[Paleopsych] New Scientist: Time for Linnaeus to leave the stage

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Time for Linnaeus to leave the stage
New Scientist vol 183 issue 2464 - 11 September 2004, page 12

    Rethinking the names of every organism on the planet is a radical step
                      but it might be worth the upheaval

        A BAND of renegade biologists is taking on a mammoth task that
    threatens to upset a status quo that has been unchallenged for almost
      250 years. Put simply, they want to change the way scientists name
                     every living organism on the planet.

    These rebels say that our system of naming plants, animals, fungi and
      bacteria, famously introduced by Linnaeus in 1758, is frustrating
    efforts to understand the living world. They want to replace it with a
                more rational scheme they call the PhyloCode.

     Critics have slammed their proposal, arguing that it will be a waste
    of time and effort that will hinder the urgent task of cataloguing the
    thousands or even millions of as yet undiscovered species before they
        go extinct. It could also compromise laws designed to protect
        biodiversity, placing endangered species at unnecessary risk.

     Linnaeus developed the now familiar binomial system of nomenclature,
    in which the name of each species includes its genus. This identifies
    Homo sapiens, for example, as a member of the genus Homo. That system
     has since been expanded, so that every identified living species is
    also placed in a hierarchy that stretches from phylum at the top, down
     through class, order, family and genus. For instance, the genus Homo
    belongs to the family Hominidae, which is part of the order Primates,
    which in turn belongs to the class Mammalia, which is a member of the
                               phylum Chordata.

         Because this scheme sorts organisms loosely into just a few
     hierarchical divisions, it tells us relatively little about how they
      are related in evolutionary terms. And that, advocates of the new
       naming scheme say, is hindering our understanding of the natural
     world. "The whole endeavour of trying to understand and communicate
     about the diversity of life is being compromised by a naming system
    that is outdated and has bad consequences," says Michael Donoghue, an
                  evolutionary biologist at Yale University.

    Under the Linnaean system, a taxonomist who wishes to name a group of
    organisms must also assign that group a rank, such as genus or family.
       But there are not enough of these to cope with the increasingly
     complex branching of the evolutionary tree now being discovered. To
       keep up, taxonomists have been inventing a confusing raft of new
           ranks, such as phalanxes, infracohorts and supertribes.

    Even worse, biologists who identify a new group may find they have to
     change the ranks - and therefore the names - of several other groups
      in order to maintain some semblance of consistency. This, Donoghue
    claims, discourages people from naming groups as they are discovered,
     and thus limits the progress we can make in our understanding of how
       different groups of animals or plants are related to each other.

    For example, Donoghue and his colleagues have recently discovered that
    the genus Potentilla, which belongs in the rose family, does not form
    a natural evolutionary group, technically known as a clade. A clade is
     made up of an ancestral species and all its descendants; think of it
    as that part of an evolutionary tree that would fall off with a single
                                   saw cut.

       One subset of Potentilla does form a clade, but other Potentilla
      species arise elsewhere in the tree, while plants placed in other
     genera lie on intermediate branches. To fix the problem, taxonomists
      would either have to group these other genera within Potentilla -
    which would mean renaming hundreds of species, including familiar ones
    such as the strawberry - or restrict the name Potentilla to members of
    the smaller clade and find new genus names for the rest. Either option
    involves a huge amount of work shuffling species in and out of genera.

    The PhyloCode would eliminate the need for that by abolishing genera,
      families and every other rank above the level of species. Instead,
    taxonomists would be free to define and name any clade they discover.
        Donoghue's team could assign a name to the clade they found in
     Potentilla, but they would be under no obligation to name or rename
    any other clades at the same time. That will allow naming to track our
      understanding of biodiversity more closely, says Philip Cantino, a
                    botanist at Ohio University in Athens.

       Cantino and Kevin de Queiroz, a lizard expert at the Smithsonian
     Institution in Washington DC, have drafted a set of rules governing
     PhyloCode names ([11]www.ohiou.edu/phylocode). At a meeting in Paris
    in July, PhyloCode proponents began the task of applying this code to
     the Earth's living things. The meeting will form the basis of a book
        to be published in two or three years' time that will mark the
      official beginning of PhyloCode names - "the way Linnaeus was the
          starting point for the other codes," as Donoghue puts it.

    Though the new system will change the way taxonomists name organisms,
      PhyloCoders hope that everyone else - even other biologists - will
     notice little difference. Today's familiar names should still apply.
      Humans, for example, would be a species called sapiens in a clade
    called Homo, so we would continue to call ourselves Homo sapiens. The
    only change is that the clade would no longer have the rank of genus.

     As innocuous as it sounds, the idea has provoked angry protests from
                              most taxonomists.

     Taxonomists, already thin on the ground, are frantic to catalogue as
      much of the world's biodiversity as they can before it disappears.
      "We're the last generation that will have access to this enormous
     diversity of species, and to piddle away our time implementing a new
    system is a tragic waste," says Quentin Wheeler, an insect taxonomist
                  at Cornell University in Ithaca, New York.

        The implications are more than just academic. The machinery of
        conservation, from laws like the US Endangered Species Act to
    international agreements such as the Convention on International Trade
       in Endangered Species, is based on the existing system of names.
       "Trying to change that system of naming right now would be utter
    chaos," says John Kress, a botanist at the Smithsonian Institution who
      works extensively with government agencies on biodiversity issues.
      Savvy traders in endangered species would be quick to exploit any
     ambiguities during the changeover, says Dennis Stevenson of the New
     York Botanical Garden, who serves on the cycad specialist group for
                     the World Conservation Union (IUCN).

     Donoghue concedes that the transition may bring some uncertainties.
     "The prudent thing to do is to experiment with this," he says. "Then
       we'll understand the pros and cons much better and we can either
    modify things or decide not to do it at all. But my guess is that once
        we've done the experiment we'll end up strongly preferring the
    PhyloCode." Given the hostile reception PhyloCode has received so far,
                     they have a lot of convincing to do.

                                  Bob Holmes


   11. http://www.ohiou.edu/phylocode

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