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| Lee Olsen... |
 Posted: Mon Oct 12, 2009 1:35 pm |
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On Oct 12, 3:55 pm, "deowll" <deo... at (no spam) gmail.com> wrote:
[quote:0973daf81c]"Lee Olsen" <paleoc... at (no spam) hotmail.com> wrote in message
news:230fb802-698f-43bb-b67e-8e2ae26a4380 at (no spam) 12g2000pri.googlegroups.com...
On Oct 12, 11:41 am, "deowll" <deo... at (no spam) gmail.com> wrote:
Or maybe an orangutan?
Why not, as Gerrit pointed out, anything at this point is better than
what the chimps ("referential model") are doing. Orangs, gibbons,
a few of the lemurs, and us are in right now.... gorillas and chimps
look like the odd-men out.
--------------------------------------
I tried to check out a web site that is supposed to show ape skeletons
including selected parts in motion but the thing didn't work for me.
The experts are contradicting each other again. I just got through reading
that Ardi would have no energy advantage in locomotion over a chimp.
Great, The problem is I can recall reading a study done using tread mills
with CO2 collection masks to check how many calories were really being used
that said chimps tended to be about as bad energy wise on two legs as four
though they were much faster than a human on four and much less energy
efficient.
They then went on to note that the longer legged chimps did do better on two
legs than some others and that enough variation existed for selection to
work with.
Right, Ardi has longer legs than a chimp and a better pelvis and foot for
erect walking to make it a much better biped than any chimp. This suggests
that the last expert was clearly wrong and if not the first expert was
wrong. Since this one isn't a my opinion is as good as your opinion type
thing I think the last guy most likely gave a wrong opinion because he
didn't bother to check what we knew about Ardi against what we knew about
energy use in Chimps when they walked/ran and bipedal locomotion in general.
[/quote:0973daf81c]
I don't doubt all that, but if hominids weren't competing directly in
the same areas
initially (cut off for some unknown reason), then slight differences
in K/W vs bipedalism
wouldn't have mattered. After all, it took us a long time to take over
the planet, leaving
chimps and gorillas to sweat it out in the rain forests on the verge
of extinction.
If the great forests hadn't disappeared, we may have ended up barking
up the wrong tree. |
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| caldervangogh at (no spam) gmail.com... |
| Posted: Mon Oct 12, 2009 3:05 pm |
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On Oct 10, 5:55 am, Gerrit Hanenburg <g.hanenb... at (no spam) inter.nl.nomail.net>
wrote:
[quote:ee04c599de]One week after the publication we've been waiting for for 15 years
this group is awfully silent on Ardipithecus
[/quote:ee04c599de]
A mere week ago, I was ducking out of this group out of sheer boredom
until "something interesting happens." Ha! Jokes on me, as we say in
the USA.
[quote:ee04c599de], while it should be abuzz
about its implications. Have we become so numb by years of acrimonious
debate about AAT and such?
[/quote:ee04c599de]
yes.
[quote:ee04c599de]Such a shame.
Anyway, some implications of Ardipithecus:
- Death of the chimpanzee referential model. The chimpanzee is not a
living fossil but is derived in several aspects, and the CLCA was not
a chimpanzee. Early hominids did not compete with chimpanzees.
[/quote:ee04c599de]
Big shake up; now what?!? <smile> I am reminded of two recent
papers.
One paper pointing out that human hair and/or chimp hair is not strong
enough to hold an infant in the upright posture. That is, the infant
proto-human would have to be carried instead of cling to his or her
mother. So, we must assume that Ardi carried her child! Why could
this not be one of the major factors in our survival, and in the
selection operating in this particular adaptive plateau?
The second paper concerned occasional "interbreeding" between our
emerging species and the chimps about 5mya. We may have had the CLCA
at, say, 7 mya, but then had contact at say, 5 mya, and that skews the
DNA dating. So, in addition to the loss of the chimp as a model, Ardi
seems to indicate that we need more time to evolve away from the CLCA
into the Ardi form.
What is your take on knucklewalking evolving twice.
The chimp model is dead. Wow. It had been under suspicion but was
all we had. Can we assume that Ardi has in common "nesting in trees"
every night, which gorillas also do?
