[Previous by date - Re: Apomorphy-based definitions]
[Next by date - Re: Apomorphy-based definitions]
[Previous by subject - Re: Apomorphy-based definitions]
[Next by subject - Re: Apomorphy-based definitions]
Date: Tue, 28 Aug 2001 14:41:40 -0500
From: "Jonathan R. Wagner" <jonathan.r.wagner@mail.utexas.edu>
To: "Alastair G. B. Simpson" <simpson@hades.biochem.dal.ca>
Cc: PhyloCode mailing list <phylocode@ouvaxa.cats.ohiou.edu>
Subject: Re: Apomorphy-based definitions
This is a multi-part message in MIME format.
--Boundary_(ID_z8fxDDL5GXAJdD3VQKM5ig)
Content-type: text/plain; charset="iso-8859-1"
Content-transfer-encoding: quoted-printable
Alastair G. B. Simpson wrote:
> Well, you move the problem to being one of determining when
> one species transforms into the next one: However one would guess that
> there is no perfect way defining that either.
Actually, I would regard species as being self-bounded, and those
boundaries as (necessarily) "fuzzy." This is entirely analogous to
determining the most recent common ancestral organism of two =
individuals:
the most recent common female ancestor of myself and my sister (at the
organismal level) is our mother, despite the grey area surrounding the =
point
in space and time where she became an individual distinct from her =
mother,
and despite the grey area surrounding the point in space and time where =
we
became distinct from her. Likewise, no one seems to be bothered with the
notion that some cells in my mother's body might share a more recent =
common
(cellular) ancestor with my sister than with me (although this seems
unlikely to me). That is a question which is best addressed at the =
cellular
level, and not the organismal level.
To return to your point, I find that looking at clades in terms of
species (as individuals) clears up the point rather nicely. Would it be
possible for you to clarify how ambiguities in the recognition of =
species at
and around speciation events affect the issue at hand (which, I believe,
involved difficulties in recognizing ancestors)?
Jonathan R. Wagner
9617 Great Hills Trail #1414
Austin, TX 78759
--Boundary_(ID_z8fxDDL5GXAJdD3VQKM5ig)
Content-type: text/html; charset="iso-8859-1"
Content-transfer-encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content=3D"text/html; charset=3Diso-8859-1" =
http-equiv=3DContent-Type>
<META content=3D"MSHTML 5.00.2614.3500" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV>Alastair G. B. Simpson wrote:<BR>> Well, you move the problem to =
being=20
one of determining when<BR>> one species transforms into the next =
one:=20
However one would guess that<BR>> there is no perfect way defining =
that=20
either.<BR><BR> Actually, I would regard species as =
being=20
self-bounded, and those<BR>boundaries as (necessarily) "fuzzy." This is =
entirely=20
analogous to<BR>determining the most recent common ancestral organism of =
two=20
individuals:<BR>the most recent common female ancestor of myself and my =
sister=20
(at the<BR>organismal level) is our mother, despite the grey area =
surrounding=20
the point<BR>in space and time where she became an individual distinct =
from her=20
mother,<BR>and despite the grey area surrounding the point in space and =
time=20
where we<BR>became distinct from her. Likewise, no one seems to be =
bothered with=20
the<BR>notion that some cells in my mother's body might share a more =
recent=20
common<BR>(cellular) ancestor with my sister than with me (although this =
seems<BR>unlikely to me). That is a question which is best addressed at =
the=20
cellular<BR>level, and not the organismal level.<BR> =
To return=20
to your point, I find that looking at clades in terms of<BR>species (as=20
individuals) clears up the point rather nicely. Would it be<BR>possible =
for you=20
to clarify how ambiguities in the recognition of species at<BR>and =
around=20
speciation events affect the issue at hand (which, I =
believe,<BR>involved=20
difficulties in recognizing ancestors)?<BR><BR>Jonathan R. =
Wagner<BR>9617 Great=20
Hills Trail #1414<BR>Austin, TX 78759<BR><BR><BR></DIV></BODY></HTML>
--Boundary_(ID_z8fxDDL5GXAJdD3VQKM5ig)--