The fact that chimpanzees & gorillas both walk on their knuckles has long been cited as evidence that we all evolved from a common ancestor that knuckle-walked, and that we alone “progressed” to walking on 2 legs. However, research indicates that “KWing was independently acquired after divergence of the Pan & Gorilla Lineages.” [i] Others have long argued that KWking did not represent an intermediate stage preceding BPism, but was rather a reversion toward QPism in large-bodied apes specialized for brachiation. [ii] In fact, KWing is much better developed in gorillas, and quite different from chimpanzees, [iii] and the LCA of Homo & Pan could not have been a KWer, since humans show no sign of this behaviour: when we lean on a table, we use the flats of our hands; in males, the middle hand phalanges are hairy compared to apes where they are naked; our infants learn to crawl with palms to the floor, [iv] and even, in rare instances of humans who habitually walk on all 4s, they do so with their palms to the ground. [v] Conversely, some of the australopiths had KWing features: “the curvature & the cross-section of L.40-19[Paranthropus bosei] are reminiscent of KWers (Howell & Wood 1974). Even Leakey 1971 claimed: “the Rudolf australopithecines, in fact, may have been close to the ‘KWer’ condition, not unlike the extant African apes.” [vi]
> In their paper "Independent evolution of knuckle-walking in African apes shows that humans did not evolve from a knuckle-walking ancestor", Kivell & Schmitt write: “… variation among African ape wrist morphology can be clearly explained if we accept the likely independent evolution of 2 fundamentally different bio-mechanical modes of KWing: an extended wrist posture in an arboreal environment (Pan) vs a neutral, columnar hand posture in a terrestrial environment (Gorilla). The presence of purported KWing features in the hominin wrist can thus be viewed as evidence of arboreality, not terrestriality, and provide evidence that human BPism evolved from a more arboreal ancestor occupying the ecological niche common to all living apes.”[vii]
> Orangutans (Pongo) are sometimes also cited as evidence that we all descended from a KWing ancestor, but orangutans differ from the African apes in that they tend to support their weight on the lateral sides of their fists rather than their knuckles, suggesting that they too evolved this in parallel. Others agree that it is far more likely that we all (Pongo, Gorilla, Pan & Homo) evolved from an orthograde arboreal ape towards a BP terrestrial ape, and then only Pongo, Gorilla & Pan reverted, at different times, in different places, towards a KWing (or in the case of Pongo, fist-walking) mode of locomotion: “If the traditional idea that hominins passed through a terrestrial ‘KWing’ phase is correct, not only does it have to be explained how a QP gait typified by flexed postures of the hindlimb could have pre-adapted the body for the hominin acquisition of straight-legged erect BPity, but we would have to accept a transition from stem-hominoid pronogrady to crown hominoid orthogrady, back again to pronogrady in the African apes, and then back to orthogrady in hominins. … Derivation of habitual terrestrial BPity from arboreal hand-assisted bipedality requires fewer transitions, and is also kinematically & kinetically more parsimonious.”[viii]
> ------------------------------
> [i] Simpson, S.W., Latimer, B. and Lovejoy, C.O. (2018), Why Do Knuckle‐Walking African Apes Knuckle‐Walk?. Anat. Rec., 301: 496-514. https://doi.org/10.1002/ar.23743
> [ii] Fossil apes and human evolution Sergio Almécija, Ashley S. Hammond, Nathan E. Thompson, Kelsey D. Pugh, Salvador Moyà-Solà and David M. Alba, DOI: 10.1126/science.abb4363. Science 372 (6542), eabb4363
> [iii] Inouye S.E., 1992.Ontogeny of knuckle-walking hand postures in African apes. American Journal of Physical Anthropology, Supplement 14: 55.
> [iv] Schultz A.H., 1936.Characters common to higher primates and characters specific for man. Quarternary Review of Biology, 11: 259–283 and 425–455.
> [v] Ledford, H. Mutations may make humans walk on all fours. Nature (2008). https://doi.org/10.1038/news.2008.868 https://www.nature.com/articles/news.2008.868
> [vi] Verhaegen, M.J.B. Australopithecines: Ancestors of the African Apes?.. Hum. Evol. 9, 121–139 (1994). https://doi.org/10.1007/BF02437259
> [vii] Tracy L. Kivell, Daniel Schmitt, Independent evolution of knuckle-walking in African apes shows that humans did not evolve from a knuckle-walking ancestor, Proceedings of the National Academy of Sciences Aug 2009, 106 (34) 14241-14246; DOI: 10.1073/pnas.0901280106
> [viii] Crompton RH, Vereecke EE, Thorpe SK. Locomotion and posture from the common hominoid ancestor to fully modern hominins, with special reference to the last common panin/hominin ancestor. J Anat. 2008 Apr;212(4):501-43.. doi: 10.1111/j.1469-7580.2008.00870.x. Erratum in: J Anat. 2008 May;212(5):703. PMID: 18380868; PMCID: PMC2409101.
>
(Francesca at aat@groups.io)

littor...@gmail.com wrote:

> The fact that chimpanzees & gorillas both walk on their knuckles has long been cited as evidence that we all evolved
> from a common ancestor that knuckle-walked,

I have never seen that claimed. At all.

