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Linnean naming system faces challengers
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.
Loosely sorted
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of trying to understand and communicate about the diversity of life is being compromised by a naming system that is outdated and has bad consequences," says Michael Donoghue, an evolutionary biologist at Yale University.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.
Changing ranks
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.
No obligation
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. 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.
Tragic waste
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
http://www.newscientist.com/news/news.jsp?id=ns99996369
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.
Loosely sorted
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.
Changing ranks
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.
No obligation
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. 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.
Tragic waste
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
http://www.newscientist.com/news/news.jsp?id=ns99996369
I love all things Linnaean!
