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



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.

>> 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...

>> 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.

> 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?

-- 
Mickey Rowe     (rowe@lepomis.psych.upenn.edu)