[quote:ee04c599de]
- Death of the savanna model with regard to the origin of bipedalism.
[/quote:ee04c599de]
good.
[quote:ee04c599de]However, the habitat of Ardipithecus is reconstructed as woodland.
Woodland is already an environmental grade between closed-canopy
forest and more open environments. The Aramis environment does have a
grassy component and the isotopic data from Ardipithecus teeth signals
a C4 component of the diet between 10-25%.
More open environments are still proposed for the later adaptive
plateaus of Australopithecus and Homo.
- Four adaptive plateaus are now distinguished with regard to hominid
origins and subsequent evolution:
1) CLCA (last common ancestor of chimpanzees and humans; palmigrade
arborealist, dimorphic canines, forest frugivore/omnivore).
[/quote:ee04c599de]
?nesting in trees?
?some tool use?
?propensity to have "culture"?
[quote:ee04c599de]2) Ardipithecus (partially arboreal, facultative biped, feminized
canine, woodland omnivore). This adaptive plateau is newly proposed.
[/quote:ee04c599de]
This is wonderful, to have a whole new plateau to study.
Although the authors of these papers makes a good argument for
reproduction & feminized canines, and I do not doubt those parts I
have read, I must ask what other factors may have lead to this
reduction. Change in diet, for example?
regards
calder
[quote:ee04c599de]3) Australopithecus (striding terrestrial biped, postcanine
megadontia, Pan-African, wide niche).
4) Homo (enlarged brain, dentognathic reduction, technology reliant,
Old World range).
- Ardipithecus is on the hominid branch of the phylogenetic tree. It
shares several derived craniodental and postcranial characters with
later hominids (e.g. advanced cranial base flexion, anterior position
of basion).
- Ardipithecus represents an adaptive plateau with bipedality on the
ground but also retaining significant arboreal capability. If
Sahelanthropus also belongs here the implication is that this
"compromise" arboreal/terrestrial adaptive plateau lasted for several
million years (c. 7 mya - 4.4 mya).
Gerrit[/quote:ee04c599de] |
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| deowll... |
| Posted: Mon Oct 12, 2009 4:55 pm |
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Guest
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"Lee Olsen" <paleocity at (no spam) hotmail.com> wrote in message
news:230fb802-698f-43bb-b67e-8e2ae26a4380 at (no spam) 12g2000pri.googlegroups.com...
On Oct 12, 11:41 am, "deowll" <deo... at (no spam) gmail.com> wrote:
[quote:3b1154eeb0]
Or maybe an orangutan?
[/quote:3b1154eeb0]
Why not, as Gerrit pointed out, anything at this point is better than
what the chimps ("referential model") are doing. Orangs, gibbons,
a few of the lemurs, and us are in right now.... gorillas and chimps
look like the odd-men out.
--------------------------------------
I tried to check out a web site that is supposed to show ape skeletons
including selected parts in motion but the thing didn't work for me.
The experts are contradicting each other again. I just got through reading
that Ardi would have no energy advantage in locomotion over a chimp.
Great, The problem is I can recall reading a study done using tread mills
with CO2 collection masks to check how many calories were really being used
that said chimps tended to be about as bad energy wise on two legs as four
though they were much faster than a human on four and much less energy
efficient.
They then went on to note that the longer legged chimps did do better on two
legs than some others and that enough variation existed for selection to
work with.
Right, Ardi has longer legs than a chimp and a better pelvis and foot for
erect walking to make it a much better biped than any chimp. This suggests
that the last expert was clearly wrong and if not the first expert was
wrong. Since this one isn't a my opinion is as good as your opinion type
thing I think the last guy most likely gave a wrong opinion because he
didn't bother to check what we knew about Ardi against what we knew about
energy use in Chimps when they walked/ran and bipedal locomotion in general. |
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| deowll... |
| Posted: Tue Oct 13, 2009 12:04 pm |
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Guest
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"Lee Olsen" <paleocity at (no spam) hotmail.com> wrote in message
news:bab0cf92-a917-4524-ad03-ab12953367f3 at (no spam) t11g2000prh.googlegroups.com...
