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Date: Fri, 09 Feb 2001 14:24:06 -0500
From: Philip Cantino <cantino@ohiou.edu>
To: PhyloCode@ouvaxa.cats.ohiou.edu
Subject: Fwd:
I would like to add to the several messages that have already been posted in answer John Janovec's questions. John wrote: > >I hate to be a pessimist, but I observe very little to no discussion of the >groups for which no to few phylogenies are available. How will the Pcode be >applied to the many groups of organisms which are not represented by >phylogenies? Insects come to mind. Many tropical plants at the subfamilial >level come to mind. I hear plenty of arguments for application of the Pcode >with regard to vertebrates and perhaps even higher levels in the plant >world, but how in the hell can we expect to apply a Pcode classification and >nomenclature to understudied and very diverse groups? The PhyloCode is designed to govern the naming of clades (and, eventually, species). In a poorly studied group, the PhyloCode will still facilitate naming clades to the extent that they have been discovered. In some groups, only a few clades have been found, and these can be named using the PhyloCode. If one wants to name other phenetically-defined assemblages of species, then the current codes are available to do so. The PhyloCode may or may not ever replace the rank-based system, but it certainly won't replace it in the near future. Some magazine articles have emphasized the abandonment of "Linnaean" nomenclature (after all, journalists love controversy), but it is clear to me that the two systems will operate in parallel for long while. Thus, the rank-based system will remain available for those who want to delimit and name phenetic groupings, and the PhyloCode will be available for those who wish to discover and name clades. People whose study groups are poorly known phylogenetically may want to use both systems in the taxonomy of a single group. If so, symbols can be used used to indicate which names are governed by which code. > >If we freeze names of clades based on current phylogenetic understanding (or >misunderstanding), then what happens when the phylogenies change? The names >remain the same but get placed in different clades. What will this do to >the (utilitarian) system of communication? Confusion? Chaos? Disorder? >And what do we tell the general consumers of taxonomic information-- the >agrarians, the foresters, the high school teachers, or even local indigenes >in the Neotropics being trained to recognize local plants as assistants in >biodiversity surveys. As Jonathan Wagner pointed out, changes in our understanding of phylogeny will change the content of clades named under both systems. Moreover, the rank-based system is plagued by an additional source of instability that is not found in phylogenetic nomenclature: clade names may change due solely to shifts in rank, without any change in our knowledge of phylogeny. This has been pointed out repeatedly in many different papers, so I won't belabor it here. > >Is the Pcode really a communication and recognition >device? It is a device for communication (of information about phylogeny) but not for recognition (i.e., identification). This is equally true of the current system of nomenclature, in which taxon names are operationally defined in terms of ranks and types. For example, in the traditional system, Asteraceae is the taxon of family rank that contains the type of Aster. From this information alone, you could not recognize a member of Asteraceae. Identification requires descriptions and keys, and these should be provided no matter which system of nomenclature is used. >Is the Pcode truly rank-free? >Won't there always be a ranked hierarchy in nature, regardless of the >classification system applied? Of course nature has a hierarchy because the evolutionary process creates a hierarchy of relationships. Clades contain clades contain clades, regardless what system you use to name them. However, phylogenetic nomenclature is rank-free in the sense that ranked categories (e.g., genus, family) are not mandatory. You can still use them if you want to, but they have no bearing on the spelling or application of names. > >Don't we have a great deal of basic biodiversity survey work to do before we >can just drop the current system and convert to a new system? As explained above, I don't think anyone is suggesting that we "just drop the current system and convert to a new system." We are introducing a new system that we feel works better for naming clades and species. It will function in parallel with the traditional system for a while (probably a long while). If it works well, the community of biologists MAY (or may not) eventually decide that the old rank-based system is no longer needed. Whether or not this ever occurs, the PhyloCode will be extremely useful in the short term by making it far easier to name clades than it is currently. At a time when clades are being discovered at an unprecedented rate, this in itself is an important contribution. Phil Philip D. Cantino Professor and Chair Department of Environmental and Plant Biology Ohio University Athens, OH 45701-2979 U.S.A. Phone: (740) 593-1128; 593-1126 Fax: (740) 593-1130 e-mail: cantino@ohio.edu