Scientists have named about 1.8 million species – including new discoveries such as the clouded leopard and a Tanzanian monkey. But as Zoe Cormier reports‚ that leaves about 90 per cent of life on the planet a mystery. One big hitch? Defining what exactly makes a species a species
Ten years ago‚ Harvard naturalist Edward O. Wilson estimated that 30‚000 species were going extinct every year. Now‚ scientists are taking an even darker view. According to the World Conservation Union’s latest Red List‚ a staggering one in eight birds‚ one in four mammals and one in three amphibians are threatened with annihilation. And by the end of the century (because of climate change) species could disappear at 10‚000 times the natural rate.
But thousands of new species are also being identified each year. A case in point: the clouded leopard of Borneo and Sumatra. This spring‚ biologists examined the DNA of the 40–pound‚ three–foot predator for the first time in 100 years. Previously thought to be members of the same species as clouded leopards from mainland Asia‚ they found that the Borneo feline has at least 40 unique genetic traits – which makes the two cats as different as lions are from tigers.
Borneo‚ in fact‚ is a hotbed of biological discovery. Like the Amazon and the African Congo‚ the “Heart of Borneo” – a plot of rain forest the size of Kansas – is unusually diverse. On 9.7 hectares‚ for example‚ there are about 700 different species of trees‚ as many as exist in all of North America. And in 2006 alone‚ scientists identified 30 new species of fish‚ 16 species of ginger‚ two tree frogs and three new trees in Borneo’s rain forest.
Meanwhile‚ collections manager William Stanley and his colleagues at the Field Museum in Chicago not only discovered a new species – they identified an entirely new genus. Originally‚ scientists classified the kipunji monkey as a kind of mangabey. Then a Tanzanian farmer found one of the monkeys (formerly seen only in photos) dead in a trap. Closer analysis revealed that it was the first new African monkey genus described in 80 years. “It was mind–blowing‚” says Mr. Stanley of his team’s 2005 findings.
And yet discoveries like these merely scratch the surface of life on the planet. In all‚ researchers have named about 1.8 million species – which leaves five million to 30 million species unclassified. Or‚ depending on where in that broad range scientists stake their claims‚ 90 per cent of species to go.
Of course‚ part of the problem is simply finding species that live deep in the ocean‚ on inaccessible land or in erratic (read: elusive) habits. But there is also another big hurdle to cataloguing even the species already known to exist – the tricky nature of taxonomy.
The question of exactly what makes a species a species is a hotly debated topic among evolutionary biologists. The widely accepted definition is that if two creatures can breed and produce fertile offspring‚ then they are members of the same species. For instance‚ horses and donkeys can breed‚ but their offspring – mules – are sterile. Hence‚ donkeys and horses are different species.
But this rule of thumb doesn’t always ring true. Lions and tigers‚ for example‚ can occasionally produce fertile young. And plants and life forms such as bacteria interbreed all the time. “We’ll never have one universal criterion by which all specimens may be unambiguously placed in a single species‚” says Daniel Brooks‚ a parasite taxonomist at the University of Toronto.
Nonetheless‚ Prof. Brooks has personally identified hundreds of new species (he admits he lost count a long time ago). “If I’ve got four or five traits that are different‚ then I feel better about saying this is a new species‚” he says.
But it’s a slow process. It can take years of scrutinizing the creature’s anatomy and comparing it with everything else known to science in order to figure out if something truly distinct has been found. Until then‚ specimens have been known to sit in drawers for more than 50 years before being identified as a new species.
However‚ a new genetic test known as “DNA barcoding” is helping to speed things up. Developed at the University of Guelph by evolutionary biologist Paul Hebert‚ the test allows scientists to quickly –– and cheaply –– create a numerical “barcode” for a species.
The test works by giving a gene known as CO{–1} (found in slightly different forms in all living things) a numerical code about 650 digits long. This can then be easily compared to other species’ “barcodes” for that same gene. A match of 97.5 per cent or less between two specimens generally indicates that they are different species.
Using this method‚ Prof. Hebert and his colleagues found 15 previously unknown North American bird species when they sorted through the 690 known species. In total‚ “we’ve probably revealed about 3‚000 overlooked species‚” he says.
