Re: Bipedalism in different substrates

From: Rick Wagler (taxidea3_at_shaw.ca)
Date: 08/23/04 

Date: Mon, 23 Aug 2004 05:28:23 GMT

"Algis Kuliukas" <algis@RiverApes.com> wrote in message
news:77a70442.0408221930.69fe0b53@posting.google.com...
> "Rick Wagler" <taxidea3@shaw.ca> wrote in message
news:<3dJVc.164775$M95.102748@pd7tw1no>...
> > "Algis Kuliukas" <algis@RiverApes.com> wrote in message
> > news:77a70442.0408200142.5fd12a42@posting.google.com...
>
> > > Safer: Even in depths up to waist deep it is safer to wade than to
> > > swim if the water is, you know, moving. (Flowing rivers, coastal
> > > waves, tides etc) In depths deeper than waist deep it could still be
> > > argued that it's safer to wade if you can because at least then you
> > > can keep track of the depth of the water you're in and see if you are
> > > getting out of your depth.
> >
> > Safety is not an issue. Animals are endlessly ambitious and
> > are without fear. Developing bipedalism as a means of guaging
> > depth makes no sense. Why is depth an issue for a swimmer?
> > If it is a non-swimmer what possible reason has it to be in water
> > of a hazardous depth so often as to necessitate such an extreme
> > evolutionary response? As for being in currents so strong as to
> > be impossible to swim against being bipedal is not really going
> > to be of much use. Useful for what? Maybe you can dig your
> > feet in and hold your position and not expend the energy that
> > swimming involves but what behaviour or activity would necessitate
> > such a thing to the extent that it would activly select for bipedal
> > behaviour? And wouldn't being quadrupedal in such a circumstance
> > be more efficacious? As I said animals are without fear but they
> > are risk-averse. Fear of getting in too deep is not an issue if
> > you can swim. There is no 'too deep'. But plunging into a
> > powerful current -why???
>
> 'Animals are .... without fear' - are you serious? Apes are poor
> swimmers therefore they probably have a real and justifiable fear of
> water.

Of course. Any animal 'fears' hazards and the unfamiliar. But for its
normal routine of activities? Fear of heights in an orang-utan? Not in the
sense that such fears exist in humans where we can abstractly envision
hazards and consequences.

That's probably why they *do* wade bipedally - in Conkuati
> chimps, even when the water is up to their shoulders.
>
Are you saying these chimps can swim? Or are not so foolish as
to plunge in over their heads? All animals are able to assess risks
of this sort.

> Fear of getting in too deep might not be an issue if you are as
> aquatic as a seal, but for those mammalian species (like hominoidae)
> which are not very adept it is a real issue. But you just wish it away
> with a flick of your wrist as if it did not exist.
>
Again *if* your ape can swim it will not develop bipedal wading to
avoid swimming. If it can't swim then it will wade bipedally simply as
part of a suite of bipedal behaviours. Your argument is that bipedalism
is a **response** to the need to wade is it not?.

> > > I know that swimming is faster than wading at depths greater than
> > > waist deep but there's more to it than just speed, right?
> > >
> > Sure. But the point remains that swimming is the overwhelming
> > choice when it comes to dealing with water. This ape of yours
> > augments it with bipedalism. Why? An ape will go bipedal in
> > these circumstances - sometimes - because it can not because
> > it must.
>
> If the animal is small and/or the water is deep then, yes, swimming is
> the usual response but if relatively large apes find themselves in
> strips of woodland surrounded by relatively shallow standing water,
> this is not the case, right?

Sure but so what. Shallow water -relative to the size of the animal - will
evice wading behaviour in all animals. What point are you trying to make?
>
> > > Swimming is bound to be a riskier mode of locomotion than not
> > > swimming, agreed?
> >
> > No.
>
> NO? - What is the point of discussing these issues if you are so
> bleeding stubborn you cannot even concede such a point? For a
> terrestrial animal swimming *must* be riskier than not swimming. I
> know all people are capable of twisting whatever evidence is presented
> to them into a form that meets with their own pre-conceived ideas so
> as to delude themselves that they are right, but you aquasceptics are
> particularly adept at it.
>
Look, Algis, the issue is developing bipedal wading as an alternative
to swimming. At depths where wading is an option to swiming the
hazards of swimming are nil for all practical purposes. The unfortunate
children you refer to are not a counterargument to the general point.

