Encyclopedia of Life, Fossil Mysteries, NatureServe Explorer

International Year of Biodiversity

In a few words from Wikipedia..."The Encyclopedia of Life (EOL) is a free, online collaborative encyclopedia intended to document all of the 1.8 million living species known to science."

Encyclopedia of Life [Wikipedia]

Here are two other sources...

Fossil Mysteries

Fossil Mysteries, a highly interactive exhibition, explores big themes in science: evolution, extinction, ecology, and Earth processes. Abundant fossils, models, murals, and dioramas offer unique multi-sensory experiences. You'll see the world—past and present—in a whole new way.

NatureServe Explorer

NatureServe is a non-profit conservation organization whose mission is to provide the scientific basis for effective conservation action. NatureServe and its network of natural heritage programs are the leading source for information about rare and endangered species and threatened ecosystems.