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RE: Classification: A Definition



Probably most people only got the "message truncated" error, so I repeat the 
whole post:

-------- Original-Nachricht --------
Datum: Mon, 14 May 2007 10:47:00 +0200
Von: "Botterweg, Rrp" <ronald.botterweg@capgemini.com>
Betreff: RE: Classification: A Definition

> David Marjanovic wrote:
> 
> "It's not really an alternative. Phylogenetics and PN together make
> classification completely superfluous; it just drops out of the
> equation; neither it nor any alternative is needed. "How should I
> translate a tree into a classification" turns out to be a wrong
> question, like Lowell & Dingus's famous "why did Napoleon cross the
> Mississippi"."
>
> Unless I misunderstand something here (and would love to be informed),
> I tend to say that this goes a bit too far, at least as far as the
> lower taxonomic levels are concerned (family and particularly below),
> for a very practical reason: overview.
>
> Since phylogenetics/cladistics show relative distances between
> taxa/clades, it might become rather impractical when dealing with large
> numbers of taxa (genera, species), one tends to loose overview (such as
> the large numbers of Amphibian species I am contributing to at
> AmphibiaWeb and 'Amphibian Species of the World', on-line version, at
> the AMNH), but I admit I am approaching this from a database angle.
>
> So, although phylogenetics/cladistics definitely constitute a more
> 'natural' system and 'traditional' classification an much more
> 'artificial' one, I think the latter still has its merit from the
> practical point of maintaining an overview of large numbers of taxa,
> hard to achieve with phylogenetic/cladistic trees.
>
> Unless you maintain that PN can do the same, but in that case I would
> say that it does offer an alternative classification and 'translation
> from tree into classification'.
>
> Please clarify and thanks in advance.

I don't quite understand what you mean. Maybe you make the misunderstanding 
Benton made in 2000, that the end of classification would also be the end of 
nomenclature. It isn't, and that's where the term "phylogenetic nomenclature" 
comes from. There will not be fewer names for clades, there will be more.

You mentioned AmphibiaWeb. Even without phylogenetic nomenclature, Frost et al. 
coined lots and lots of rankless clade names in their huge work, because they 
want to talk about their tree and suffer from the fact that there are never 
enough ranks to give every interesting taxon a rank. Unfortunately, almost none 
of these names have a phylogenetic definition; this means that, when fossils 
are inserted into the topology they found, there is in most cases no way to 
find out whether they belong to the same taxon as their closest extant 
relatives or not; furthermore, most of the names by Frost et al. are completely 
inapplicable to any topology except theirs -- for the same reason.*

Compared to Linnaean classifications, all that phylogenetic nomenclature will 
take away is the illusion that some taxa are somehow at some kind of same level 
and therefore somehow comparable (for example, that it's possible to count 
families). That is not a bug, it's a feature. :-)

* For a long rant about the nomenclatural practices of Frost et al., or rather 
the lack thereof, see Appendix 6 (which will be online at 
http://www.systematicbiology.org/) of:
David Marjanovic & Michel Laurin, next month. Fossils, Molecules, Divergence 
Times, and the Origin of Lissampibians. Systematic Biology 56(3): 20 pp.

Incidentally...

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...I can't cite a source, but I've read that this kind of disclaimer is not 
required under any law in the world, and that the popular belief to the 
contrary is false.

While I am at it...

>  _/|_    ______________________________________________________________
> /o ) \/  Mike Taylor <mike@indexdata.com> http://www.miketaylor.org.uk
> )_v__/\  "Why did the avian thoracic and lumbar spinal column fuse into
>          a solid clump? / To get to the other side" -- zenlizard

I know the ornithologists still do it, but it makes zero sense to talk about 
"thoracic" and "lumbar" vertebrae in birds, let alone to say that "the lumbar 
vertebrae" fused to the sacrum (as it was explained to me in a lecture on avian 
osteology, honest). Birds and their ancestors have never had a difference 
between thoracic vertebrae (with normal long ribs) and lumbar ones (with short 
or no ribs).
-- 
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