> > Swimming is riskier only because it allows an
> > animal to ignore depth and, sure, on occasion this will
> > lead to disaster but so often as to, on at least one
> > occasion, lead to an extraordinary selection of
> > characters to largely dispense with the need to swim
> > or to chain this animal to relatively shallow depths?
>
> Apes, generally, are poor swimmers. So - as you guys keep reminding me
> - are we. Therefore swimming is riskier than not swimming for a
> hominoidae, right?
>
Re- read what I wrote immediately above. Are you claiming
bipedal wading developed to obviate the need to swim or
aren't you?

> > This is an extraordianary claim and you should at least
> > try to back it up. If all you are saying is that bipedal
> > wading can, at times, be the preferred option I can
> > certainly agree with this but you are claiming much,
> > much more without, seemingly, realizing that you are
> > doing so.
>
> So - arguing that swimming is riskier than not swimming in hominoidae
> is an "extraordinary claim"? Blimey.
>
No arguing that bipedal wading developed as an alternative is. You
simply have to read more carefully.

> See how even this first, simple logical step on my list has to be
> challenged vehemently? Can't you see how this rabid anti-AAHism has
> left you devoid of all common sense?
>
Swimming is riskier than not swimming. Climbing is riskier
than not climbing. Running is riskier than not running. See
where this is going? If you have an ape that spends so much
time in the water that all major differences between humans
and modern apes can be explained by it this animal will be
adept at being in the water and this will include swimming.
Or are you back to the non-swimming, water-loving ape? There
is risk in everything any animal does. If swimming was so extraordinarily
dangerous a proposition this ape will behave like modern apes
and largely avoid the water except where it is shallow enough to
let a facultative biped exercise the option. In all the hundreds of
post you have made you have yet to lay out exactly why
more wading will enhance bipedalism.

> > > So, if a hominin has to cross a stretch of water and
> > > it can avoid swimming by wading then it is more likely to survive.
> > > Still with me?
> >
> > Nope.
>
> What a surprise. No, any argument that claims that water played *any*
> specific role in human evolution must be resisted at all costs. Such
> fanaticism. It's so peculiar.

To repeat... wading through shallow areas in order to avoid
swimming through deep areas will reduce risk a bit. Wading
to avoid swimming in areas where both are possible will
not increase survivability in any significant way. Just what
is the rate of drowning in accomplished swimmers anyway?

>
> > If it can swim then it is not going to drown in
> > wading depths.
>
> But apes are not very good swimmers, right? Even humans are not very
> good swimmers either, but we're better than apes.
>
At wading depths you don't have to be very good.

> > If it gets too deep it must swim or turn
> > back. So what is achieved. At depths where it is
> > possible to both swim and wade the risk of swimming
> > is for all practical purposes nil.
>
> Practically nil is still greater than nil. Over an evolutionary
> timescale this would get translated into meaningful selection.

Nonsense. For all practical purposes means that the occasional
freak accident will not affect the survivability of the species and
will not generate selective pressure.

It is
> not black and white. Some risk is greater than no risk. Chimps and
> children have been known to drown in shallow water. Blimey, I thought
> that was one of you guys' key arguments against the AAH. If our
> ancestors were exposed to that kind of risk more than their's (chimps)
> why is it so astonishing that we would evolve modest traits to help a
> little in those areas?
>
Because your alternative is no help. Especially since you are almost
certainly dealing with a facultative biped. But you avoid dealing with
that in order to argue some phantom reason to evolve bipedal wading.
There is no evolution of bipedal wading in the LCA. It can already
do that and probably had this option available to it for millions of
years. You got to flesh out your more wading > obligate bipedalism.

> > That's why people learn to
> > swim in the shallow end. It can only avoid swimming by
> > wading by never going to those places that only swimming
> > can take you. Your image of the super cautious wading ape
> > just makes no sense. If this animal is going to exploit aquatic
> > habitats to the degree that this activity led to the selection
> > of every major anatomical and physiological difference
> > between humans and modern apes then Hagstrom's
> > merpeople scenario is the much more sensible speculation.
> > Really, Algis, you should have the courage of your convictions.
>
> Again - this notion that in order for the selection to be real it has
> to be extreme - why? I ask again, what selective pressures, in a
> single generation, drove encephalisation? It clearly happenned but can
> you define, with any precision, exactly how a slightly bigger brained
> individual had selective benefit over a slightly smaller brained
> individual in any given lifetime? Come on - think about it. Apply the
> same level of scepticism to that as you do to the wading idea. Now see
> how the wading idea, in comparison, is so easy-peasy and clear cut?
> No, I don't suppose you will see it that way.