And both seem to have evolved well past bipedalism, so both appear to have
"Evolved" knuckle walking from upright walking.

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Op donderdag 8 juli 2021 om 09:55:29 UTC+2 schreef I Envy JTEM:

> > The fact that chimpanzees & gorillas both walk on their knuckles has long been cited as evidence that we all evolved
> > from a common ancestor that knuckle-walked,

> I have never seen that claimed. At all.

It's the traditional view (wrong, of course):
if Pan & Gorilla KWing were the same, it had been logical to think that the Pan-Gorilla LCA already KWed, but Pan & Gorilla KWing arge quite different, and Homo does not KW, so Gorilla & pan KWing evolved in parallel.

> And both seem to have evolved well past bipedalism, so both appear to have
> "Evolved" knuckle walking from upright walking.

No, no, not form upright walking, but from upright climbing-wading,
google "aquarboreal".

littor...@gmail.com wrote:

> It's the traditional view (wrong, of course):
> if Pan & Gorilla KWing were the same, it had been logical to think that the Pan-Gorilla LCA already KWed

There's nothing logical in leaping to such assumptions.

It's a practice that has been ruining things since Darwin. He wasn't a scientist. He argued
what passed for logic in his mind and he set by science by two decades! Yes, it took that
long for the English speaking world to rediscover Mendel and actual science, after Darwin
buried it all.

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Op vrijdag 9 juli 2021 om 18:11:03 UTC+2 schreef I Envy JTEM:

> > It's the traditional view (wrong, of course):
> > if Pan & Gorilla KWing were the same, it had been logical to think that the Pan-Gorilla LCA already KWed.

> There's nothing logical in leaping to such assumptions.

There's everything logical in this:
if P & G had the same KWing, the P/G (hence also the HP/G) LCA had already that KWing.

But P & G KWing are very different anatomically & ontogenetically, so the HPG-LCA probably did not yet KW.

Besides, we clearly showed that early hominoids were aquarboreal (google "aquarboreal"),
and KWing is not unexpected when aquarboreals revert to QPism:
KWing dimishes the distance between vertical & QPal with they height of the hands without the middle & distant phalanges vs palmigrady
(the main reason why they don't walk on their middle phalanges instead of on their fingertips is probably because fingertips are not strong enough).

littor...@gmail.com wrote:

> There's everything logical in this:

It's science. There is no room for fanciful leaps, even if mischaracterized as
logic.

It's science. Not logic, science.

First rule of evidence: It supports multiple conclusions. So is there any "Logic" is
cherry picking one and pretending it is "The" answer?

Of course not.

"But this one answer SEEMS more likely to me because..."

Science exists to eliminate the human element. bias, a priori assumptions...
the individual point of view.

What you're mislabelling as "Logic" is the antithesis to science.

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Op zaterdag 10 juli 2021 om 00:11:56 UTC+2 schreef I Envy JTEM:

> > There's everything logical in this:

> It's science. There is no room for fanciful leaps, even if mischaracterized as
> logic.

You are the fancy leaper.

littor...@gmail.com wrote:

> You are the fancy leaper.

No I'm not. I am very grounded in the evidence. This is why it was me
against talk.origins -- the entire group, not one person on my side --
back when I was arguing Neanderthal interbreeding. I'm the very last
person to be swayed by prevailing/popular views, the last person to
be drawn away from the evidence.

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Op zaterdag 10 juli 2021 om 18:55:11 UTC+2 schreef I Envy JTEM:

> > You are the fancy leaper.

> No I'm not. I am very grounded in the evidence.

:-DDD

littor...@gmail.com wrote:

[...]

Dude, you think citing yourself is evidence!

Again, i'm on record. Over in talk.origins I was arguing Neanderthal
interbreeding and the group -- the entire group -- was arguing that
it never happened. Then, as now, I tried very hard to argue the evidence,
while the group thought opinions (labelled "Conclusions") were facts.
Notably: The mtDNA "Evidence." I cited their own "Evidence" -- like the
Out of Africa/Eve 2 study that supposedly "Discovered" Mitochondrial
Eve, and how it was based on assumptions that ran counter to the
no-interbreeding assumptions. Put short: They couldn't BOTH be right!

If you assume [A] is correct to arrive at an answer in one study, then
assume [A] is false to arrive at a conclusion in another study, one of
those studies must be wrong. At least.

...in reality BOTH conclusions were wrong. There is no "Molecular
Clock," mtDNA is under selective pressures, and human interbreeding
is asymmetrical. So, neither study was right.

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