Re: Australopithecus, Homo erectus, single species hypothesis

17 Feb 1995 01:05:57 GMT

In article <3i0862$7p4@jupiter.WichitaKS.NCR.COM>, (Jim Foley) writes:
>In article <3hrq6a$>, <cc3265@albnyvms.bitnet>
>>In article <3hrdbh$62s@jupiter.WichitaKS.NCR.COM>,
>> (Jim Foley) writes:
>>>Given that Louis Leakey et al had apparently disproved the single
>>>species hypothesis 12 years previously, why were R. Leakey and Walker in
>>>1976 writing as if it was still widely accepted?
>>>Was the 1964 evidence for different hominid species living side by side
>>>not as strong as claimed?
>>Personally, I think it was very strong evidence. However, you have to
>>understand the field of paleoanthropology -- a very contentious group, full
>>of big egos. The Single Species Hyp. was championed by some very big names
>>in the field (notably Don Johanson, of "Lucy" and PBS specials fame) and
>>so required quite a bit of evidence to be laid to rest.
>I can't understand this. Johanson was nobody until he made his big
>finds in 1973 (knee joint), 74 (Lucy) and 75 (First Family). He (and
>Taieb) published a paper in early 1976 (a few months before Leakey's
>paper), in which I believe he claimed that the First Family finds were a
>mixture of Homo and Australopithecus specimens (I haven't yet read this
>paper). That doesn't make Johanson sound like an advocate of the single
>species hypothesis.

Yeah, you're right about that, though I haven't read the article in question.
As I understand it, he has changed opinion on this matter at some point in
his career. He and Tim White developed a phylogenic tree in '79, in which
they postulated afarensis as the common ancestor of all the Plio-Pleistocine
hominids. It shows africanus going to robustus, then a dead end, on one
branch; habilis to erectus to sapiens on the other. I'm not sure who was
championing it before him, his is the name I've always heard associated with
it. There's probably lots of folks around here who know the story better than
I. I do know that OH62, the specimen Johanson found and named "habilis" was
the subject of his book "Lucy's Child," (something else I haven't read :) )
which I believe discusses his hypothesis. Come to think of it, the earliest
date I know of for habilis is 2mya, while the afarensis material, which
includes, I believe, the "First Family" (somebody correct me if I'm wrong, I
don't have my notes in front of me) has a date of around 3.2mya. So, I
doubt that Johanson would claim they were cohabitating. (Maybe we should
*both* read this article :) )
Anyway, the original point that I was trying to make was that, in this
field, it takes *alot* of data to get someone to give up their pet theory,
and, unfortunately for the science as a whole, some people won't even do
it then.