Re: A *Dry* Discussion About The Origin Of Bipedalism


rmacfarl wrote:
> mclark wrote:
> > "rmacfarl" <rmacfarl@xxxxxxxxxxxxxxxx> wrote in message
> > news:1125114048.973601.63410@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> > > Mclark,
> > >
> > > I'm interested in this idea you've previously floated about the origin
> > > of bipedalism being linked to arboreal origins. I know it's been
> > > brought up usually in opposition to all that wet theorising, but I'd
> > > like to hear you expound on your idea bit further. Care to have a
> > > crack?
> >
> > Well, if you ask me, I think this whole 90% twist from
> > horizontal to vertical is a response to the problem of moving
> > an increasingly large body through the branches of trees.
> > I think I had this conversation with Pauline a while back
> > and if I recall (without a search), I think that I said something
> > about the nature of trees (they have a vertical trunk, in most
> > cases, branches angle off from this trunk at increasing angles
> > as they move away from the trunk and that useful resources
> > are usually found toward the termination of these branches),
> > and that larger bodies would be restricted by certain physical
> > laws from employing the normal monkey modes of travel.
> > As these increasingly large apes were restricted toward the center
> > of the tree, they were increasingly relegated to vertical climbing
> > (the vertical trunk), prevented from brachiating (more central
> > branches are larger). That leaves them with the upper surfaces
> > of larger branches. Foraging, and supplementing their balance
> > with their hands by grasping nearby branches, these apes would
> > find themselves with their feet both *on the ground* and acting as the
> > sole interface with the substrate. Add this to the fact that running
> > along the tops of branches is actually *more* stable that walking,
> > and the observation that *sitting* adds its own set of variables
> > to the mix (changes to the lower spine) and you have a certain
> > inevitability to the notion that those apes thus pre-adapted to
> > bipedalism would find themselves moving bipedally when
> > ~whatever~ moved them to the ground.
>
> Hmm [grimace]. My experience of climbing is that when you have to try
> to get out to the further edges of a thin branch, the opposite to what
> you posit above applies. I prefer to get on all fours & grip on to the
> branch with my legs while I gingerly stretch out along a section that
> feels like it's about to give way under me.

What are your primary references for this?

>
> What I've seen of chimps suggest a similar approach. I have a mental
> image of males hunting by climbing outward on all fours toward a
> trapped monkey, for example.

You have to be retarded to think this has any relevance to hominid
evolution.

>
> Also of course, the actual brachiating ape adaption is for suspense
> foraging - hanging under branch, cf. orangutans, as opposed to Old
> World monkeys that run on all fours along the top of branches.
>
> All in all when you're up in the treetops I'd feel more secure with 3
> or 4 points of contact when branch-walking than with 1 or 2. Hence I
> can't say I find this scenario convincing.
>
> Just my opinion, of course.

Anthrodimwit

>
> > "Whatever" could be
> > anything that would initiate the move from tree to terrestrial --
> > drying and cooling, which would disperse the trees, a mere
> > local preference for a food source on the ground, a population
> > shift in geography, etc.
> >
> > I think R.H Crompton has at least intimated much the same.
> > Check this out:
> > http://www.liv.ac.uk/premog/premog-pubs.htm
>
> Which of the papers was the specific comment in, do you recall?

Like it matters.

>
> >
> > > [Watery types need not apply...]
>
> Nor other loons - i.e. Jimbo & Paulie...
>
> Ross Macfarlane

.

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