paraphyly

[Thomas DiBenedetto]

-----Original Message-----
From:Larissa Vasilyeva
... suppose, one finds such characters that divide a genus into quite
natural subgenera. Then, subgenera are paraphyletic extensionally since they
do not include all of the original ancestor's descendants, but they are
monophyletic intensionally
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No, I disagree with this. If you divide a higher taxon into natural
subgroups, the subgroups are NOT paraphyletic. For example, Mammalia is a
monophyletic higher taxon (let's make the analogy to your "genus"). Primates
is a monophyletic sub-taxon (analagous to your "natural sub-genus"). Is
Primates paraphyletic because it does not include the ancestral mammal? No,
of course not. Critters that are Primates are also Mammals. Primates is
monophylteic because it includes the ancestral Primate - it neednt containt
the ancestral Mammal, or Animal or Eukaryote.
*************
Thus subgenera are monophyletic and paraphyletic simultaneously,
************
Sorry, not possible -

Tom diBenedetto