The Homo genus most likely de­scended from

Aus­tralo­p­ithe­cus afaren­sis, best known for the 3.2-mil­lion-year-old “Lucy” fos­sil found in Ethiopia’s Afar re­gion. A jaw­bone also found in the Afar marks the de­but of Homo in the fos­sil record at 2.8 mil­lion years ago. By about two mil­lion years ago, the Homo fos­sil record picks up, de­liv­er­ing ev­i­dence of at least three species lop­ing around East­ern Africa – and

What drove this early di­ver­si­fi­ca­tion? Per­haps the chang­ing cli­mate – a com­mon pre­lude to species booms. As East Africa dried out about 2.6 mil­lion years ago, forests re­treated and were re­placed with open sa­van­nahs, ter­rain favour­ing crea­tures that could run on two legs and fash­ion stone tools to hunt game.

Dis­cov­ered in 1964, Homo ha­bilis was the most prim­i­tive-look­ing of the trio, with its prom­i­nent snout, yet also ap­par­ently the most ad­vanced. He had the largest skull, and the sed­i­ments it was found in con­tained the old­est stone-cut­ting tools known at the time, as well as butchered an­i­mal bones show­ing cut marks – hence the moniker “handy man”.

For a long time, Homo ha­bilis fit­ted the bill as a di­rect rel­a­tive but re­cent work sug­gests Homo

ha­bilis was an early side-branch, pos­si­bly split­ting from the 2.8-mil­lion-year-old Ledi-ger­aru species.

Homo rudolfen­sis was a later off­shoot, while Homo erec­tus has as­sumed a cen­tral po­si­tion in the story of hu­man evo­lu­tion over the past two mil­lion years.

All Homo species that crop up later than two mil­lion years ago – in­clud­ing us – are thought to have Homo erec­tus as their fore­bear. Homo ha­bilis, or Handy Man, lived from two to 1.5 mil­lion years ago.

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