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Re: the tonight show



In a message dated Wed, 10 Jan 2001 10:48:18 PM Eastern Standard Time, "Ken 
Kinman" <kinman@hotmail.com> writes:

<<Nick,
      I hope you are right, that what you said below is what George really 
meant...If C is a modern Galliform, and E is a modern Blue Jay, there are 
almost certainly 
more intermediate forms on the line between B (Hesperornithiform or 
Ichthyornithiform) and the blue jay than between B and the galliform>>

I disagree that this is true in any important sense.  If the generation times 
in the two lineages average out to be the same, then there are exactly as 
many intermediate forms leading to the galliform as there are to the 
passeriform.  It may be true that there is more morphological disparity among 
the intermediate forms leading to the passeriform, but that is a different 
claim.


<<Just like 
the cyanobacteria of today are far more closely related to any of the 
cyanobacteria living billions of years of ago than they are related to other 
modern bacteria.>>

Huh?  Phylogenetically, this is like saying that a modern jay is far more 
closely related to any of the theropods living 67 million years ago than it 
is to a horse.  True, but not germane to the discussion at hand.


<<In elegant 19th Century prose, he [Darwin] says that sister 
groups that have evolved at greatly different rates should be at different 
taxonomic ranks in classifications.  In so many words he was advocating the 
use of paraphyletic groups when necessary.>>

If this is what he said, then what he said does not logically entail 
paraphyly.  Say the genus *Opisthocomus* (hoatzins) is the sister group to 
the family Musophagidae (containing various genera and species of turacos).  
*Opisthocomus* and Musophagidae are sister groups of different ranks (genus 
and family, respectively), but neither need be paraphyletic.

--Nick