RE: Sauropods and lung development

["Stewart, Dwight" <Dwight.Stewart@VLSI.com>]

Also, traits tend to be passed on, even if only obliquely that enhance the
chance of surviving at least long enough to reproduce.  

Dwight

        -----Original Message-----
        From:   Jaime A. Headden [SMTP:qilongia@yahoo.com]
        Sent:   Sunday, September 27, 1998 6:36 PM
        To:     dinosaur@usc.edu
        Cc:     theclaw@sprintmail.com
        Subject:        Re: Sauropods and lung development

        Christopher Srnka wrote:

        <I know this will seem annoying, and will probably earn never-ending
        flaming from the list, but I have to say it.>

          No flaming. At least not from this quarter. So I'll send this to
the
        list. It's something I'm also interested in.

        <How the hell did sauropods develop long necks, (or, for that
matter,
        how did ankylosaurs and stegosaurs develop body armor, or pterosaurs
        their wings, etc.)? I don't mean when, or why, or what the basal
types
        are, I mean how.>

          All I can say here is that these questions are inter-related. To
        answer one, you have to have at least the glimmerings of the answer
to
        either of the others. Answer one, answer two, and the third will
fall
        mostly into place. At least as I see it.

        <I read a lot of smug remarks about creationists (drdino.com was
        deserving of them all, I'll concede; I was almost expecting a link
to
        an X-Files site, with all the paranoid delusions abounding), but one
        of the questions that I have yet to find a satisfactory answer to
is:
        what is the mechanism by which macroevolution is supposed to occur?
        I'm not being facetious here; if someone does have a good answer for
        this, I'd love to hear it.>

          Good ol' evolution is a funny thing. It is influenceable, and
        influencing. And can be both at tyhe same time. Often is, as
        present-time observation as shown, with special respect to the finch
        *Geospiza* in the Galapagos.

          But the driving force in evolution, it would seem, would be the
need
        to adapt. All your friends are doing it, they've got all the toys,
not
        you, so you go find something else. Be a dog, for instance. After
        being left out of the kill, as all your brothers and sisters are
        hogging the carcass like . . . well, hogs . . . you feel put down
and
        start taking a much of grass. Hmm. Not so bad, a bit tough, grainy
        even, but after a while it fills you up. And there's plenty more.
        After all, you could eat fruit, and have, and chewed bark and gotten
        something out of that, right? Now, you evertually breed with a
female
        who happens to have the same appetite, you teach it to your kin, and
        so on. What is readily observable is the evolution of behavior, but
in
        the lopng run, as selectiveness develops a race of grass-eating
dogs,
        the animals begin to physically adapt. While nutrients in grass is
        harder to come by than the same in meat, the gut adapts, and
possibly
        something akin to a cecum develops. The teeth are too derived to
        modify (they are hypocarnivores, already dentally endowed to handle
        the grass in some ways) so just jaw development and muscles in the
        skull would be needed. Perhaps a little something extra, like harder
        enamel, and you have a mostly herbivorous dog. Not much difference:
        it's still a *Canis*, but a new type of one.

          This is all fun and speculation, but illustrates my basic
        understanding of the process of developing a trait that develops
        another, that develops another, and so on. Hence two factors above
(an
        unexplored niche, and isolation) are the primary factors in _any_
        process of evolution.

          Now, before I bury myself in another corner I can't dig myself out
        of (or have I already done this with my limitied grasp of
evolution?)

        ==
        Jaime A. Headden

        Qilong, the website, at:
        http://members.tripod.com/~Qilong/qilong.html
        ---
        All comments and criticisms are welcome!

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