The subjective nature of Linnaean categories and its impact in evolutionary biology and biodiversity studies (original) (raw)
Related papers
2005
Linnaeus and other 18"" Century naturaii.sts practiced nomenclature in a way that associated laxon names more strongly with taxa (group.s) than with the categorical ranks of the taxonomic ("Linnaean") hierarchy. For IS'"* century naturalists, ranks functioned merely as devices for indicating hierarchical position that did not alTccl I he application of taxon names. Consequently, taxa did not change their names simply because of changes in rank. For example, the name RepiiUa did not change when the rank of the taxon designated by that name was changed from order to division or class. During the 19''' Century, a different approach to nomenclature emerged that made rank assignment centra! to the application of taxon names. Under this rankbased approach, which forms the ba.sis of the current botanical and zoological ctxlcs, names are implicitly defined in tenns of ranks and types and are therefore more strongly associated with ranks than with the taxa to which they refer. Consequently, taxa change their names simply because of changes in rank. Forexample, if the rank of die taxon/Icícacrae is changed from family to .subfamily, its name must change to Aceroklnae. Phylogenetic nomenclature is a new approach that ties taxon names to explicitly evolutionary concepts of taxa through definitions that describe taxa in terms of ancesu-y and descent. This approach once again associates ia.\on names more strongly with taxa than with ranks and thus represents a return, updated with evolutionary principles, to an approach similar to that practiced by Linnaeus and other 18'''Century naturalists,
Taxon, 2004
The participants in the Workshop were brought together to consider how best to integrate the needs of phylogenetic classification given our current system of naming the world's biota. The Workshop was developed as a follow-up to the 2001 Smithsonian Botanical Symposium held in Washington, D.C., the results of which were published in Taxon [volume 51(1), 2002]. The Smithsonian symposium was attended by 190 scientists from numerous countries. At that meeting issues concerning the Linnaean naming system and the needs of an emerging phylogeny-based classification were discussed. Participants in this follow-up Workshop at the Hunt Institute in Pittsburgh were selected on the basis of their response to a widely distributed announcement about the planned workshop. In addition, several individuals were specifically invited because of the particular perspective they would bring to the discussion. It is recognized that the results of the workshop have predominantly American and botanical perspectives. Although the discussion centred on the International Code of Botanical Nomenclature (ICBN) (Greuter & al., 2000), many of the comments are also applicable to the Zoological and Bacteriological Codes as well. This report is offered for discussion and critique with the hope that it will be useful to the community of taxonomists and biologists at large in understanding and formulating a workable system of nomenclature and classification.
Conceptual issues in phylogeny, taxonomy, and nomenclature
Bijdragen tot de Dierkunde
Phylogenetic hypotheses are designed and tested (usually in implicit form) on the basis of a set of presumptions, that is, of statements describing a certain order of things in nature. These statements are to be accepted as such, no matter whatever evidence for them exists, but only in the absence of reasonably sound evidence pleading against them. A set of the most current phylogenetic presumptions is discussed, and a factual example of a practical realization of the approach is presented.
1997
During the post-Darwinian history of taxonomy, the Linnaeän hierarchy has maintained its role as a means for representing hierarchical taxononaic relationships. During the same period, the principle of descent has tallen on an increasingly important role as the basis for reformulated versions of fundamental taxonomic concepts and principles. Early in this history, the principle of descent provided an explanation for thé existence of taxa and implied a nested, hierarchical structure for taxonomic relationships. Although an evolutionary explanation for taxa contradicted the Aristotelian context within which thé Linnaean hierarchy was developed, the nested, hierarchical structuré of taxonomic relationships implied by evolution was compatible with the practical use of the Linnaean hierarchy for conveying hierarchical relationships and seems to have reinforced this practice. Later changes associated with the development of taxon concepts based on the principle of descent led to changes in the interpretation of the Linnaean categories as well as certain modifications related to use of the Linnaean hierarchy in representing phylogenetic relationships. Although some authors questioned use of the Linnaean hierarchy in phylogenetic taxonomies, most continued to use it in one form or aiiothen Moré recently, taxonomists have considered the relevance of the principle of descent to nomenclature. They have found fundamental inconsisteneies between concepts of taxa based on that principle and methods \_ currently used to define taxon names, which are based on the Linnaean hierarchy. Although these inconsistencies can be corrected without totally eliminating the Linnaean hierarchy, the necessary changes would greatly reduce the importance ofthat hierarchy, particulariy in the area of nomenclature. Moreover, the eariier development of taxon concepts based on the principle of descent effectively proposed taxonomic categories of greater theoretical significance than those of the Linnaean hierarchy. The historical trend of granting increasing importance to the principle of descent has reduced the significance of the Linnaean hierarchy to the point where it may no longer be worth retaining.
Comptes Rendus Biologies, 2006
The recent multiplication of cladistic hypotheses for many zoological groups poses a challenge to zoological nomenclature following the International Code of Zoological Nomenclature: in order to account for these hypotheses, we will need many more ranks than currently allowed in this system, especially in lower taxonomy (around the ranks genus and species). The current Code allows the use of as many ranks as necessary in the family-series of nomina (except above superfamily), but forbids the use of more than a few ranks in the genus and species-series. It is here argued that this limitation has no theoretical background, does not respect the freedom of taxonomic thoughts or actions, and is harmful to zoological taxonomy in two respects at least: (1) it does not allow to express in detail hypothesized cladistic relationships among taxa at lower taxonomic levels (genus and species); (2) it does not allow to point taxonomically to low-level differentiation between populations of the same species, although this would be useful in some cases for conservation biology purposes. It is here proposed to modify the rules of the Code in order to allow use by taxonomists of an indeterminate number of ranks in all nominal-series. Such an 'expanded nomenclatural system' would be highly flexible and likely to be easily adapted to any new finding or hypothesis regarding cladistic relationships between taxa, at genus and species level and below. This system could be useful for phylogeographic analysis and in conservation biology. In zoological nomenclature, whereas robustness of nomina is necessary, the same does not hold for nomenclatural ranks, as the latter are arbitrary and carry no special biological, evolutionary or other information, except concerning the mutual relationships between taxa in the taxonomic hierarchy. Compared to the Phylocode project, the new system is equally unambiguous within the frame of a given taxonomic frame, but it provides more explicit and informative nomina for non-specialist users, and is more economic in terms of number of nomina needed to account for a given hierarchy. These ideas are exemplified by a comparative study of three possible nomenclatures for the taxonomy recently proposed by Hillis and Wilcox for American frogs traditionally referred to the genus Rana. To cite this article: A. Dubois, C. R. Biologies 329 (2006).