Re: Philosophies for Character Ordering

["Jaime A. Headden" <qilongia@yahoo.com>]

David Marjanovic (david.marjanovic@gmx.at) wrote:

<Yes. Though, in this case, the simultaneous incorporation of 2 verts into
the sacrum can only happen when one is a dorsal and the other a caudal;
otherwise the one closer to the sacrum can't help being sacralized first.>

  No. There are at least three ways I can think of this immediately: 1,
two caudals incorporate into a unit, then are incorporated at once into
the sacrum (two events, but one step from 6 to 8 sacrals potentially); 2,
two dorsals instead of two caudals; and 3, as noted, one dorsal and one
caudal simultaneously. These can happen through secondary effects of
increased tendon formation throughout the sacral region, accession of
associated vertebrae as a functional unit, and fusion through the series
can occur both cranially and caudally at the same time, as occurs during
ossification of the vertebral endochondria. Old age forces some vertebrae
to become locked and assumptively that pressure forces the fusion to occur
to relieve stress. 

<So we still have 2 steps, even though they happen at the same time.
Right?>

  The series cannot be considered to occur over two steps: it would have
to be a single step, separate from "incorporated dorsal" and "incorporated
caudal," where treating it as having both would be a polymorphism. If they
happen at the same time, sequentially, they occur in one event, and are
one single evolutionary novelty, not two.


  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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