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Re: giant birds



Chris Brochu wrote:
 
> It (BCF) can be forced into compatibility with standard phylogenies - 
> in fact, any scenario can be.  I could envision scenarios in which 
> every single character in the matrix is independently derived on 
> every single branch on the tree.  The question is, is that the 
> simplest scenario supported by a given tree?

I'm not quite sure I follow you Chris, but I suspect like me you think 
we need some objective criterion (i.e. parsimony) to test between 
hypotheses. Tree construction under parsimony is based on minimising 
character reversals. If homoplasy (independent character derivation in 
Chris's words) was this rampant in evolution, we'd never get congruence 
between trees (of extant organisms) based on morphological and 
(independent) molecular characters. We either treat the tree as a 
hypothesis of character evolution or we don't. So on that basis, BCF is 
very unlikely to be supported by a given tree.

Kendall

----------------------
Kendall Clements
k.clements@auckland.ac.nz