[Taxacom] Usefulness (was: Defining polyphyly)

Barry Roth barry_roth at yahoo.com
Wed Dec 15 19:07:15 CST 2010

Because of organic evolution (remember him?), it's a plausible prediction that a newly discovered character-state in one member of a holophyletic group will also be found in other members of that group.  The same is true for a paraphyletic group, but the character-state may _also_ be expected in the excluded taxa that make the group paraphyletic.  So holophyly is a more efficient way of circumscribing groups when you're interested in that type of search.
Barry Roth

--- On Wed, 12/15/10, John Grehan <jgrehan at sciencebuff.org> wrote:

If course from my perspective Curtis did not. A group that is defined by
the exclusion of some members of its clade does not seem 'natural' in
any way that reflects that nature of hypothesized entities. It would be
like saying humans are all those with unique features x, y, and z, but
excluding anyone from New Zealand (although to some that might be
perfectly natural!).

John Grehan


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