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Author Topic:   Leakey vs Johanson
Member (Idle past 3902 days)
Posts: 122
From: London., UK
Joined: 05-23-2003

Message 11 of 17 (50680)
08-15-2003 5:52 PM
Reply to: Message 1 by Andya Primanda
05-28-2002 6:28 AM

Leakey vs Johanson
Currently I am translating a book by Richard Leakey. One of the first things to be obvious is that Leakey has a bias; he does not consider any australopithecines to be directly ancestral to Homo sapiens. I can't help but feel that he may be wrong, however he cites studies of their middle ear, posture, rib cage, etc. to back up his position.
I believe that Louis Leakey (Richard Leakey's father) did believe that human origins were much farther back than then believed, and that thus Australopithecus could not be ancestral. Richard Leakey may well initially have supported that position.
Since then, Australopithecus species have been found in earlier strata (back to c4 million years ago), and no Homo fossils below c2million.
Since then, Richard Leakey certainly accepts the standard view. He does have some detailed objections, and does not fully accept the current lineages.
However, in his book "Origins Reconsidered", 1992 (BTW the "Reconsidered" bit is refering to an earlier book "Origins", not Evolution) in Chapter 7, he includes 5 possible lineages consistent with the fossil evidence.
All have aferensis as an ancester, 4 have africanus.
All have robustus and bosei as cousins.
His view is basically that the hominids split from the chimpanzee line c7.5 million years ago when a period of global cooling split up the forests: the chimps ancestor stayed in the woods, the hominids ancester went to (or was trapped in) the new plains. Bipedalism developed at this point.
The next split was c2.6 million years ago when the climate started to dry out, and the lineages split again. The Australophecus' maintained the largely vegetarion diet, but adapted to cope with the harder grain seed: hence the robust forms, while the ancestors of homo became hunters.

This message is a reply to:
 Message 1 by Andya Primanda, posted 05-28-2002 6:28 AM Andya Primanda has not replied

Replies to this message:
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