Cosmos

BIRTH OF THE HOMO

- CREDIT: ENCYCLOPAE­DIA BRITANNICA / GETTY IMAGES

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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