Phylocode, Cladistics and Eclecticism ...

[Thomas DiBenedetto]

-----Original Message-----
From: Ken Kinman
     To use your mother-daughter + daughter way of looking at it, the
mother-daughter is still one species, while the other daughter has one or
more apomorphies (changes are necessary for its speciation to occur).
********
The point Ken, is that the "mother-daughter" is still one species only
because you say so. I dont say so. You are expressing an opinion, based on
your concept of what a species is - you are not expressing some objective
truth about the natural world. Your conception of species is that an
apomorphy needs to be evolved before something becomes a species. My view is
that an apomorphy is usually necessary for us to have the evidence to
recognize that something has happened - but that "something"- the divergence
of the lineage -  is what should underlie the classification. As a cladist,
I support the notion that classification should be based on the
relationships between lineage branches . These relationships are defined by
the process of descent. The two daughters that are the result of a lineage
divergence are sisters - they both have the same relatonship to thier
mother-species, and they are eachothers closest relative.
****
...the apomorphic population starts out small and
should be regarded as a budding off of the original mother population.
*******
Why should it be so considered? Becuase it is small? How small does it have
to be? Suppose the "apomorphic" population represents half of the original
population?
**********
This is a natural evolutionary event which automatically truncates the
mother leaving her a paraphyletic entity,
**********
 Yes it is a natural event, but the mother is only truncated if you
INTERPRET that natural event in such a way as to remove the "bud" from the
mother's taxon. When a taxon gives off a "bud", there is no natural reason
to claim that the "bud" is no longer part of the taxon. That is a human
naming decision. And I think it is nonsensical. The "bud" should remain a
part of the original taxon, as does the other, non-apomorphic branch. That
is why the original taxon is now a higher taxon. Being part of a taxon is a
funciton of a groups descent relationships. Once part of a taxon, all
descendants will always be part of that taxon. That is an interpretation of
"taxon" that aligns it with our notion of "lineage". Having been born into
the
Eukaryote-Animalia-Vertebrata-Osteichthys-Tetrapoda-Mammalia-Primates-Homo-s
apiens lineage, nothing that ever happens ot our descendants can nullify
this inheritance. They will always be part of that lineage system, and so
they will always be part of those taxa. Just as birds will always be part of
Reptilia-Archosauria-Dinosauria, and just as the "buds" will always be part
of their mother's lineage - and hence their mother's taxon. As a new
species, they are part of a new taxon _in addition_ to being part of all of
the taxa in their history. To the extent that you truncate the mother's
taxon, you are disengaging your taxic system from the lineage system, and
rendering your taxic system as unable to be reflective of the history of
lineages.

Tom DiBenedetto