Information by Group
Biodiversity Heritage Library -- "Free access to hundreds of thousands of volumes, comprising over 58 million pages," from the 15th century to the present. Read more about the BHL, including their taxonomic names, tools and services, data exports, and other tools that will help you. More information on the FAQ, including finding images and reusing content.
Encyclopedia of Life -- A central search hub for information about "animals, plants, fungi, protists and bacteria, [which is] scattered around the world in books, journals, databases, websites, [and] specimen collections." Shows food webs (who eats whom), and more. Hosted by the Smithsonian's Museum of Natural History.