Re: Adaptive Niche of Arc

J. Moore (
Sun, 18 Jun 95 18:11:00 -0500

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 (

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