Cladistics and "Eclecticism"
tdib at OCEANCONSERVANCY.ORG
Mon Feb 4 12:31:06 CST 2002
From: Thomas Lammers
My problem is that I do not believe the assumptions and
methodologies of cladistics (all speciation is dichotomous, ancestral taxa
go extinct at the point of bifurcation, etc.) allow us to ecover
"recognized lineage groups".
I have never in my life encountered a cladist who denied the possibility of
polytomous speciation. Please be assured that, at the very least, most, if
not all, cladists do not make such an assumption, and such an assumption is
not a necessary assumption of cladistics.
As to your second claim, I cannot see how you can aasert that this is a
necessary assumption of cladistics either. I have posted many times, in
great detail on my cladistic understanding of this issue. I wonder why you
seem not to take those points into account. To briefly summarize: Ancestral
taxa do not go extinct unless they go extinct; i.e. unless all the organisms
die. Ancestral taxa become higher taxa when some of their descendants become
historically isolated from others of their descendants, i.e when the lineage
bifurcates. The only thing that comes to an end at the point of bifurcation,
is the simple fact that the ancestral taxon was a terminal branch in the
lineage system, and thus ranked as a species. After bifurcation, it's status
as a species-level taxon is finished. It's life as higher level taxon is
just beginning. How can this be considered "extinction"?
Maybe, when you get right down to it, you don't have any real problems with
claditics - :)
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