On Oct 12, 3:55 pm, "deowll" <deo... at (no spam) gmail.com> wrote:
[quote:db0724561b]"Lee Olsen" <paleoc... at (no spam) hotmail.com> wrote in message
news:230fb802-698f-43bb-b67e-8e2ae26a4380 at (no spam) 12g2000pri.googlegroups.com...
On Oct 12, 11:41 am, "deowll" <deo... at (no spam) gmail.com> wrote:
Or maybe an orangutan?
Why not, as Gerrit pointed out, anything at this point is better than
what the chimps ("referential model") are doing. Orangs, gibbons,
a few of the lemurs, and us are in right now.... gorillas and chimps
look like the odd-men out.
--------------------------------------
I tried to check out a web site that is supposed to show ape skeletons
including selected parts in motion but the thing didn't work for me.
The experts are contradicting each other again. I just got through reading
that Ardi would have no energy advantage in locomotion over a chimp.
Great, The problem is I can recall reading a study done using tread mills
with CO2 collection masks to check how many calories were really being
used
that said chimps tended to be about as bad energy wise on two legs as four
though they were much faster than a human on four and much less energy
efficient.
They then went on to note that the longer legged chimps did do better on
two
legs than some others and that enough variation existed for selection to
work with.
Right, Ardi has longer legs than a chimp and a better pelvis and foot for
erect walking to make it a much better biped than any chimp. This suggests
that the last expert was clearly wrong and if not the first expert was
wrong. Since this one isn't a my opinion is as good as your opinion type
thing I think the last guy most likely gave a wrong opinion because he
didn't bother to check what we knew about Ardi against what we knew about
energy use in Chimps when they walked/ran and bipedal locomotion in
general.
[/quote:db0724561b]
I don't doubt all that, but if hominids weren't competing directly in
the same areas
initially (cut off for some unknown reason), then slight differences
in K/W vs bipedalism
wouldn't have mattered. After all, it took us a long time to take over
the planet, leaving
chimps and gorillas to sweat it out in the rain forests on the verge
of extinction.
If the great forests hadn't disappeared, we may have ended up barking
up the wrong tree.
______________________________________________________________________________________________________________________________________-
Could be but there were always some open areas and populations always push
up against their limits. Chimps do it now when given the chance and Ardi
would have been doing it then. Drought or no drought I can see these animals
becoming adapted to more open landscapes in a few million years. I don't
think the entire Sahara was ever a rainforest. In fact just because the
locals were living in forest doesn't mean they weren't making a go of it in
rather more open locations elsewhere or at least trying to with selection
doing its thing.
I'm going to add that I think you need to go back at least a million years
before Ardi to find the LCA of humans and chimps. Even if Ardi walked on all
fours in the trees the evidence is just to good that a healthy animal
wouldn't have done it on the ground. If you don't do something there is no
selection for doing it better so I can't see them ever becoming knuckle
walkers.
I'm still a little puzzeld how that chimp X chromosome managed to jump the
species barrior but if it did it did. |
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| deowll... |
| Posted: Tue Oct 13, 2009 12:20 pm |
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Guest
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<caldervangogh at (no spam) gmail.com> wrote in message
news:6f910830-0283-454e-8439-b127f59066b5 at (no spam) j19g2000yqk.googlegroups.com...
On Oct 10, 5:55 am, Gerrit Hanenburg <g.hanenb... at (no spam) inter.nl.nomail.net>
wrote:
[quote:dcc86a83db]One week after the publication we've been waiting for for 15 years
this group is awfully silent on Ardipithecus
[/quote:dcc86a83db]
A mere week ago, I was ducking out of this group out of sheer boredom
until "something interesting happens." Ha! Jokes on me, as we say in
the USA.
[quote:dcc86a83db], while it should be abuzz
about its implications. Have we become so numb by years of acrimonious
debate about AAT and such?
[/quote:dcc86a83db]
yes.
[quote:dcc86a83db]Such a shame.
Anyway, some implications of Ardipithecus:
- Death of the chimpanzee referential model. The chimpanzee is not a
living fossil but is derived in several aspects, and the CLCA was not
a chimpanzee. Early hominids did not compete with chimpanzees.
[/quote:dcc86a83db]
Big shake up; now what?!? <smile> I am reminded of two recent
papers.
