Based on both morphological and molecular evidence, both humans and apes share a common ancestor. What is this common ancestor? Is this distant relative an ape or a human? Not really either. These early hominids shared characteristics with both humans and apes.
About 10 millions years ago, the world's climate began to get cooler, and many of the great forests of Africa were replaced with grasslands and open woodland. In response to these changes, a new kind of animal was evolving. This new being would be the common ancestor of modern apes and humans. These new ape-like beings are called hominids, meaning "of the human line." Recall that hominids are humans and their direct ancestors.
Watch this video to learn about the first hominids that were discovered. These hominids were not of the genus Homo, but that of the genus, Australopithecus. These fossil discoveries were very important to the study of human evolution.
The first hominid was discovered in 1924 by Raymond Dart, an anatomy professor in South Africa. He found a beautifully preserved skull of a five-year-old that still had its baby teeth.
While the skull had many apelike features such as a projecting face and small brain, it had human-like features as well. It had a rounded jaw and the position of the hole at the base of the skull suggested the creature walked upright. The skull was estimated to be around 2.8 million years old and Dart named his find, Australopithecus africanus.
After this discovery, other remains of Australopithecus were found in other areas of Africa. In 1974, anthropologist, Don Johanson went to remote regions of Ethiopia looking for early human fossils and hit the jackpot. He found the most complete, well preserved Australopithecus skeleton known.
He nicknamed her "Lucy" and her skeleton was over 40% complete and estimated to be over 3 million years old. The shape of her pelvis indicated she was female and her leg bones proved she walked upright. Her teeth were distinctly hominid, but her head was shaped more like an ape. This is a reconstruction of what many thought “Lucy” looked like.
More than 300 specimens of Australopithecus have been discovered in the last few decades, showing this was a diverse group. Perhaps the evolution of hominids began with "Lucy", one of our relatives.
Question
Compared to apes, what is a major difference that Lucy and other similar fossils exhibited that made them more human-like?
