Re: How the australopithecine got its long arms

Stephen Jones (sejones@ibm.net)
Sun, 19 Jul 1998 21:53:02 +0800

Reflectorites

Walter ReMine has observed:

"The central illusion of evolution lies in making a wide array of
contradictory mechanisms look like a seamless whole. There is no
single evolutionary mechanism-there are countless. Evolutionary
theory is a smorgasbord: a vast buffet of disjointed and conflicting
mechanisms waiting to be chosen by the theorist. For any given
question, the theorist invokes only those mechanisms that look most
satisfying. Yet, the next question elicits a different response, with
other mechanisms invoked and neglected." (ReMine W.J., "The
Biotic Message," 1993, p24)

Here is an article from my local newspaper which illustrates this
nicely. Faced with a problem that Australopithecus africanus had
forearms that are much longer than expected, two anthropologists
Henry McHenry and Lee Berger proposed that africanus must have
gone back to the trees. But one of our local anthropologists Ken
McNamara has a `better' explanation, without even looking at the
evidence: africanus evolved long arms in order to scratch its back!

Now try to falsify that "just-so-story"!

Steve

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THE WEST AUSTRALIAN MONDAY JULY 13 1998 23

Early humans liked high life

By Carmelo Amalfi

EARLY humans returned to the trees to live about one million years
after they climbed down and mastered life on two legs, a new study
has found.

Two anthropologists are about to publish a study which suggests
Man's most immediate ancestor rediscovered its lofty lifestyle despite
having learnt to walk on land.

They found that the direct ancestor of homo sapiens redeveloped long
arms and strong back muscles like those of modern-day apes.

The study was based on a skeleton of the species Australopithecus:
africanus, which features forearms that are much longer than
expected and short hind limbs.

It was previously thought that Australopithecus africanus continued
to evolve until it had a long-legged stature and two-legged gait first
developed by an earlier species, Australopithecus afarensis.

Anthropologists Henry McHenry, of the University of California, and
Lee Berger, of the University of Witwatersrand in Johannesburg,
believe humans took a step backwards in the evolutionary process
which could have stopped them developing higher intelligence.

Professor McHenry said the skeleton showed that humans reverted to
more primitive, ape-like behaviour than previously thought.

Its long arms suggested the species spent a lot of time swinging
between branches. "There are features of the back which make it look
more like a chimpanzee, with big muscles for retracting the long
arms," Professor McHenry said. "It clearly was 'bipedal but it had
retained more climbing characteristics. "

WA Museum evolutionary biologist Ken McNamara said it was
possible Australopithecus africanus did not return to the trees.

"Maybe it is more likely that rather than returning to the trees, they
just used their long arms for other things ton showed that humans
reverted to more primitive, ape-like behaviour than previously
thought.

Its long arms suggested the species spent a lot of time swinging
between branches. "There are features of the back which make it look
more like a chimpanzee, with big muscles for retracting the long
arms," Professor McHenry said. "It clearly was bipedal but it had
retained more climbing characteristics."

WA Museum evolutionary biologist Ken McNamara said it was
possible Australopithecus africanus did not return to the trees.

'Maybe it is more likely that rather than returning to the trees, they
just used their long arms for other things such as scratching their
back," he said without having seen the authors' paper to be published
in the next issue of the Journal of Human Evolution.

They probably had the best of both worlds in which they were able to
walk upright and, if they felt like it, swing back to the trees using
their relatively longer arms."

He said the earliest australopithecines lived about 4.3 million to 4.5
million years ago. Australopithecus afarensis lived between 3.4
million and 3.8 million years ago and Australopithecus africanus
about 2.5 million years ago. By two million years ago, the genus
Homo had appeared.

(Amalfi C., "Early Humans Liked High Life," The West Australian,
July 13, 1998, p23)
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"Evolution is the greatest engine of atheism ever invented."
--- Dr. William Provine, Professor of History and Biology, Cornell University.
http://fp.bio.utk.edu/darwin/1998/slides_view/Slide_7.html

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Stephen E (Steve) Jones ,--_|\ sejones@ibm.net
3 Hawker Avenue / Oz \ Steve.Jones@health.wa.gov.au
Warwick 6024 ->*_,--\_/ Phone +61 8 9448 7439
Perth, West Australia v "Test everything." (1Thess 5:21)
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