Re: human ancestors never passed through a knuckle-walking phase

On Aug 5, 2:18 am, "Paul Crowley"
<slkwuoiutiuytciu...@xxxxxxxxxxxxxxxxx> wrote:
"nickname" <alas_my_lo...@xxxxxxxxx> wrote in message

news:1186267544.711904.252810@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

The gorilla and chimp niches are (or were)
HUGE. An animal occupying them has
no good reason to change, and the size
of the population would have rendered
any substantial change very difficult.

I see that a new species of coelacanth has
been found off Indonesia -- quite separate
from its cousin off South Africa. That
taxon found its niche around 400 million
years ago, and has found no need to
change since.

The ecotype is stable there

Since no one has the remotest idea what it
is like, that's a pure guess.

No, if the ecotype changed, the species would change or vanish and be
replaced by one better fit for that new ecotype. The coelecanth has
found a stable niche in a stable ecotype, and mutations which might be
selected in a different ecotype are eliminated due to being less fit
than the standard model.

so the niche may endure, a taxon adapted
to that niche may endure as well. Inland habitat is far more variable,
due to climate (and other) changes.

It might have varied in size, but never
disappeared. In fact, it was always
probably thousands of square miles.
If it had fallend below that, many species
of trees and plants would have gone
extinct.

(Fossil and extant) Gibbons/siamangs and orangs lack traces of these
locking wrists?

Yes.

That some hominids knucklewalked is uncertain but quite possible.

Surely a definition of 'hominid' involves
the term 'biped'. (Although, confusion has
entered terminology -- some people here
use 'hominin'. But I hope you know what
I mean.)

I'm saying our ancestors did not knucklewalk.

No modern children pass through even a vestige of knucklewalking, yet
nearly all pass through a kneecrawling phase, for months (when not
kept bound-up in some cultures). No other biped does this, kangaroo,
gibbon, sifaka, penguin, etc. Only Homo sapien. Since we lack thick
padding on the knees (say comparable to gibbon rump pads), I presume
knee crawling evolved on soft strata, certainly not in trees or on
rough savanna ground or rocky caves.


Why are you saying this? Don't you
feel that you need a reason?

When they needed more
support than two legs, they a) used a walking stick like the Ndoki
gorilla did to cross water of unknown depth b) Walked palms and soles
down (steep terrain, cliffs) c) kneecrawled (mucky or sandy
substrate)

Why would anyone want to believe in
such a crazy theory? How did such
animals RUN?

There is rarely a need to run in water, muck or on cliffs. Human
ancestors ran bipedally, probably leaning forward with nose ahead of
pelvis, not so different from gibbon walking on the ground. Selection
for diving produced a more linear form, less ape-like.

What's wrong with having chimps as
ancestors?

LCA HP was by definition not a chimp, in the same way that you are not
your grandfather, you are his descendent.


Below is my brief version....

Among hominoids, only humans and gibbons are obligate bipeds on the
ground, both tail-less & airsac-less.

Gibbons are about as much 'obligate bipeds'
as we are 'obligate quadrupeds' when we are
crawling under tables.

Yes, precisely, the vestiges remain, knucklewalking doesn't.

I.e. such behaviour
is totally irrelevant to the life-style and the
occupation of a niche.

Chimps and gorillas have recently became more habitually terrestrial
(more open forest)

Pure nonsense. Why should 'more open
forest' exist where it did not before?

Ice Ages, etc.


and so adapted a makeshift kwalk quadrupedal gait,

There is nothing makeshift about knuckle-
walking. It is an excellent system for getting
(quadrupedal) speed on the ground while
maintaining powerful and flexible hands for
grasping (i.e. climbing trees) and for
manipulation.

Yet forest monkeys don't use it even .01% of the time. Why? Because
monkeys didn't lose their qpal ground habit, apes did.

after previously been bipedal like gibbons.

Ridiculous. Firstly, gibbons are not 'bipedal'
in any real sense. They do not live on the
ground and when finding themselves there,
get off it as fast as they can.

Always bipedally, unlike other apes. They completely lost qpal
behavior on the ground.

Secondly, you have not begun to understand
the adaptations necessary for true bipedalism.

