A glimpse of the first 30,000 entries of an ambitious online "Encyclopedia of Life" were unveiled Tuesday, the start of a project scientists hope will eventually catalogue all 1.8 million known species of life on Earth.

The $100 million US initiative, spearheaded by an international group of museums, universities and labs, began in 2007 and is to be completed by 2017.

The free online encyclopedia will officially launch on Wednesday at a conference in Monterey, Calif.

So far, it has 25 fully completed entries that include text, video and pictures, as well as 30,000 entries with less detailed information.

The website is designed to act as a microscope in reverse, or "macroscope," to help researchers understand large-scale patterns that their specialized research might otherwise miss.

Such a large-scale view could provide insight into the impact of climate change and the spread of human disease; bolster efforts to slow the spread of invasive species; or aid research into longevity, the group behind the project said in a statement Tuesday.

Aim of encyclopedia is to help conservation efforts

But the main purpose of the site will be to provide a resource to aid conservation efforts.

The encyclopedia will have a great impact on the scientific community, said Harvard biologist Edward Wilson, whose call for a portrait of life in a 2003 speech helped spur the project.

"It aims not only to summarize all that we know of Earth's life forms but also to accelerate the discovery of the vast array that remain unknown," said Wilson in a statement.

"This great effort promises to lay out new directions for research in every branch of biology."

Feedback on the first 30,000 entries of the website will ultimately shape its final design, the encyclopedia's creators said.

The website is a joint project of the Smithsonian Institution, Harvard University, Chicago's Field Museum, the Marine Biological Laboratory in Massachusetts, the Biodiversity Heritage Library Consortium, the Missouri Botanical Garden and the Atlas of Living Australia.