Re: We were never knuckle draggers

Yes, that's obvious: knuckle-walking is more derived than bipedalism: in
order to evolve from palm-walking (all primates incL.human infants, except
chimps & gorillas) to knuckle-walking (walking on the dorsal instead of on
the ventral side of the hand), chimps & gorillas needed an intermediary
phase where their hands were +-not used for pronograde locomotion. This
intermediary phase was not arm-hanging (alone): otherwise gibbons & orangs
would knuckle-walk on the ground, but they're palm-walkers. All apes still
walk regularly or occasionally on 2 legs, so the intermediary phase was
(short-legged) bipedalism (probably in combination with climbing arms
overhead).

--Marc Verhaegen
http://allserv.rug.ac.be/~mvaneech/Fil/Verhaegen_Human_Evolution.html
______

Op 03-06-2007 00:50, in artikel
QI2dnVhn2OGsafzbnZ2dnUVZ_o2vnZ2d@xxxxxxxxxxx, MClark <men@xxxxxxxx> schreef:

/Upright walking may not have been uniquely human/
Ann Mcllroy, Toronto Globe and Mail

Early humans didn't start out walking on all fours like gorillas and
then slowly straighten up, a team of British researchers says. Instead,
our ancestors became two-footed while nimbly traversing tree branches
in search of fruit. When ancient rain forests began to thin out, they jumped
down from the trees and started walking on the ground.

"They stayed doing what they were doing in the first place," says Robin
Crompton, with the Department of Human Anatomy and Cell Biology at
the University of Liverpool.

His work, published in the latest edition of the journal Science, is based
on the fossil records and observations of orangutans. It challenges the
widely held notion that upright walking is uniquely human, something that
distinguishes us from our closest relatives, the great apes.

Orangutans do it all the time, Crompton says. They navigate skinny branches
on two feet, grabbing higher branches with their hands to help with their
balance.
They can also walk two-footed on the ground.

Early humans didn't start walking upright so they could wade into water to
find
food, more easily carry their babies or travel more quickly and efficiently
on the
savannah, Crompton says, dismissing competing theories about the evolution
of bipedalism.

Instead, they learned how to walk in trees, and eventually did the same on
the
ground. "Bipedalism is nothing new. It is not the dramatic change that
people
portray it as," he says.

Studying orangutans offered a chance to gather evidence for an alternative
explanation.
Crompton's colleague Susannah Thorpe at the University of Birmingham spent
a year in the Sumatran rain forest observing orangutans. The team concluded
that
two-footed walking helps orangutans survive because it allows them better
access to fruit.

They argue that ancient apes - including our ancestors - probably did the
same
thing and that upright walking offered an advantage once they climbed down
from the trees.

The ancestors of chimps and gorillas, on the other hand, became more
specialized
at going up and down trees - holding on with both their hands and feet. They
kept
that same posture on the ground, which is why they often knuckle-walk,
supporting
their weight with their hands and feet.

While the new research offers an explanation for why ancient apes could
walk upright, it also complicates the work of paleontologists, who have
used evidence of two-footed walking as key criteria for distinguishing early
human fossils from those of other apes.

"It turns it all on its head, and reopens the debate," said Paul O'Higgins,
a researcher at the University of York in Britain.

/end article/

And a poo-poo to you, too, Peanut Gallery. (You know who you are)

________________________
"For whosoever quoteth scripture endlessly
hath neither job nor hobby." II Mumbleonians 4:19



.

Relevant Pages

  • Re: DHA ... savannah and bipedalism.
    ... KWing. ... > Dropping fat babies. ... force in plantigrade walking. ... intermediate bipedalism (bipeds with abducted big toes. ...
    (sci.anthropology.paleo)
  • Re: DHA ... savannah and bipedalism.
    ... > force in plantigrade walking. ... > necessarily need broad heels, ... > Miocene hominids had no sign of KWing. ... Bipedalism & valgus knees need to be explained ...
    (sci.anthropology.paleo)
  • Re: DHA ... savannah and bipedalism.
    ... I'd think that leg length is determined by wading (cf. ... >> We took to plantigrade bipedalism because it is advantageous for getting ... as plantigrade walking uses less energy than ...
    (sci.anthropology.paleo)
  • Re: News: On Nova, Theories of How the Apes Became Us.
    ... But the program turns out not to be as interested in bones as it is in ... the preference for walking ... and chimps and gorillas both developed knuckle ... But that energy-efficient bipedalism, it turns out, did not ...
    (talk.origins)
  • Re: Early apes were parttime bipeds
    ... stages of upright walking evolved in apes ... "Origin of human bipedalism as an adaptation for locomotion on flexible ... Orangutans react to branch flexibility ... appears, so perhaps the early apes already did this, but all this does not ...
    (sci.anthropology.paleo)
Loading