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Date: Sun, 26 Aug 2001 12:23:31 -0500
From: "Jonathan R. Wagner" <jonathan.r.wagner@mail.utexas.edu>
To: "T. Mike Keesey" <tmk@dinosauricon.com>
Cc: PhyloCode mailing list <phylocode@ouvaxa.cats.ohiou.edu>
Subject: Re: Apomorphy-based definitions
Actually, if species are considered to be individuals (a divisive
suggestion, I know), than an entire species may be considered to be
"ancestral" to another, just as an entire organism is ancestral to another.
If this is held to be the case, the "most recent common ancestor" refers to
a SPECIES, not an organism, and the problem you discuss vanishes. Of course,
as I wrote to the list almost a year ago, there is still a flaw in the
"MRCA" wording of clade definitions, at least for the stem-based definition,
in that it potentially excludes ONE individual (organism or species,
depending on the constituent individual you accept). The "most/least
inclusive clade" clade definitions do ot have this problem.
Wagner
Jonathan R. Wagner
9617 Great Hills Trail #1414
Austin, TX 78759
----- Original Message -----
From: T. Mike Keesey <tmk@dinosauricon.com>
To: Alastair G. B. Simpson <simpson@hades.biochem.dal.ca>
Cc: David Marjanovic <david.marjanovic@gmx.at>; PhyloCode mailing list
<phylocode@ouvaxa.cats.ohiou.edu>
Sent: Friday, August 24, 2001 4:10 PM
Subject: Re: Apomorphy-based definitions
> Perhaps I'm missing something (and this is a difficult thing to
> conceptualize), but can't node and stem definitions really be taken down
> to the level of the individual?