Scientific curiosity aside‚ however‚ exactly why should we go to the trouble of logging every species on Earth? Does it really matter if we know the name and identity of every bug‚ every slime mould‚ every parasitic worm?
“Most people don’t lie awake at night and worry about the species count of the planet – but they do worry about where their tax dollars are spent‚” Prof. Hebert says. We spend billions every year on controlling pest species‚ and combatting the bacteria and viruses that make us sick. The wrong information can mean wasting money trying to kill the wrong insect. Or it could kill a patient by misdiagnosing an illness.
Classification is also key to conservation. For example‚ now that the clouded leopard – Borneo’s top predator – is considered a separate species‚ World Wildlife Federation representatives say it will emphasize the importance of preserving the “Heart of Borneo” – perhaps bolstering an agreement reached in February by Indonesia‚ Malaysia and Brunei to take care of this unique stretch of land.
“No name‚ no information. It’s that simple and that critical. We have to know as many species as possible in order to make rational decisions about how to cope with environmental change‚” U of T’s Prof. Brooks says.
“Unfortunately‚ we’re probably naming new species slower than new species are going extinct.”
YETI CRAB
Official name
Kiwa hirsuta
Official coming out
March‚ 2006
Like many new species‚ this one was found deep in the ocean – 2‚300 metres down‚ to be exact‚ near a hydrothermal vent in the south Pacific. And like most deep–sea animals‚ its a weird one: It has almost completely lost its eyes‚ its claws are covered in blond hairs (hence its nickname)‚ and living in those hairs are bacteria‚ whose purpose remains a mystery. The creature is so unlike any lobster or crab seen before that researchers have placed it in a new family called kiwaidae.
THE SMALLEST FISH
Official name
Paedocypris progenetica
Official coming out
January‚ 2006
Biologists first collected specimens of this fish from the acidic peat swamps of Sumatra more than 10 years ago. But before publishing their findings‚ they wanted to be sure that it wasn’t just a new species‚ but also the smallest fish in the world – beating out the 1.2 centimetre–long dwarf goby. Measuring less than eight millimetres‚ this distant relative of the carp is‚ in fact‚ the planet’s smallest known creature with a backbone.
SNUBFIN DOLPHIN
Official name
Orcaella heinsohni
Official coming out
July‚ 2005
The first new dolphin species to be discovered since 1956‚ the snubfin was previously thought to be a kind of irrawaddy‚ a grey and white dolphin that lives along the coasts and estuaries of Australia and southeast Asia. But researchers had long suspected that they may be a new species‚ because of their unique coloration (white‚ brown and dark grey). They used DNA–typing methods to confirm their hunch.
ROCK RAT
Official name
Laonastes aenigmamus
Official coming out
May 2005
American scientists first encountered the kha–nyou (or rock rat) in the late 1990s on sale as bush meat in rural markets in Laos. And it has still not been seen alive by biologists. With a rat–like body about a foot long and a bushy tail like a squirrel‚ the rodent seemed to defy classification. Biologists at first placed it in an entirely new family. Now‚ however‚ it seems that the rock rat is actually a member of a family of rodents thought to be extinct – making it the latest example of the “Lazarus effect‚” a species that appears to have come back from the dead.
Classification 101
Domain‚ kingdom‚ phylum‚ class … Remember these terms from junior high school biology? All life on Earth can be organized based on this system – which dates back to the work of 18th–century Swedish naturalist Carolus Linnaeus. He recognized that different organisms could be grouped based on shared characteristics. As for the sticky details (and the endless designation of subfamilies and suborders and subphyla)‚ that continues to be a controversial topic among academics. Still‚ this system of classification has been used for hundreds of years as a consistent way to take any species and slot it into the tree of life. Take the clouded leopard of Borneo:
Species: Neofelis diardi – Bornean clouded leopard
Genus: Neofelis – all clouded leopards
Family: Felidae – all cats
Order: Carnivora – dogs‚ cats‚ seals‚ bears and other carnivores
Class: Mammalia – all mammals
Phylum: Chordata – all creatures with some kind of backbone‚ including all vertebrates and a few invertebrates
Kingdom: Animalia – all animals‚ as opposed to plants or fungi‚ etc.
Domain: Eukarya – creatures possessing cells with membrane–bound organelles‚ as opposed to prokarya such as bacteria