01 September 2008

Splitters and Lumpers: why planet Earth needs taxonomists

"Whazzat?" is a question we often exclaim when exploring our shores.
Unidentified sea anemone
Here's more about how lifeforms on our planet get named, the difficulties and why this effort is important.

Splitters and Lumpers: why planet Earth needs taxonomists
Marlowe Hood, Yahoo News 31 Aug 08;

Among biological scientists, they are the true nomenklatura, a small and far-flung tribe dedicated to the coherent naming of all living things, past and present.

Gathered in Paris last week, the world's leading taxonomists feted the brilliant and vainglorious Swedish naturalist who, 250 years ago, single-handedly created the system of classification they still use.

But beneath the festive air the proceedings were troubled, on at least two counts.

Carl Linnaeus -- who called the sample-collecting students he dispatched across the globe in the 18th century his "apostles" -- was a creationist born a century before Charles Darwin.

Today many biologists are clamouring for a new approach to cataloging the planet's flora and fauna that goes beyond morphology and takes evolution into account.

A dozen competing theories have cropped up in the last decade, and at least one of them, called PhyloCode, has gained serious traction.

In other scientific disciplines, new ideas elbowing out old ones is a normal and essential process. But in taxonomy, renewal poses a special problem: how can you replace plant and animal names used for two-and-a-half centuries without causing chaos?

"If we did not have a system of classification that was hierarchical and had names that could be easily retrieved we would be helpless," American biologist Edward O. Wilson explained in an interview.

Taxonomists themselves can poke fun at their sometimes arcane bickering as to whether a new discovery is a species in its own right or a subset of one already on the books.

"We have 'lumpers' and 'splitters'," said Richard Pyle, a zoologist and fish specialist at the Bishop Museum in Hawaii, and an officer in the International Commission on Zoological Nomenclature (ICZN).

"Splitters want to draw the lines around a specimen tightly, while lumpers will say, 'no, that's just a slight variation'. And there is nothing in this system which tells you who is right -- it is purely subjective," he said.

But beyond growing internecine quarrels, an even deeper and shared malaise coursed through the proceedings.

It stemmed from a gnawing sense of urgency, and realisation that what Wilson calls "the great Linnean enterprise" -- the mapping of the Earth's entire biosphere -- has barely begun.

Amid predictions that the impact of human activities -- especially climate change -- could wipe out thirty percent or more of all species on Earth by century's end, the scientists charged with finding and defining those species are feeling the heat.

"If you want to preserve a vanishing species, or combat a medically dangerous one, or use it in some beneficial way as a crop, you need to know what you are dealing with," said Andrew Polaszek, a scientist at the Natural History Museum in London and outgoing Executive Secretary of the ICZN.

"That name is the key to all the knowledge that has been accumulated about that organism."

While most people might assume that the job of cataloging Earth's living organisms is nearly complete, the opposite is true.

Some 90 percent of bird species are known, more than 80 percent of flowering plants. But scientific understanding of bacteria and other micro-organisms is "shockingly incomplete," said Wilson, a towering figure in the field of biology, and one of the first to probe the concept of biodiversity.

"Two hundred and fifty years after Linnaeus, we have still only classified as few as 10 percent of the organisms living on Earth," he said.

There are an estimated 1.5 million types of fungi, but only 60,000 are known. Nematodes, including parasitic pinworms and hookworms, comprise the most abundant phylum in the animal kingdom -- probably four or five million strong -- but only 80,000 have been classified.

"In dealing with the living world, we are mostly flying blind," said Wilson. "Trying to diagnose the health of an ecosystem -- a lake or a forest -- to save or stabilise it is like a doctor treating a patient while only knowing ten percent of the organs."

In an effort to catapult the current classification system into the 21st century, a number of taxonomists have launched Zoobank, a Web-based registry of organism names. Some 1.8 million species are listed so far.

"The registry will be the central place where everyone can go look to see what is going on in the rest of the world," said Pyle, who described it as the "most profound change in taxonomy since Linnaeus."

But even this seemingly common-sense step has created controversy, pitting advocates of Internet-based, open-access publishing against traditional and powerful publishers.

Under the current system, a new species does not officially exist until the scientific report of its discovery appears in print.


Other posts about tricky naming issues

The perils of morphology and taxonomy on the wildfilms blog

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