Archive for Sunday, March 24, 2002

Casts of fossils, tools define life of human ancestors

March 24, 2002


About 80 years ago, Raymond Dart was digging in South Africa and found what he recognized to be an early human ancestor. He named the specimen Australopithecus africanus.

Since then, hundreds of fossils of early human ancestors  also called hominids  have been found in Africa, and anthropologists now know that the Australopithecus species lived and died in Africa for nearly 5 million years.

A new exhibit at Kansas University's Museum of Anthropology, "Early Us (and Them) in Africa," takes a look at these ancestors  their bone structure and size, locomotion, eating habits  and how they compare with apes.

"It covers 5 million years of evolution," said David Frayer, a KU anthropology professor and curator of the exhibit. "The first (Australopithecus appeared) 6 million years ago in Africa; the last ones, 1 million years ago in Africa."

To put things in perspective: Homo sapiens, or modern man, have been around for about 40,000 years.

Frayer said the earliest human ancestors walked on two feet, used tools and had smaller brains and bodies. The brain of an Australopithecus weighed 1 pound, compared with modern man's 3-pound brain. Lucy, the famous Australopithecus fossil found in 1974 in Ethiopia, measured 3 feet, 5 inches. Her male counterpart  affectionately called Desi by Frayer  stood just under 4 feet.

The exhibit contains a cast of the Lucy fossil that is displayed alongside the cast of an ape skeleton. Lucy is thought to have been about 17 years old at her death.

"On the vertebrae of Lucy, there's extra bone growth," Frayer said, pointing at a replicate of her spine. "She had a disease related to Scheuermann's disease, a disease that affects people now."

Scheuermann's disease is a condition related to the curvature of the spinal column. It most often occurs in adolescence and changes a child's posture.

Other highlights of the exhibit are:

l A cast of Australopithecus footprints found at the Laetoli site in Tanzania. The footprints were made in volcanic ash about 3.47 million years ago and are thought to have been made by three hominids because of the arched soles and alignment of the big toes. The prints were discovered in 1975.

l Stone tools made and used by Australopithecus about 2.5 million years ago. The tools are made of flint and quartzite.

l A skull of a juvenile, about 7 years old, who was most likely killed when a leopard punctuated the skull with its two fangs.

l Photographs of the habitat in which the earliest human remains were found. Frayer said the areas of South Africa where Australopithecus were found are now dry and desertlike.

"In the past, there were swamps, lakes and streams. It was even wooded," he said. "It was wetter and a tropical environment."

Frayer said no one knows why Australopithecus became extinct.

"(The exhibit) will be humbling for people to realize that humanlike forms have been around forever," he said.

Brandi Wiebusch, one of Frayer's anthropology students who helped organize the exhibit, said the display is designed to be entertaining and educational for all ages.

"We wanted to make it fun and colorful," she said. "And you get a better understanding of evolution."

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