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RE: "running" elephants - locomotary analoges



Greg Paul (GSP1954@aol.com) wrote:

<For example let's say that someone published a paper that tried to
estimate the flight performance of extinct giants via computer simulations
of required muscle mass, bone strength or whatever. Let's say the paper
correctly calculated the flight parameters of a pigeon, and then went on
to conclude that Quetzalcoatlus would have been incapable of any flight
because it was too big and its thin walled bones too weak (prior to the
discovery of super pterosaurs there were calculations "showing" that
fliers could not be larger than pterandonts). Such a study would clearly
be incorrect because the anatomical form of Quetz was obviously adapted
for flight. This would be true even if the methodology latter correctly
calculated the performance parameters of larger living fliers, since the
anatomical flight adaptations of the extinct giant cannot be refuted. It
would be necessary to conclude that the methodology used to estimate the
performance of super pterosaurs were errant - not surprising since
vertebrate locomotion is extremely complex and remains poorly understood
in many regards, so attempts to reconstruct extinct forms via detailed
computer simulations are prone to serious mistake (much as until recently
the flight of bees was not explainable with know aerodynamics).>

  While ignoring the known and performed flight simulations of Q flight, I
will say that this comp data would be of high interest since it would
offer concrete, testable data that would have a result and conclusion that
are strong and sound. Find a flaw in the data and you know exactly what it
leads to. Not so on a basic human assumption outside of the box. But could
this scenario not lead one easily to indicate that these "flight worthy"
characters are evidence of regressiong of flight ability inversely
proportional to increasing size? One could easily offer this in many
birds, for instance many galliforms seem to follow this trend. Or among
the heavier parrots, the kakapo comes to mind. Why would having a
"obviously flight worthy" wing mean it could actually fly or do so well?

  The application of Jim Cunningham's data may only show an evolutionary
novelty from an originally well-functioning flight wing in smaller,
less-advanced azhdarchids. This does not mean the data is wrong. Just
different from a method of incomparable position. A blind man and a deaf
man perceive the world differently; by eye or ear, different methods reach
different conclusions, but nothing says either is wrong. John has been
very careful in presenting the exact data used to reach his conclusions,
it is this data that should be investigated, not anecdotes.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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