22 August 2002 13:00 EST

by Henry Nicholls, BioMedNet News

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Taxonomy is in crisis. The shape of the crisis will be the subject of debates at the Linnean Society in London next month, first on September 5, chaired by Geoff Norton of the University of Queensland, and continued on the 26th by Charles Godfray of the UK's Natural Environment Research Council Centre for Population Biology.

Our grasp on the natural world is slipping, Godfray argued recently in Nature. Since the first attempt by Carl Linnaeus (1707-1778) some 250 years ago to account for and describe every species on earth, we now know there are at least 1.7 million species on earth. (Linnaeus described only about 13,000.) But we also know that the total number of species is likely to be at least 4 million, and could be as many as 100 million. The taxonomic "holy grail" of describing the entire biodiversity of our planet is therefore still some way off, and biologists like Godfray are becoming increasingly concerned that in the absence of "clearly achievable goals" that can attract new sources of funding, taxonomy is losing its way.

The descriptions, phylogenies, cladograms, meticulous drawings and detailed photographs of the species that we have successfully described are fractured amongst a host of museums, and buried in bundles of obscure journals in the inaccessible vaults of a thousand libraries. Even the relatively flush and dust-free discipline of molecular phylogeny - the classification of species according to their evolutionary descent, based on comparison of their biochemical characteristics - is out on a limb and a long way from achieving unity with the wealth of data accumulated by descriptive taxonomists.

This dismal account of today's taxonomy is a far cry from the comparative clarity that Linnaeus was privilege to. As the first person to describe the natural world on a significant scale, he held the vast majority of the taxonomic information available at the time. His impressive overview of the natural world is evident in the Linnaean Collection, acquired by James Edward Smith from Linnaeus' widow in 1784. A temperature- and humidity-controlled room in the basement of the Linnaean Society of London houses the dried specimens of 14,000 plants, 158 fish, 1,564 shells and 3,198 insects. And on shelves up to the ceiling is Linnaeus' library - a collection of about 1,600 volumes, and about 3,000 of his letters and manuscripts. Although by no means the complete record of Linnaeus' endeavors, it nevertheless gives a strong impression of the meticulously labeled, catalogued and cross-referenced world from which the binomial system of nomenclature became established.

In the 10th edition of his Systema Naturae published in 1758, Linnaeus adopted the binomial system - giving each organism a unique name, consisting of its genus and species - with complete consistency and without exception for the first time. Before this, species were frequently described using a poetic string of Latin words. Up against names such as Rosa sylvestris inodora seu canina and Rosa sylvestris alba cum rubore, folio glabro, both of which referred to the same species of rose, it is hardly surprising that Linnaeus' relatively simple system was a hit. Furthermore, it was so exhaustive, authoritative, and persuasive in manner that it molded the paradigm within which his successors would have to work.

However, the success of his system rapidly led to what Godfray calls the "first bioinformatics crisis," as a surge of uncoordinated descriptions and species' accounts led to considerable duplication and confusion. This was ingeniously solved in the late nineteenth century by the emergence of the concept of the "type" specimen - a single specimen of each species that would serve as a reference point for subsequent generations of taxonomists. This evolutionary step (and as Stephen Jay Gould argued in an article in Natural History, a modicum of luck that his system was consistent with, rather than overturned by post-darwinian phylogenetic taxonomy) succeeded in keeping the binomial system buoyant until the present day.

But with the recent explosion of molecular data and dwindling funds, Godfray believes that taxonomy is facing a "second bioinformatics crisis" and must evolve again if it is to survive into the 21st century. "I would like to see different organizations putting forward fully costed proposals to do a unitary taxonomy of whatever group ... to produce fully functioning [web] sites with descriptions, illustrations, molecular, and ecological data where available," he said.

Several projects at London's Natural History Museum are now beginning to match up to Godfray's vision. The largest of these, the Linnaean Plant Name Typification Project, aims to catalogue the type designations and supporting information for some 9,000 plant species named by Linnaeus, and is scheduled for completion in 2007 to coincide with the 300th anniversary of Linnaeus' birth. The head of the project, Charlie Jarvis, said that "a definitive catalogue of Linnaean plant names will provide consistency and stability in the way in which they are applied." He added that "making these data freely available over the web makes them accessible worldwide." It is this sort of stability and accessibility that Godfray is calling for.

Perhaps Linnaeus' tremendous contribution to natural history can serve as a model to unite descriptive and phylogenetic taxonomy and take the classification of our biodiversity out of the archives and onto the web.

Picture caption:
Carl von Linne (Linnaeus), engraving by J. Chapman, National Library of Medicine.

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