Re: Bipedalism in different substrates

From: Paul Crowley (slkwuoiutiuytciuyik_at_slkjlskjoioue.com)
Date: 06/23/04 

Date: Wed, 23 Jun 2004 10:09:03 +0100

"J Moore" <anthrosciguy@yahoo.com> wrote in message news:Vf1Cc.851255$oR5.740778@pd7tw3no...

> Pauline M Ross <pmross@ross-software.co.uk> wrote in message
> > No, that isn't at all what I'm asking - quite the reverse. I'm saying
> > that every species has the body shape and size which best suits it for
> > its particular way of life, taking into account diet, climate and what
> > else lives in the neighbourhood. Naturally they vary widely. But
> > species with a similar way of life tend to have a similar body shape.
> > The interesting question is why some are different.
[..]
> > And even if we say that elephants and rhinos lost their fur because of
> > the heat-dumping resulting from their size, that still leaves the
> > problem of pigs and great apes (especially humans); why do you think
> > they lost (or partially lost) their fur?

> First, on pigs: remember that one, and only one, wild pig has little body
> hair (and it's one of two wild pig species that takes to water a lot, the
> other being very hairy, so the "it's aquatic" argument doesn't hold up
> well). Domestic pigs are not a good example of a "hairless" mammal, any
> more than other domestic animals are, such as some chihuahuas or hairless
> cats -- they were bred for that feature.
>
> You've got a couple other questions there, and I doubt I'll get a really
> good, thorough post on them, but here goes with a few points. I don't have
> a good, offhand response to the question of how an animal gets to be really
> big through its evolutionary history. About being predator-prone, though.
> One point often forgotten is that defense against predators often, with many
> animals, involves offensive behavior, even with relatively small potential
> prey versus larger predators. This is also how herding can help with
> animals which are somewhat big if not really large. In fact, even with
> solitary animals, this is done; counterattack is often enough an effective
> strategy (although almost completely ineffective against certain types of
> predators, such as crocodiles). Giantism has been in the past something
> which is/was not uncommon at least (many presentday species had much larger
> relatives in the ancient past -- sloths, bison, bears, crocodiles).
> Interestingly enough I think (could be wrong) that presentday African
> elephants are the largest elephants ever;

Not so. See:
http://news.bbc.co.uk/2/hi/uk_news/england/kent/3821527.stm

> I think the business about apes having less hair than other primates is
> interesting and rarely addressed.

No one had posed this question. The one
Pauline is (and the rest of us are) trying to
consider is why humans, and other species,
lack hair, when the standard mammalian
pattern is to have plenty of it.

> Now there's a good reason why this sort
> of thing is rarely addressed, and that's because we haven't been able to see
> any means of proving a reason, so we end up with essentially cocktail party
> conversation instead of science.

Maybe so, but that's strictly a reflection
(a) on the calibre of those taking part in the
discussion, and (b) on the horror with which
PA people are taught to regard any kind of
wider question, or one which does not involve
measuring something taken from the ground.

There are often only a limited number of
possible answers to this kind of question.
We are dealing with very small range of
solutions to the problems an endothermic
prey animal faces in the tropics, and the
number of variables is minimal. In any decent
science, this would be an introductory exercise
for students new to the subject. -- yet, in fact,
graduates are trained NOT to even think
about it.

> It's possible that things like the recent
> idea of looking at species of lice and their genetic history might help
> solve some of the questions, but it's still pretty early to tell if that
> really provides even the "when" answer the researchers hope it does/will.
> "How" and "why" answers are even more elusive. In apes we definitely see wh
> at seems to be a progression with lessened body hair, and this is one of the
> things that lead us in the past to make those ladders of evolutionary
> progress with us at the pinnacle, since the progression of that and other
> features happens to make a sort of pyramid with us at the top (where,
> naturally, we belong, according to most of our old philosophising, and that
> certainly helped that idea along). But I don't think anyone has a good idea
> why apes show this progression -- it could be size, as the apes tend to be
> on the large end of the primate size scale.
>
> As for humans specifically,

In fact, it's _worse_ than what I say above,
as we see from the rhetorical trick you are
currently employing. Humans are WAY
off any scale based on other primates, or on
other apes. The first step in any science is
to learn how to recognise reality. PA seems
to have evolved all manner of techniques
to ignore 'unpleasant' or 'inconvenient' facts.

> we do see rather obvious signs that our body
> hair features indicate a sexually selected feature.

And this is the pits. 'Sexual selection' is the
first refuge of bad scientist. It has the great
'virtue' of being non-disprovable. As a
scientific argument, it is next to worthless.

> There is the
> differences between people in different areas, differences between the
> sexes, differences during our lifespan, with the most dramatic differences
> happening between the sexes at puberty and continuing through the fertile
> stages of our lives. This screams out sexual selection

No, it does not. Nakedness is supposed to
be attractive to the opposite sex? Yes? But
at puberty we get MORE hair. Makes sense?
In fact, almost every aspect of human hair,
and its development during life, screams out
'NOT sexual selection'.

> (by contrast, a
> feature due to natural selection from a lifestyle that all members of the
> species shared would not tend to have such dramatic sex and lifespan
> differences).

The differences between the sexes --
as regards hair -- are trivial, especially
for humans adapted to the tropics.

> Coupled with this is the soemwhat related features of our
> sebaeceous glands. There is also a large difference between male and
> female humans in the number of their sebaeceous glands. Males have a lot
> more of them -- as they do apocrine glands, which are also used as a sexual
> "lure" -- and complimenting this, females have better scent receptors. And
> these sweat glands also become most active at puberty and after. It's also
> related to hair, since these sebaeceous glands tend to be most prevalent in
> those spots where body hair is present, where the scent can be more
> effectively spread because the hair helps -- this is also something seen in
> other animals, including primates, with scent glands.

That's why adolescents go around smelling
each other. And it's why the smells of the
various members of the opposite sex are
always the chief topic of conversation.
It's why -- in all languages -- we have such
a rich vocabulary on the subject.

> There may well be some other reasons for the differences between apes and
> monkeys, and between humans and our ape relatives, but I don't see, at
> present, a means of testing these, so they aren't really very effective as
> science. It's possible that we can, at some point, figure out how to test
> these ideas (figuring out when the changes actually occurred might help) but
> until then they remain interesting speculations. But we can see sexual
> selection written all over our presentday condition when it comes to our
> hair.

Utter and total bull***. Crap like this
could only become common in a discipline
where critical questioning was encouraged
to about the same extent as in schools of
Moslem theology.

Paul.

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