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Re: Adaptive Niche of Arc
Norman Sides (nas@crl.com)
22 Jun 1995 21:30:35 -0700
In article <60.1779.7295.0N1E772B@canrem.com>,
J. Moore <j#d#.moore@canrem.com> wrote:
>Na> How could natural selection favor abilities and behavioral
>Na> dispositions enabling people to create social systems of a complexity
>Na> and diversity far greater than any that their G&H ancestors needed to
>Na> cope with conditions they actually encountered? Why didn't evolution
>Na> just maintain the G&H status-quo? Or why didn't it simply produce some
>Na> more effective type of G&Hers?
>
>Well, this is in fact what seems to have been going on *throughout* human
>evolution, from early australopithecines to H.s.s.: producing hominids
>that are better at what they do than their ancestors were, and who do a
>better job of making an environment that works for them out of what they
>have available, making more different niches, particularly areas with
>vastly different climate, available for their use.
>
>Na> I do think, however, that a considerable
>Na> body of evidence supports the idea that they were restricted to a
>Na> particular adaptive niche (or a cluster of related niches?).
>
>Depends on how you define that. What could be said to be the "odd
>difference" about hominids is that long before the modern types, like
>H.s.s or even archaic H.s. and Neadertals, they had been making their
>G&H niche work in ever wider climatic conditions, which is a pretty
>remarkable thing really. We need to remember that hominids, like all
>organisms, *make their own environment*. (Plants, as one example, break
>up the soil they're in with their roots, which lets water in.) Richard
>Lewontin points out that all organisms create their environment out of
>what's around them in their reactions to what's useful, what they
>perceive or don't perceive (he points out, for instance, that gravity is
>completely unimportant to many organisms, even though for us it's a
>critically important and ubiquitous force), and so on. There are
>limits for each organism as to how far they can take this without
>gross physical change (which may or may not be forthcoming) that is
>larger than the amount of somatic change they can undergo. ("Fish gotta
>swim, birds gotta fly", although even those generalities have to be
>modified to fit the real world [much as the next line in the song has to
>be modified to fit the relaities of human sexuality ;)].) Physical
>change to fit local conditions limits options, and that's where hominids
>got lucky.
>
>Hominids, apparently uniquely among primates, happened to get around
>this through a set of "lucky breaks". Through the use of some improved
>tools, more steady and increased use of meat sources, increased stature,
>brain size, and possibly/probably such inventions as slings or other
>primitive containers and carriers, as well as ongoing innovations in
>social organization and communication, they became able, between 2 and
>1.5 million years ago, to use more climatically different areas, which
>dissolved barriers to travel and opened up to them one whole helluva lot
>of space.
>
>So I'd say your next statement is probably not completely accurate:
>
>Na> In this they were like all the creatures before them. It's the
>Na> moderns, not the archaics, who are anomolous in this respect.
>
>There are certainly other types of animals who cover this sort of
>ground, although generally, in mammals, with bodily changes (greater
>than somatic) that are greater than what we seem to see in erectus et
>al. These would be the various dogs, in which we have different species
>along the equator than we have in the temperate forests, although they
>seem to have a great deal of interbreeding ability among many of these
>types; horses (horses, zebras); pigs; etc. But hominids *are* odd among
>primates in this, and this started so long ago. Can we really say that
>this change, from say australopithecine to late erectus, is less of a
>dramatic change than from erectus to H.s.s.?
>
>I think you could make a case either way because the two cases can't
>really be compared. They're both pretty dramatic. It's much the same
>reason you always see people thinking their era is the fastest changing
>ever -- it's because they didn't live in the previous eras. The changes
>we see now, are they really so much greater or faster than the
>changes in our ancestors' world views when they realized they *weren't*
>at the center of the universe? Than the introduction to Europe of the
>seed drill, which overnight meant you needed to keep one third as much
>of your harvest to plant your next year's crop, therefore trebling your
>yield with one little gadget? I'd say that would be a tough call. ;-)
>
>Na> We have no evidence that archaics
>Na> produced representational art, but plenty of evidence from Australia,
>Na> Africa, Europe and the Americas that at least some paleolithic moderns
>Na> did so. Not every individual member of species Homo sapiens sapiens is
>Na> an artist or musician, but *every* society of modern humans produces
>Na> artistic and musical traditions (though these traditions can vary
>Na> greatly from group to another). The fact that archaics apparently did
>Na> not create art means that their cultures, and at least some aspects of
>Na> their thoughts and motivations differed in basic ways form those of
>Na> peoples living now.
>
>Could well be, although the devil in me has to ask "what is art?" and
>"how long does early art last?" Suppose we have some early weaving, one
>of those things that could well be produced by erectus and not survive,
>and you weave together a couple of different colors. Is that not art?
>Should we reasonably expect, say, a woven bark mat to survive a half a
>million years? Just a thought.
>
>Na> The question remains, though, as to the exact nature of the species
>Na> differences. H. sapiens. sapiens seems highly anomolous in ways that H.
>Na> erectus, and even archaic sapiens, were not. We are the first species
>Na> whose members seem able, without undergoing any sort of biological
>Na> change, to abandon the niche they were born to and set themselves up in
>Na> a whole new way of life. The fact is that, about 10,000 years ago some
>Na> Gatheres and hunters in the Near East abanddoned their tradtional way of
>Na> life, settled into stable agricultural communities and set off this
>Na> whole civilization thing. They perhaps weren't all that great at it, and
>Na> their predicessors haven't proven so either, but we've done better, or
>Na> at least gotten farther down the road, than one might expect of
>Na> creatures whose evolutionary past simply prepared them to be G&Hers. How
>Na> could people just abandon a niche that had figured in their evolution?
>
>One more quibble, one which I think gets lost very often, and which I
>think is important. We (that's the "we" of H.s.s.) *didn't* abandon
>G&H. We don't abandon these things, we add to them. So "we" still
>gather, hunt, trap, farm, and manufacture. And in fact that "we" is
>closer to home than you might realize -- for instance, many spices, some
>of which you probably have in your kitchen, are still gathered from
>forests, not farmed.
>
>Jim Moore (j#d#.moore@canrem.com)
>
> * Q-Blue 2.0 *
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