[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Why all the fuss? (flame-free)

Perhaps the following is the third difference which slipped your mind ;-) , but it BY FAR the most important and fundamental difference which causes more difficulties than all the others put together: (3) Whether or not formal paraphyletic groups should be recognized. [Added Note: I just read David's post, and we agree that this is a really big deal].
This is at the very heart of the difference between strictly cladistic (phylogenetic) taxonomy and those who are not strict cladists (many of whom *do* use cladistic analysis). Michael Benton and countless others recognize paraphyletic groups, but use the traditional endings (like Saurischia), so my standardized endings are just a very minor issue that are not at the heart of the debate at all.
It all boils down to whether phylogeny is the *sole* criterion for classification, which would force us to *always* formally embed subclades within larger clades. The price of doing classification in such a strictly cladistic manner is very high and as Benton's paper last year pointed out, it will probably only get worse (although strict cladists clearly disagree and believe it will eventually get better).
Therefore we have two choices: (1) strict cladism (for which we may pay an steep price); or (2) a hybrid system similar to the one used by Benton in his 1997 book. I think most of us would agree that the third alternative, the old traditional eclecticism, is no longer adequate (untestable since paraphyletic groups are not marked as such, and sister group information is lost). If we are going to formally remove Aves from Reptilia, some kind of explicit marker must be left behind to avoid the loss of information and testability.
So that is the heart of the matter. Is the banning of formal paraphyletic groups worth the price (especially in instability and confusion)? And the answer to that depends on how stiff you think that price will be. Benton obviously thinks the price is too high and will only rise as time goes on, while strict cladists believe it will be a shorter term problem and that we will not have to continue paying that price indefinitely. I obviously think a modest amount of explicit paraphyly would avert a lot of these problems, and could give us the best of both worlds, but others clearly disagree.

Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp