In search of human origins
Fossil skull indicates Homo erectus was a single, widespread species, researchers say

By Robert Sanders, Public Affairs

This human family tree shows how the new Ethiopian fossil skull fits in with previously known Homo erectus and other hominid fossils. The circles indicate local Homo erectus populations inferred from fossil finds. Henry Gilbert graphic

20 March 2002 | A million-year-old Homo erectus skull found in Ethiopia indicates that this human ancestor was a single species scattered widely throughout Asia, Europe and Africa, not two separate species, according to an international group of scientists who discovered the skull in 1997.

Some archaeologists and anthropologists have argued that African and European populations were a different species, Homo ergaster, distinct from the strictly Asian Homo erectus.

It took Berkeley researchers and their colleagues more than two years to clean and reassemble the crushed skull, which is described by the Ethiopian and American teams in the March 21 issue of Nature.

The fossil was described by Berhane Asfaw of the Rift Valley Research Service in Addis Ababa, Ethiopia; Berkeley paleoanthropologist Tim White, professor of integrative biology and co-director of the university’s Laboratory for Human Evolutionary Studies; and Berkeley graduate student W. Henry Gilbert, who found the skull.

“This fossil is a crucial piece of evidence showing that the splitting of Homo erectus into two species is not justified,” said White. “This African fossil is so similar to its Asian contemporaries that it’s clear Homo erectus was a truly successful, widespread species throughout the Old World.”

The Ethiopian and American scientists also concluded that the onset of the Ice Ages about 950,000 years ago likely split the Homo erectus populations and led to their divergent evolutions. The African population of Homo erectus probably gave rise to modern Homo sapiens, the European branch perhaps became the Neanderthals, or Homo neanderthalensis, while the Asian population became extinct.

Homo erectus first appeared about 1.8 million years ago and, based on the fossil evidence, quickly populated Africa, Asia and Europe.

For the full story on this research, see www.berkeley.edu/news.