How did these 'bipedal chimps' sleep in trees?

If you are referring to the LCA HP, no doubt they could climb trees
both for food and nest sleeping. The most bipedal of great apes the
bonobos sleep in tree nests.

How did they get around trees? How did the
females carry infants?

Probably the same as other apes, but were at coasts consuming seafoods
part-time as some monkeys do.

The LCA H-oid AFAICT had a combination of vertical climbing, wading
and semi-vertical floating (selected for enlarged laryngeal air sacs
and reduction of tail) and very primitive tree nesting began at
coastal or islanded population, during a "global" dry period.

Why propose such nonsense? What
evidence do you have that this is -- in
any way at all -- a viable life-style?

Because it answers the question, why are we different than apes. Food
collection in water, nearby trees for nesting and seasonal food,
presence of airsacs, loss of tail, former bipedalism etc.


Were the ancestors of this animal gibbon-
like?

No. Gibbons and great apes and humans derived from a coastal biped LCA
hominoid, thus the tail loss.


No
knucklewalking at that time. From there

What made this population so successful
that it was able to have so many kinds of
descendants?

There is a monitor lizard that specializes in eating croc eggs, it's
possible that the LCA H-oid also had this habit, as well as eating
turtle and bird eggs (all apes eat eggs). By reducing the viability of
crocs, coastal tidal wetlands would have been relatively safer for a
floating-wading-swimming hominoid.
Speciation was due to expansion along coasts and rivers over time,
with different adaptations to local environments eg. knucklewalking in
dryer areas.

And if it was THAT successful
how come there is nothing like it around today
(nor within historical times) ?

Homo sapiens took that niche when boats were developed. (I think that
is what wiped out the Neandertals later as well).

the various apes and apiths
were derived as the geoclimate got wetter inland, the population
expanded (highland forest gibbons, siamangs became more spiderlike
brachiators canopy specialists); spreading along coasts and inland
along coastal rivers-swamps-marshes (orangs, then gorillas).

You have no concept of ends and means.
You seem to think that you can invent any
kind of fantasy-world and fantasy-evolution
you wish.

Paul.

It's a lot of territory to cover so briefly. Tail-loss in H-oids due
to floating with filled airsacs inflated during shrieking. Homo losing
the air sacs due to back-float / diving at seashores. Chimps/gorillas/
orangs losing the ability to swim/float due to changed environment
away from tidal waters. Humans losing the separate hallux yet able to
climb coconut trees, in which a separate big toe is useless.

Homo from chimps? No chance.

.

Relevant Pages

  • Re: human ancestors never passed through a knuckle-walking phase
    ... gibbon, sifaka, penguin, etc. ... knee crawling evolved on soft strata, certainly not in trees or on ... monkeys didn't lose their qpal ground habit, apes did. ... the adaptations necessary for true bipedalism. ...
    (sci.anthropology.paleo)
  • Re: A *Dry* Discussion About The Origin Of Bipedalism
    ... >> of bipedalism being linked to arboreal origins. ... > an increasingly large body through the branches of trees. ... > about the nature of trees (they have a vertical trunk, ... > As these increasingly large apes were restricted toward the center ...
    (sci.anthropology.paleo)
  • Re: A *Dry* Discussion About The Origin Of Bipedalism
    ... >>> of bipedalism being linked to arboreal origins. ... >> an increasingly large body through the branches of trees. ... >> laws from employing the normal monkey modes of travel. ... >> As these increasingly large apes were restricted toward the center ...
    (sci.anthropology.paleo)
  • Re: Bipedalism in different substrates
    ... > You say 'similarly evolved' as if gibbons were obigate terrestrial ... water is *required* in the development of bipedalism. ... I have no problem seeing all apes stand in water. ...
    (sci.anthropology.paleo)
  • Re: A critique of the BBC aquatic ape programme and the transcript.
    ... >>> orthograde locomotion when the other apes mostly haven't? ... >>Well, from here, it looks like humans are the sole survivors ... but your thesis is that some form of bipedalism (ie orthograde ... food --leaves, fruits, colubus are found only in the trees. ...
    (sci.anthropology.paleo)