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Re: Classification: A Definition



----- Original Message ----- From: "Botterweg, Rrp" <ronald.botterweg@capgemini.com>
Sent: Monday, May 14, 2007 10:47 AM


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.

I still don't understand what you mean. The names will stay, only the ranks will stop being mandatory. You will be allowed to actually use Euhadrosauria, even though it has no rank and even though it is part of a traditional family (Hadrosauridae) but includes two traditional subfamilies (Hadrosaurinae and Lambeosaurinae). Instead of "subfamily Hadrosaurinae", you will be allowed to just say "Hadrosaurinae". That's what I mean.


Since phylogenetics/cladistics show relative distances between taxa/clades,

The term "distance" is used for branch lengths

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.

You know how to find a file on a computer: files are grouped in folders, and folders again in folders. (That's even often called a "tree".) There are no restrictions on how long such a chain of nested folders can be, the folders don't have ranks (nobody would say that C:\WINDOWS\system32 is or is not somehow at the same rank as C:\Program files\IrfanView), and there are no rules that some folders may not directly contain files but only folders. This is what applied phylogenetic nomenclature looks like, and I have mentioned a few important differences to traditional classification.


Or have a look at how languages are recognized as belonging to clades the names of which lack ranks. There have been a couple of attempts to introduce ranks there, but they have all been so unsuccessful that Wikipedia doesn't even mention them. Compare, for example, the infoboxes of http://en.wikipedia.org/wiki/Sotho_language and http://en.wikipedia.org/wiki/Bambara_language on the one hand to that of http://en.wikipedia.org/wiki/Mountain_zebra on the other. Which method do you consider more useful? Which contains more information?