All humans today are members of the modern human species Homo sapiens — Latin for “knowing man.” But we’re far from the only humans who ever existed. Fossils are revealing more and more about early humans in the genus Homo — ancestors like Homo erectus (Latin for “upright man”), who lived in Africa, Asia and parts of Europe between 1.9 million and 110,000 years ago.
Scientists now recognize more than a dozen species in the Homo genus. So what, exactly, was the first human species? The answer, it turns out, is not crystal clear.
Fossil finds in Morocco have revealed that anatomically modern humans emerged at least 300,000 years ago. But the oldest human species scientists definitively know about is called Homo habilis, or “handy man” — a tool-using primate who walked upright and lived in Africa between 2.4 million and 1.4 million years ago.
However, earlier fossils hint that other Homo species may predate H. habilis. The scarcity of early human fossils makes it challenging to know if unusual specimens are a newfound species or simply an atypical member of a known species. On top of that, evolution can be gradual, so it’s hard to pinpoint when a new species emerges, especially when fossils have a mix of features from different species.
“The process of evolution is continuous, but the labels we place on it for convenience are static,” Tim D. White, a paleoanthropologist at the University of California Berkeley, told Live Science.
Related: Why did Homo sapiens outlast all other human species?
Earliest Homo
Most evolutionary theories suggest that H. habilis evolved from an earlier genus of primate named Australopithecus — Latin for “southern ape” because its fossils were first discovered in South Africa.
Various species of Australopithecus lived from about 4.4 million to 1.4 million years ago. It may be that H. habilis evolved directly from the species Australopithecus afarensis — the best-known example of which is “Lucy,” who was unearthed at Hadar in Ethiopia in 1974.
The fossils of our genus are usually distinguished from Australopithecus fossils by Homo‘s distinctively smaller teeth and a relatively large brain, which led to the greater use of stone tools.
But White noted that traits like smaller teeth and bigger brains must have emerged at times in the Australopithecus populations that early Homo evolved from.
“If you had an Australopithecus female, there wasn’t a birth at which point she would have christened the child Homo,” he…
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