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Re: Why all the fuss?



> So to recap: what we have are two rival taxonomic systems both of
> which in practice build trees which reflect our best guess at
> phylogeny.  What are the _actual_ differences between the systems?
>
> Roughly none.  Well, OK, there are three that leap to mind but none of
> them count. [...]
>
> Difference #1. The Linnaean system uses binomians and cladistic system
> doesn't.  Except that in practice, the cladistic system still does, so
> that's not something that needs to worry us.

As "soon" (hwa, hwa) as the PhyloCoders will have chosen one of the IIRC 13
proposed methods to get rid of the genus, which is after all a rank, it
might become a real difference.

> Difference #2. The Linnaean system dignifies some nodes with labels
> which we call "ranks".

No, it takes assorted taxa and puts them onto a varying number of levels.
And the loosely content-based taxa are "defined" by a diagnosis that can
change, they are not necessarily nodes, stems or whatever.
        I hear your next argument coming: cladists frequently argue just
like others about whether certain basal forms should be included or not in
whatever holophyletic taxon because there is much quarrelling about the
published definitions, as well as e. g. philosophical arguments about
whether crown groups are a good idea. True. Should end when PhyloCode is
implemented, we'll see.

> People who think that ranks have some utility
> will continue to use them (and of course they're implicit in some
> taxon names' endings) but people who don't like them ignore them today
> and will keep doing so.

The PhyloCode will allow everyone to use or ignore any ranks, they just
aren't part of the system, unlike the existing codes. (I hate to argue from
a draft that is, at the moment, just sort of another freak website...)

> Again, this is not something we need to fight about.

This sounds very obvious. It isn't. "Oh boy, was the Cambrian explosion
special! Whole phyla sprang into existence! Not one phylum originated
afterwards, only a few classes and smaller stuff! Did evolution work the
same way as now?" I've read this circular argument several times. It is
circular because taxa that diverged a long time ago are more likely to be
called phyla than younger ones, simply because the possibility that
"intermediate" forms die out increases with time and diversity can increase
with time, too. "At the class level the K-T mass extinction was a non-event
for vertebrates, unlike some others when Placodermi, Acanthodii and
Conodonta vanished. So it wasn't that bad overall.", or more specific,
"Lizards were unaffected by the K-T in western NA, of all Squamata only
Mosasauridae, but no other family, died out" -- but 30 % of species. And so
on. Ranks can be very misleading.

> Actually, the third difference I had in mind has slipped away from my
> hindbrain as I've been writing the last two paragraphs.  So it can't
> have been that big a deal!

Was it the use of paraphyletic taxa? This is a big deal IMHO...

> Now watch as the replies escalate into a brutal and bloody flame-war
> :-)

Don't worry, I'm too tired :-)