as well as their potential evolutionary relationships with later fossils from this same region, says Binghamton University anthropologist Rolf Quam. Credit: Rolf Quam
Eight small teeth found in a cave near Rosh Haain, central
Israel, are raising big questions about the
earliest existence of humans and where we may have originated, says anthropologist Rolf Quam.
Part of a team of international researchers led by Dr. Israel Hershovitz of Tel
Aviv University, Qaum and his colleagues have been examining the dental
discovery and recently published their joint findings in the American
Journal of Physical Anthropology. Binghamton University
Excavated at Qesem cave, a pre-historic site that was uncovered in 2000, the size and shape of the teeth are very similar to those of modern man, Homo sapiens, which have been found at other sites is Israel, such as Oafzeh and Skhul - but they're a lot older than any previously discovered remains.
"The Qesem teeth come from a time period between 200,000 - 400,000 years ago when human remains from the
are very scarce," Quam said. "We have numerous remains of Neandertals
and Homo sapiens from more recent times, that is around 60,00 - 150,000 years
ago, but fossils from earlier time periods are rare. So these teeth are
providing us with some new information about who the earlier occupants of this
region were as well as their potential evolutionary
relationships with the later fossils from this same region."
The teeth also present new evidence as to where modern man might have originated. Currently, anthropologists believe that modern humans and Neandertals shared a common ancestor who lived in
700,000 years ago. Some of the descendants of this common ancestor migrated to Europe and developed into Neandertals. Another group
stayed in Africa and evolved into Homo
sapiens, who later migrated out of the continent. If the remains from Qesem can
be linked directly to the Homo sapiens species, it could mean that modern man either
originated in what is now Israel
or may have migrated from Africa far earlier
that is presently accepted.
But according to Quam, the verdict is still out as to what species is represented by these eight teeth, which poses somewhat of a challenge for any kind of positive identification.
"While a few of the teeth come from the same individual, most of them are isolated specimens," Quam said. "We know for sure that we're dealing with six individuals of differing ages. Two of the teeth are actually deciduous or 'milk' teeth, which means that these individuals were young children. But the problem is that all the teeth are separate so it's been really hard to determine which species we're dealing with."
According to Quam, rather than rely on individual features, anthropologists use a combination of characteristics to get an accurate reading on species type. For instance, Neandertal teeth have relatively large incisors and very distinctive molars and premolars whereas Homo sapiens teeth are smaller with incisors that are straighter along the 'lip' side of the face. Sometimes the differences are subtle but it's these small changes that make having a number of teeth from the same individual that much more important.
But even though Quam and the team of researchers don't know for sure exactly who the teeth belong to, these dental 'records' are still telling them a lot about the past.
Lower premolars and canine teeth found at the Qesem cave site in
raising new questions about the origins of modern man. If linked directly to
Homo sapiens, it could mean that modern man either originated in what is now
Israel or may have migrated from Africa far earlier that is presently accepted,
says Binghamton University anthropologist Rolf Quam. Credit: Rolf Quam Israel
"Teeth are evolutionarily very conservative structures," Quam said. "And so any differences in their features can provide us with all sorts of interesting information about an individual. It can tell us what they ate, what their growth and development patterns looked like as well as what their general health was like during their lifetime. They can also tell us about the evolutionary relationships between species, all of which adds to our knowledge of who we are and where we came from."
Excavation continues at the Qesem site under the direction of Professor Avi Gopher and Dr. Ran Barkai of
The archaeological material already recovered includes abundant stone tools and
animal remains, all of which are providing researchers with a very informative
'picture' of daily life and hunting practices of the site's former inhabitants. Tel
"This is a very exciting time for archeological discovery," Quam said. "Our hope is that the continuing excavation at the site will result in the discover of more complex remains which would help us pinpoint exactly which species we are dealing with."
Quam continues to be in touch with the on-site archeologists and hopes to collaborate in the project when and if more complete human remains are recovered.