The Green Pages: scientists put all creatures great and small into 'telephone book of life'

A project that is attempting nothing less than to compile a list of every living organism on Earth is making what it describes as "spectacular progress" in a world which is still discovering scores of new species every week.

A project that is attempting nothing less than to compile a list of every living organism on Earth is making what it describes as "spectacular progress" in a world which is still discovering scores of new species every week.

The Catalogue of Life has just logged its 500,000th species, which may sound a lot, but the partly British-led project has a long way to go. Around 1.75m species have been identified somewhere on Earth, and this is a fraction of the estimated total. Even the most conservative experts put the number at five million, and some say that as many as 10 times as many different species may inhabit the land, seas and skies.

It is this colossal hole in human knowledge that the Catalogue of Life programme addresses. It began in 2001 as a joint venture between Species 2000, based at the University of Reading, and ITIS, based at the Smithsonian Institution in Washington, and aims to complete the listing of life on Earth by 2011. Speaking from the project's annual conference in Malta yesterday, one of its founders, Professor Frank Bisby of Reading University said: "It is like a telephone book listing all organisms and where they can be found. It is the whole-Earth equivalent of the Human Genome Project."

The Catalogue of Life programme is part of an international effort to chart biodiversity being made by organisations such as Global Biodiversity Information Facility in Copenhagen, with which it co-operates. It will not give detailed biological information but, Professor Bisby says, it will be "the master index for our planet" and will, in time, link to more in-depth material. It is compiled via partnerships with databases and experts worldwide, who undertake to provide definitive species lists. World-famous organisations such as the Natural History Museum and the Royal Botanical Gardens, Kew, are involved; so too are specialised operations such as the 11,000-species-strong Antbase in the US, and similar collections for fish in the Philippines, for bacteria in Japan, and for ticks in the Netherlands. Partners include a retired bank IT manager from Belgium, who is the world's leading expert on scarab beetles.

To compile their lists, the researchers have to unravel the knots of identification and naming in each field. Many species, for instance, have several scientific names (quaking aspen, a tree, has had more than a dozen), and someone has to decide which is the right one or whether there are differences that constitute separate species.

The experts also have to keep track of new discoveries, which are being made at an astounding rate. Thousands of new insects, about 2,000 flowering plants and 10-15 birds are identified every year, and the Marine Census says it finds an average of two new fish species a week. In the past few years, a purple frog, a leaf deer and even a new elephant have come to light. In the first 10 weeks of this year, 31 new species were reported - and that was just in the non-scientific press. They included new species of fairy shrimp, catfish, coral, three right whales, an eel and two lemurs.

But it is among the smallest of creatures and organisms that most work remains to be done. While 45,000 of the estimated 50,000 vertebrates have been discovered, only 1 per cent of the estimated 400,000 viruses, an even smaller proportion of likely bacteria, and a mere 800,000 of the estimated eight million insects have been named.

The skills needed to identify species are rare - there are only around 10,000 taxonomists in the world. The last complete study of rove beetles, for instance, was in 1840, and only 10,000 of the world's estimated 80,000 millipedes have been discovered. Shame, then, that there were until recently a mere five experts on them worldwide. As Sandy Knapp, a botanist at the Natural History Museum, said: "There are whole families of plants for which there are no world experts."

Efforts are being made to get more funding into taxonomy and train more of these threatened professionals. After all, it would be a supreme irony if our attempts to chart life on Earth were hampered because the humans with the expertise to identify our more obscure species became extinct.

NEW SPECIES ON THE BLOCK

Leaf deer (Muntiacus putaoensis)

A rare case of a new terrestrial mammal, this barking deer was found in Burma in 1997. The smallest deer in the world, it stands just 20in high

Blue-flecked finch (Amaurospiza carrizalensis)

This was found two years ago in Venezuela by a survey conducted shortly before its only known habitat - spiny bamboo - was destroyed

Calayan rail (Gallirallus calayanensis)

This bird, with its bright orange-red legs and beak, was discovered living by a stream in a remote part of the northern Philippine island of Calayan

Purple frog (Nasikabatrachus sahyadrensis)

Not just a new species, this - found in India two years ago - is a whole new family of burrowing frogs

Goby fish (Amblyeleotris katherine)

Found off Guam, this lives in partnership with a snapping shrimp that digs a shelter which both share

Fruit fly (Drosophila mojavensis)

Evolution before our eyes. Researchers believe this US fly and a close relative are becoming separate species