[Taxacom] Phylogenetic Classification? (the Dawn of Birds)

Kenneth Kinman kennethkinman at webtv.net
Tue Jul 28 17:07:16 CDT 2009

Hi Curtis,
      It's too simplistic to view it as a reptile's egg hatching into a
bird.  It's more like one "species lineage" giving rise to a group
evolving at a normal rate (therizinosaurs), while it's sister species
lineage began a series of saltational evolutionary events resulting in
Class Aves.   
       The first saltation may have taken only a few million years, but
still rapid on a geological scale, and a bunch of major changes occurred
(including evolution of vaned feathers, changes in eggshell
microstructure, and morphological changes in the shoulder, wrist, etc.).
This would set the stage for future developments which happened more
gradually (such as powered flight).
      Therefore, if you are an evolutionary taxonomist and want to draw
the most appropriate line between a Class Reptilia and a Class Aves, I
believe this is the best place to do it.  Archaeopteryx is not
appropriate, because there are no major saltations in the part of the
avian evolutionary tree containing Archaeopteryx and it relatives
(trodonts, dromaeosaurs, etc.).
       For those who balk at including something like a velociraptor in
Class Aves, just remember that they were far more bird-like than they
were portrayed in Jurassic Park (and were actually about half that
size).  Velociraptor ancestors were smaller, had vaned feathers, and
could glide or even fly (probably just as well as Archaeopteryx).
Velociraptors are thus essentially secondarily flightless, ground birds
(like ratites), sort of like a heavy-set, meat-eating ostrich, but with
teeth, a long tail, and wicked claws.  However, Archaeopteryx also had
teeth, a long tail, and claws on their wings, and we have no trouble
regarding it as a bird. 
                   Ken Kinman
Curtis Clark wrote: 
And that is worse than having it riddled with undefined macroevolution
(either the pattern or the process), how? 
Leaving aside your mosses (which I don't know enough about to
challenge), I see nothing in the evolution of birds from dinosaurs,
based mainly upon Ken's analyses (so not biased by
cladophylocreationistic thinking) that would suggest any unusual
macroevolutionary events beyond the usual speciation as seen though the
window of fossilization. It's all well and good to say that the Reptilia
gave rise to the Aves, but at some point a reptilian egg had to hatch
into a bird, and that either has to represent a documented (if, of
course, testably hypothetical) macroevolutionary event, or else it's

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