In 1968, when workmen discovered their bones, stone and antler tools were found in the fossil collection. They were hunters, and enjoyed art which was found in nearby caves. The body is less rugged and muscular, the face flatter, the cranium higher, and the skull wall thinner. Fossil evidence is very strong, but in the 1960's, Allan Wilson and Vincent Sarich, two prominent biochemists, started studying evolution of humankind through a process of analyzing blood proteins. Mutations are sudden changes in characteristics, such as genes.
Molecular evolution is studied through proteins and enzymes.
Humans have millions of proteins in their body and these proteins are made up of amino acids. For our purposes here, we may say that the more distant the relative, the more the amino acids differ. Wilson and Sarich determine the mutation rate by dating the blood protein, and this determines the molecular clock of a species. By using this molecular clock, they have estimated the first hominid species at 5-8 million years old, which eventually would become what we recognize as today's humans. This split in lineage is called speciation.