TEMPE, Ariz. Your mother always told you not to use your teeth as tools to open something hard, and she was right. Human skulls have small faces and teeth and are not well-equipped to bite down forcefully on hard objects. Not so of our earliest ancestors, say scientists. New research published in the February 2009 issue of Proceedings of the National Academy of Sciences reveals nut-cracking abilities in our 250-million-year-old relatives that enabled them to alter their diet to adapt to changes in food sources in their environment.
Mark Spencer, an Arizona State University assistant professor, and doctoral student Caitlin Schrein in ASU's School of Human Evolution and Social Change, are part of the international team of researchers who devised the study featured in the article "The feeding biomechanics and dietary ecology of Australopithecus africanus." Using state-of-the-art computer modeling and simulation technology the same kind engineers use to simulate how a car reacts to forces in a front-end collision evolutionary scientists built a virtual model of the A. africanus skull and were able to see just how the jaw operated and what forces it could produce.
"We started with a CT scan of a skull that is one of the most complete specimens of A. africanus that we have," said Spencer, researcher in ASU's Institute of Human Origins and a lead investigator on the project, which was funded by the National Science Foundation and European Union. This would be a later ancestor of Lucy STS5 - who is affectionately known as "Mrs. Ples." The skull, discovered in 1947, has struts on the side of the nose, but no teeth. "We meshed those data with another specimen with teeth to make the virtual model of the bone and tooth structure.
"Then we looked at chimpanzees, who share common features with Australopithecus, and took measurements of how their muscles work and added that to the model. We were able to validate this model by comparin
|Contact: Jodi Guyot|
Arizona State University