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FLASH!

Ardi Talk on November 18!

"Human Evolution: The New Fossil Ardipithecus, a Foot on the Ground & a Hand in the Trees!"

An evening with the scientists who discovered and analyzed this exciting new fossil hominid
Wednesday, November 18, 2009
7 p.m. Cleveland Museum of Natural History Auditorium
The Institute for the Science of Origins is fortunate to have among its fellows, the scientists involved in the discovery and analysis of the most exciting new human ancestor since Lucy. Come hear about "Ardi" first hand!

Sponsored by the Institute for the Science of Origins

Free and Open to the Public!

ISO Fellows Discover Earliest-Known Skeleton of Human Ancestor

4.4 million year old Ardipithecus ramidus skeleton discovered and analysed by ISO researchers

ISO Fellows Yohannes Haile-Selassie, Bruce Latimer, Linda Spurlock, and Scott Simpson

Meet the Scientists! ISO Talk on campus by Researchers - Coming Soon!

Stay Tuned - Date & Location to be announced

Yohannes Haile-Selassie, who found the fossil in Ethiopia, is curator of Physical Anthropology at the Cleveland Museum of Natural History. Spurlock is director of Human Health at CMNH. Haile-Selassie and Latimer are adjunct professors in the departments of anthropology, anatomy, and cognitive science at CWRU. Simpson is Associate Professor of Anatomy at CWRU's Medical School. All are fellows of the Institute for the Science of Origins.

These ISO scientists are helping rewrite the book on human evolution. They contributed to 7 of the 11 papers published in the journal Science, in which researchers describe the oldest hominid skeleton discovered to date, a possible human ancestor in the midst of changing from climbing on all fours to walking upright. This hominid, named Ardipithecus ramidus, or Ardi for short, is truly intermediate between humans and their ape-like ancestors. But Ardi is far different from the modern chimpanzee, which so often has been used as a model of our forebears.

"It looks, in many ways, more like a modern human," said paleontologist Scott W. Simpson, a Research Fellow at the Institute for the Science of Origins. "It's completely different from what we predicted," said Simpson, a co-author of three of the papers. "This changes not only the way we think about human ancestors, but chimpanzees and monkeys, too." Humans, chimps and gorillas have an older, common ancestor still to be found, but this skeleton shows that chimpanzees and gorillas have evolved away from us over the past 5 million years, he said. "This is one of those quantum leaps in understanding."

Yohannes Haile-Selassie, Research Fellow at the Institute for the Science of Origins, discovered the skeleton in 1994. The fossilized bones were between two layers of volcanic ash in the Middle Awash study area, a site near the Awash River in Ethiopia. They include parts of a skull, pelvis, ribs, forearm and hand, lower leg and foot. "I knew it was an early hominid remain, but at that point, there was no way I could understand the impact it would have," Haile-Selassie said. Now, after 15 years of study, the find "is Amazing. It's going to open up a lot of discussions and new questions."

Studies of the bones show that Ardi had:

Feet with a grasping big toe used for climbing, but the outer potion of the foot had the bone structure and muscle attachments used for upright walking.

Hands that differ greatly from modern chimps and gorillas, with a larger and more muscled opposable thumb. The hands are those of an animal that climbed, fed and nested differently from apes, and required little change in structure to enable it to make and use tools.

A flexible wrist, different from the stiff wrist chimps and apes rely on for knuckle-walking. On branches, Ardi walked on its palms, hand over hand.

Arms and legs more in proportion with monkeys than with the long arms and short legs of modern apes.

A mobile lower back with more vertebrae than the stiff backs of African apes.

Much smaller, diamond-shaped canine teeth and no structure to hone large canines on lower teeth, as modern chimpanzees and apes have. The modern animals use canines for tearing flesh in battles for dominance.

A diet of soft leafs and fruits, invertebrates and maybe small vertebrates. Teeth structure, enamel and wear show Ardi lacked the adaptations seen in Lucy and modern humans to eat abrasive foods.

Ardi was likely a large female, weighing about 110 pounds. The species -parts of others have been found- had not developed the large brain of modern humans. Fossils recovered from the same layers include kudus and numerous monkeys show that Ardi and her kin lived in closed woodland areas and not the open savannah.

The information above was adapted from CWRU Press Coverage