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Re: The Peters Strikes Back (pterosaurs)
Jim Cunningham (firstname.lastname@example.org) wrote:
<But the shoulder girdle isn't fixed....>
No. What I was trying to say was that the mammal can have a relativelty
shorter arm that utilizes the scapula because the scapula
is not fixed: it works as part of the effective arm in some aspects of its
mechanics, as in walking, running, even when suspended,
thus there is no need to elongate the arm to match the leg in length. In
pterosaurs, the fixed shoulder prevents this. Solution?
Allow the effective arm (arm sans wing finger) to be equal enough to match the
hindlimb in length (reduction of the humerus to
horizontal also shortens the aspect of the arm), and thus shorten the arm.
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)