2.8 million year old jawbone found in Ethiopia
The fossil of a lower left side jawbone, complete with 5 teeth, was discovered by an Ethiopian student in the Ledi-Gerau research area of Afar Regional State. This new discovery is significant for several reasons. For one, because of its age, it pushes the human line that was originally estimated to be 2.35 million years ago, back by 400,000 years. This links the fossil closer to the famous 3.2 million year old hominin (human-like primate) "Lucy" that was found in the same area in 1974.
The back molar teeth are smaller than those of other fossilized hominins found in the region. These molars are a feature that distinguishes humans from their more primitive ancestors, according to William Kimbel, director of Arizona State University's Institute of Human Origin.
The significance of this suggests that this hominin may have evolved as a result of climate change, when lush forest had become dry grassland therefore enabling the ancient human-like primates to come down from the trees and forage on the ground. As a result, their brains developed intellectually and, instead of relying on large jaws and teeth, they learned to create and use tools.
Ethiopia has always been one of the areas where human-like fossils have been discovered, however, other human fossils found in South Africa suggest several different species of humans co-existing around 2 million years ago, with only one of them surviving and eventually evolving into our species, Homo Sapiens.
It is as if nature made several different version of humans with the same evolutionary make up until one succeeded.