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Re: flights of fancy (or "I'm brave, but I'm chicken****")



In a message dated 95-12-05 19:02:48 EST, rowe@lepomis.psych.upenn.edu
(Mickey Rowe) writes:

>Ok, this is (hopefully) my last word in this thread:
>
>> Using hyperbole here doesn't help the situation and makes it sound
>> as if you're raving. "Gibberish"? I hardly think so.
>
>That's ok, George.  I'm not so much trying to convince you so much as
>I'm trying to make sure that your audience appreciates that your
>pronouncements aren't the gospel you appear to me to make them out to
>be.

I didn't know this was a problem for you.

>>> Our moment of inertia around our vertical axis is miniscule compared
>>> to that of a theropod according to contemporary reconstructions.
>>
>> So consider a human runner with a large log horizontally strapped to
>> his or her midsection.
>
>IMHO, that's not even funny.  But in any case, another point I really
>should have hammered home before is that human arms are attached
>directly above the human's center of mass in the antero-posterior
>direction.  Theropod forelimbs are attached well forward of their
>center of gravity, so once again we have reason to expect that arm
>movements in running theropods will not approximate arm movements in
>running humans.
>
>>> Although many of the leg motions will probably be similar for the
>>> two forms ...
>>
>> See? It's not "absolute gibberish" after all.
>
>In the context of our discussion it IS absolute gibberish.  We were
>talking about whether or not feathered arms would hinder a running
>theropod.  You say that humans speak to this point.  If you don't yet
>see that they don't then I fear you never will.  I'll just keep
>working on the next generation...

If you don't see that they _do_ speak to this point...etc., etc.

>>> Maybe it was more efficient for the animal to tuck in its arms
>>> during a high speed chase.  Maybe that's the reason for that
>>> adaptation (exaptation?).
>>
>> No, the reason is more likely to be that _Deinonychus_ had a volant
>> ancestor somewhere in its family tree. Why is this so difficult to
>> accept?
>
>Mainly because the forelimbs of _Deinonychus_ don't look at all like
>modified wings to me.  They certainly don't look like modified bird
>limbs.  However, in the final analysis, I haven't been trying to
>convince you that you're wrong (as you've been doing to the rest of
>the world).  I've only been trying to convince you that your apparent
>certainty is misplaced.

The forelimbs of _Deinonychus_ are DEAD RINGERS for the forelimbs of
_Archaeopteryx_, bone for bone for bone. Where have you been?? How many
papers does John Ostrom have to publish on this before it sinks in?

>> Perhaps I'm wrong, and feathers on the forearms and hands _would_
>> help a running theropod capture more prey, but I don't think
>> anything you've said in this posting or in the previous posting is
>> terribly convincing of this thesis.
>
>We were mainly talking about evading predators, actually.  Have YOU
>ever chased a roadrunner?

If I had to rely on catching roadrunners for a living, I'd be extinct. But
just think--maybe roadrunners would be _even faster_ without their feathers
(but then they wouldn't be ale to fly).