Re: Dinosaurian Class

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

I wrote:

<It's: Amniota including Diapsida (crocs, dinos, birds, lizards) and
Synapsida (pelycosaurs, us) with the outgroup as Anapsida (your
favorite box turtle, for instance).

+--+--Anapsida
   +--+--AMNIOTA
      +--+--Diapsida
         +--Synapsida>

Bill Adlam wrote:
 
<<This classification has now fallen out of favour. It is more likely
that Chelonians are Diapsids which secondarily reverted to the anapsid
state (their skulls are clearly heavily modified). Other anapsids are
a paraphyletic mix of early Amniotes.
 
I do not know the difference between Reptilia (new definition) and
Diapsida. 

<<<Does this mean we're all bacteria?<g>>>>

<Bacteria exist on a different branch of the tree of life than do any
other form of life, extant or extinct.>

  This was where I stuck my foot in my mouth. Read on:

<Pretty much, we are derived from the most recent common ancestor of
bacteria and all other life, with bacteria as the outgroup. This is to
say, we are derived from a bacteria-like creature that is not,
essentially, bacteria. Same for dinos, birds, etc.>
 
<<Cladistic assumptions break down when dealing with bacteria,
especially eubacteria, because of horizontal gene transfers. The same
goes for viruses, if they are to be included at all. Bacteria should
be separated for this reason, and not because they form a clade.>>

  My knowledge of bacteria and their place on the great tree of life
is quite limited and only in textbook cladograms and basic,
grade-school knowledge (not being a bacteriologist or microbiologist,
or having any greater knowledge being a passing grade in knowing what
was written). So I got by being stupid on the matter and must now gain
back my honor and read up.
  Thanks to Bill and Jonanthan for their help in setting me strait!

  Jaime A. Headden
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