Comments to Cladistics/Eclecticism

SKÁLA Zdenek skala at INCOMA.CZ
Mon Feb 11 10:29:02 CST 2002

>point 4. Arbitrariness / subjectivity
>In theory, all groups should get names, but in practice,
>this is usually not done. So the cladists might
>disagree on which groups to name ... The group formation is
>given by the cladogram. Once you have a cladogram, the
>group delimitation is completely unambiguous,
>objective and non-arbitrary. 

Once again: taxa (as you correctly pointed) are the *named* groups. Hence, either you have as many taxa as clades ((2^n)-1; n=number of species) or you need rules to distinguish where to split a cladogram. Here comes the ambiguity - very similar in paraphyletic and holophyletic taxa.

>...eclecticist's group formation is subjective, arbitrary
>and artificial. It is artificial because the "gaps"
>are artificial, and it is subjective and arbitrary
>because the same cladogram will be paritioned into
>different groups by different eclecticists.

Exactly the same problem as in cladistic taxa delimitation - see above. The solutions up to now proposed by cladists are all very similar: "we will name and use the taxa but we do not believe in them" - the "real" system (including all clades as taxa) cannot be practically handled and the useful one (only some clades are named) is only arbitrary. What a science!

>By the way: it's hard or impossible for me not to talk
>about sawflies at all, but I'm perfectly happy with
>calling them sawflies or basal hymenopterans or
>non-apocritan hymenopterans. I can understand that you
>want to talk about reptiles, but can't we leave it at
>reptiles and not Reptilia?

The reason is exactly the same as for developing nomeclature/rules for naming taxa at all:
Are the "sawflies" called by the same name in German? And in Russian? Chinese? Well, names/taxa are indeed communication tools. If you really need to speak about sawflies, you probably know what they are. And if you know it and need it, why not to provide them with an internationally understandable name (=make them a taxon)?

>5. Are monophyletic and paraphyletic groups equally
>The branching events are real
>events and they naturally divide up the live on this
>planet in natural entities, i.e. monophyletic groups.
>...You can make such an artificial classification, but
>it's not scientific because it is based on arbitrary
>decisions, on human "taste", and not on natural

Well, again: your arguments are circular (tautologic). If you define the phylogenetic branching as the only "natural" event, hence only the concepts based on them are natural. I must admit, however, that character change during phylogeny seems quite natural to me as well - and this is the foundation of paraphyly. So: (1) why do you regard character change as unnatural (especially if you use it for the cladogram construction, i.e. to reconstruct those "natural" branching events) and (2) how will you split the cladogram into named taxa if you will not use the character ("phenetic") information?

As concerns the species concept matters: you are obviously misidentifying the phylogenetic species concept ant the biological species concept (Mayrian). You will be probably surprised that it is the phylogenetic species concept that is heavily burdened by the typologic/morphological thinking. Read more on this topic and then try to rethink your current comments on this matter.

Zdenek Skala

More information about the Taxacom mailing list