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Re: Two new FAQs: Everything You Wanted To Know About Cladistics



Ken Kinman (kinman@hotmail.com) wrote:

<One thing I would like to see on the second one is some mention of homoplasies 
(convergences and
especially reversals), and how they can sometimes trick both computers and 
people into believing
they are  synapomorphies (and thus can negatively affect reliability).>

  I'd disagree with the inclusion of "reversals" of character polarity and 
expression as a
function or aspect of homoplasy: in a computer analysis, they tend to pull the 
taxon backwards, as
it were, and collapse nodes -- they do not make false synapomorphies.

<And on the first one, I would quibble a little with equating "traditional 
Reptilia" with
"Reptilia minus Aves". Many traditionalists continue to removed both Aves and 
Mammalia from
Reptilia, and leave the traditional paraphyletic synapsids (pelycosaurs and 
therapsids) in
Reptilia. This is the way it was traditionally done for much of the 20th 
Century, and it is still
often done this way outside of cladistic circles.>

  And these fellows are still in academics? *shakes head in wonder* I thought 
Romer and Cox got
rid of all that nonsense decades ago? I'm glad to see people are keeping 
mammals from Reptilia, it
makes me think something's right with the world ... just a pity I forget 
whenever these people
ever included Mammalia in Reptilia since their uses have always opposed each 
other in content, but
anyway....


=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!