Farewell to: Farewell to Species - reticulation

A Mitchell am16 at GPU.SRV.UALBERTA.CA
Thu Feb 3 12:38:47 CST 2000

Hubert Turner wrote:

>On Tue, 01 Feb 2000 19:31:38 -0800, Curtis Clark wrote:
>>At 11:24 PM 00.02.01 +0100, Hubert Turner wrote:
>>>Because permanent splits are the only things recognized by a
>>>cladistic analysis,  in the ideal case (i.e. when no homoplasies
>>>occur to muddle the outcome of the analysis) the cladogram would
>>>A   B  C  Z     D
>>> \   \/   |    /
>>>  \   \   |   /
>>>   \   \  |  /
>>>    \   \ | /
>>>     \   \|/
>>>      \   /
>>>       \ /
>>>        /
>>>       /
>>>because apomorphies cannot be shared by common descent by only Z
>>>and D, or by only (B, C) and Z, or by only (B, C) and D. The whole
>You wrote:
>>In real life, this doesn't often happen. Hybrid species or lineages
>>get (or keep) more apomorphies from one parent than the other, so that
>>resolutely cluster with one parent's clade.
>Obviously, and I did not add the provise 'in the ideal case' for exactly
>this reason. In practice, Z will indeed have more apomorphies in common
>with either D or (B, C), and group accordingly, but with the other
>apomorphies showing up as either parallel developments or as reversals in
>the sister group of Z.

Well how many of us deal with "the ideal case" in our (real life) every
day work?  If any of us did, we would soon be out of a job because nobody
needs a Ph.D. and years of experience to do something as easy "the ideal
case" (every character has a consistency index of 1 and phylogeny
reconstruction is child's play).  So in the "practical, ordinary,
conventional, usual, everyday case" cladistics will fail to accurately
represent hybridization events.


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