One paper pointing out that human hair and/or chimp hair is not strong
enough to hold an infant in the upright posture. That is, the infant
proto-human would have to be carried instead of cling to his or her
mother. So, we must assume that Ardi carried her child! Why could
this not be one of the major factors in our survival, and in the
selection operating in this particular adaptive plateau?
The second paper concerned occasional "interbreeding" between our
emerging species and the chimps about 5mya. We may have had the CLCA
at, say, 7 mya, but then had contact at say, 5 mya, and that skews the
DNA dating. So, in addition to the loss of the chimp as a model, Ardi
seems to indicate that we need more time to evolve away from the CLCA
into the Ardi form.
What is your take on knucklewalking evolving twice.
The chimp model is dead. Wow. It had been under suspicion but was
all we had. Can we assume that Ardi has in common "nesting in trees"
every night, which gorillas also do?
++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Normal chimps nest in trees. Giant chimps sometimes nest on the ground the
big fellows, gorillas, as adults not so much.
Ardi are about the same size as a chimp with smaller canines that didn't
self sharpen. The local population included leopards. Ardi either spent the
night in trees or got eaten. How they dealt with leopards on the ground
during the day time is open to debate but I don't think they relied
exclusively on running away while screaming loudly. That just means the
hindmost gets eaten.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[quote:dcc86a83db]
- Death of the savanna model with regard to the origin of bipedalism.
[/quote:dcc86a83db]
good.
________________________________________________________
However it got better as time passed and populations moved into more open
regions.
__________________________________________________________
[quote:dcc86a83db]However, the habitat of Ardipithecus is reconstructed as woodland.
Woodland is already an environmental grade between closed-canopy
forest and more open environments. The Aramis environment does have a
grassy component and the isotopic data from Ardipithecus teeth signals
a C4 component of the diet between 10-25%.
More open environments are still proposed for the later adaptive
plateaus of Australopithecus and Homo.
- Four adaptive plateaus are now distinguished with regard to hominid
origins and subsequent evolution:
1) CLCA (last common ancestor of chimpanzees and humans; palmigrade
arborealist, dimorphic canines, forest frugivore/omnivore).
[/quote:dcc86a83db]
?nesting in trees?
?some tool use?
?propensity to have "culture"?
[quote:dcc86a83db]2) Ardipithecus (partially arboreal, facultative biped, feminized
canine, woodland omnivore). This adaptive plateau is newly proposed.
[/quote:dcc86a83db]
This is wonderful, to have a whole new plateau to study.
Although the authors of these papers makes a good argument for
reproduction & feminized canines, and I do not doubt those parts I
have read, I must ask what other factors may have lead to this
reduction. Change in diet, for example?
regards
calder
_______________________________________________________
Maybe some male found out that a good stout stick up along side of the head
trumped even the best canines and keep you far enough away you didn't get
bit.
_____________________________________________________________________________
[quote:dcc86a83db]3) Australopithecus (striding terrestrial biped, postcanine
megadontia, Pan-African, wide niche).
4) Homo (enlarged brain, dentognathic reduction, technology reliant,
Old World range).
- Ardipithecus is on the hominid branch of the phylogenetic tree. It
shares several derived craniodental and postcranial characters with
later hominids (e.g. advanced cranial base flexion, anterior position
of basion).
- Ardipithecus represents an adaptive plateau with bipedality on the
ground but also retaining significant arboreal capability. If
Sahelanthropus also belongs here the implication is that this
"compromise" arboreal/terrestrial adaptive plateau lasted for several
million years (c. 7 mya - 4.4 mya).
Gerrit
[/quote:dcc86a83db]
_______________________________________________________________
And most likely included several significantly different
populations/species. |
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| RichTravsky... |
| Posted: Sun Oct 25, 2009 11:40 pm |
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deowll wrote:
[quote]...
I tried to check out a web site that is supposed to show ape skeletons
including selected parts in motion but the thing didn't work for me.
[/quote]
What was the link? |
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| RichTravsky... |
| Posted: Sun Nov 01, 2009 10:10 pm |
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Guest
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deowll wrote:
[quote]...
I tried to check out a web site that is supposed to show ape skeletons
including selected parts in motion but the thing didn't work for me.
[/quote]
What was the link? |
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