Human evolution is the process by which humans developed from pre-human ancestors. The fossil record of human ancestors is patchy and unclear. Some anthropologists believe that our ancestry can be traced back to one or more species of australopithecines that flourished in south and east Africa between 4 and 1 million years ago. Others believe we are descended from some as yet undiscovered ancestor.
The earliest fossils that can be identified as human are those of Homo habilis (handy people), which date from 2 million years ago. The next evolutionary stage was Homo erectus (upright people), who first appeared about 1.5 million yr ago. The earliest species of our own species, Homo sapiens (wise people), date from about 250,000 years ago. An apparent side-branch, the Neanderthals (Homo sapiens neanderthalis), existed in Europe and western Asia about 130,000–30,000 years ago. Fully modern humans, Homo sapiens sapiens, first appeared about 100,000 years ago.