The field guide for citizen scientists, which aims at bringing all species on the planet together, has reached the 750,000 milestone

An ambitious attempt to create an encyclopedia of every known species on Earth has reached a major new milestone.

The Encyclopedia of Life (EoL), a free and collaborative website, said on Monday it now has pages for each of 750,000 species, meaning more than one-third of all the planet's 1.9m species are now covered.

"EoL is the ultimate online field guide for citizen scientists," said Jennifer Preece, dean of the College of Information Studies at the University of Maryland. "There are many online sites dedicated to specific groups of species such as insects, birds or mammals. Not since Noah, however, has there been an effort like this to bring all the world's species together."

The site uses content from 180 partners to bring together images, videos and scientific information, including 35m pages of scanned literature created by the Biodiversity Heritage Library. The new site allows members to create their own collection of species.

"The virtual collections put life into meaningful contexts from scholarly ones such as Invasive Insects of North America or Endangered Birds of Ecuador to personal collections such as A Checklist of Trees in My Backyard. Only imagination and energy limit the possibilities," said Jesse Ausubel, vice president of the Alfred P Sloan Foundation which helps fund the EoL.

The EoL's directors say they want it to become a microscope in reverse, or "macroscope", helping users discern large-scale patterns. By aggregating information for analysis, they say the EoL could, for example, help map vectors of human disease, reveal mysteries behind longevity, suggest substitute plant pollinators for a growing list of places where honeybees no longer provide that service, and foster strategies to slow the spread of invasive species.

Founded in 2007, the EoL had 30,000 species pages by the beginning of 2008, making the new version a huge expansion. Renowned the Harvard University biologist Edward O Wilson, one of the driving forces behind the EoL, said the new site "opens EoL's vast and growing storehouse of knowledge to a much larger range of users, including medicine, biotechnology, ecology, and now increasingly the general public".

The EoL has more than 1m more pages in place awaiting content from partners and members. But a recent estimate concluded that there are a total of 8.7m species on Earth, excluding bacteria and viruses, suggesting many more pages will need to be added to EoL in the future.