A worldwide scientific effort to catalog every living species has topped the 1 million milestone. Six years into the program the total has reached 1,009,000, researchers report. They hope to complete the listing by 2011, reaching an expected total of about 1.75 million species.

Thomas M. Orrell, a biologist at the Smithsonian's National Museum of Natural History, said the finished catalog will include all known living organisms, from plants and animals to fungi and microorganisms such as bacteria, protozoa and viruses.

"Many are surprised that, despite over two centuries of work by biologists and the current worldwide interest in biodiversity, there is presently no comprehensive catalog of all known species of organisms on Earth," Orrell said.

The listing does not include fossil species from the past.

The Integrated Taxonomic Information System-Species 2000 Catalog of Life provides access to data maintained by a variety of scientific organizations, each specializing in a certain area.

For example, information on dipteran flies is maintained by the Agriculture Department's Systematic Entomology Laboratory at the Smithsonian's National Museum of Natural History.

Natural history museums in London, the Netherlands and New York maintain clothes moth, dragonfly and spider data. Experts in Canada and Paris keep the data on Ichneumon wasps and longhorn beetles.

These lists are peer-reviewed and checked technically, and then integrated into special software for the catalog.

The project, involving some 3,000 biologists, is led by Frank Bisby of the University of Reading in England and Orrell.