What drove encephalisation? Improved diet. Did this 'drive'
encephalisation or did it just open up possibilities. See the
difference. Don't let Verhaegen's hyper-adaptationism foul
you up.
>
> > Therefore traits which make hominins better waders are
> > > clearly going to be selected for if individuals have to cross
> > > stretches of water, even only ocasionally.
> > >
> > What makes a better wader? When you hit the water just
> > keep going. A biped is no better or worse a wader than
> > a quadruped
>
> What makes a better wader? Duh. The same kind of things that make for
> better quadrupeds, bipedal walkers, swimmers, flyers, burrowers: more
> efficiency, more speed, more power, more stability - you know....
> better.
>
So what produces a better wader? How is an obligate biped
a better wader than a quadruped. All animals --okay, maybe
not snakes - do just fine as waders.

> A biped is no better or worse a wader than a quadruped? But which
> quadrupedal mammals wade bipedally? Oh - its just the apes. Just a
> coincidence that, eh, Rick?
>
Your logic centres shorting out again? This makes no sense.
To repeat why is a biped a better wader than a quadruped?

> Bipedal wading in waist deep water imposes exactly the same weight
> bearing strains on the lower back and pelvis - that would clearly act
> as forces of selection - as does terrestrial bipedalism.

But the characteristic features of bipedalism in humans are
not in evidence while wading. You do not wade the same
way as you walk at a brisk pace. Go to a pool and see for
yourself

It imposes
> slightly less weight bearing stresses on the knees but in knee depth
> water (where apes still tend to move bipedally) those weight bearing
> stresses would again be nearly identical to terrestrial bipedalism. If
> you can accept that terrestrial bipeds are better at bipedal
> locomotion on land than a quadruped (can you even do that, Rick? - I
> expect that you'd have to deny it too - can't be seen agreeing with a
> AAT net loon on anything can we - you'd probably get expelled from the
> party!), why is it so very difficult for you to accept that bipedalism
> in water would have any effect at all?

Again why is bipedalism a superiour form of wading?
What impels a quadruped to wade bipedally? If terrestrial bipeds
are better at bipedal locomotion than quadrupeds??? This
is gibberish. I can't discern what point you're trying to make.

Don't tell me... - 'It just is.
> It's water, right? And water played no part in our evolution because
> that's what I've been taught and that's what we all think here, so
> *** off with your AAR!'
>
> > > Which part of that logic is wrong?
> > >
> > Your premises...which is to say grant me my premises and
> > I can make an elephant fly....
>
> Oh sure, it's *me* whose doing the twisting, right. Note that you
> could not even accept my first premise that swimming was riskier than
> not swimming.
>
In the circumstances of shllow, wading depths yes. Even deep
water swimming will not be so hazardous as to affect populations
in a major way or else the animal is just not going to do it. We
dryapers use the argument of limited human aquaticism as an
argument that life in the water did not play much of a role in
our evolution. You use it as an argument that we must have become
in some completely undefined way better waders. I guess that's
what it comes down to.

> > > I know that you must find fault with it somwhere, otherwise you'd have
> > > to disagree with your pal NAS and we can't have disagreement in the
> > > ranks of the 'slightly more open woodland than chimp habitats but
> > > slightly less open than savannah ecotone' club.
> > >
> > Since Norm and Jason and Bob and Mike and --GOOD GOD
> > ALMIGHTY!!! ....Paul???? make so much more sense when
> > dealing with you why would I disagree.
>
> Oh well, if this is the criterion on which you judge whether a
> hypothesis is valid or not, no wonder.
>
Consider the arguments and go with those put forth by
people who are well grounded in PA in particualar and
evolutionary biology in general. Of course since you use
MV as primary source *that* option is not open to you...

> > As an aside where are you getting this Med-Tethys shoreline
> > business re hominoid apes??
>
> Oreopithecus - perhaps contemporaneous with the LCA, if not on the
> same line as Hominins.
>
It's not.

> Paleogeography of Miocene ape sites (Several European locations.)
>
Some certainly. But Miocene hominoids are very widespread. There
is no basis for saying the Med-Tethys shoreline was a particualar
hotbed of Miocene Apedom.

> Paleogeography of the Me/Tethys coastaline around the mid-late
> Miocene.
>
Which is the predominant habitat of apes??

> It's called putting two and two together: African Hominoidae are
> likely to have lived in such coastal habitats.
>
African apes lived all over Africa. You have absolutely no
basis for asserting this. I keep telling you. Watch out for
Verhaegen. The man's a friggin tar-baby.

Rick Wagler

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