BiologyBase Checklists, articles, and links for the world of life. http://www.biologybase.com/

Integrated Taxonomic Information System Authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world. http://www.itis.usda.gov/

World Biodiversity Database A growing taxonomic database and information system that aims at documenting all presently known species (about 1.7 million). Taxonomic trees, descriptions, synonyms, literature citations, and molecular database queries. http://www.eti.uva.nl/Database/

BioImages - Virtual Fieldguide for UK Biodiversity Large selection of pictures of organisms, mostly British in origin. Images are an aid to identification, showing different stages, states and views of the organisms. Search the database or follow a taxonomic tree. http://www.bioimages.org.uk/

Biodiversity Explorer Classification of all forms of life, with some photos. Has a strong South African emphasis. http://www.museums.org.za/bio

Tree of Life Phylogenetic tree with information about the diversity of organisms on Earth, their history, and characteristics. An on-going multi-authored project hosted by the University of Arizona. http://tolweb.org/

Natural Perspective Dedicated to the beauty and science of nature and to the joys nature brings to those who explore it. The material here is organized according to the biological principles of Taxonomy. http://www.perspective.com/nature/index.html

Discover Life Information about taxonomy, natural history, distribution, abundance, and ecology of many species worldwide. Includes tools to identify, map, and database species. http://www.discoverlife.org/

ARKive Non-profit initiative of The Wildscreen Trust with photographs, movie clips, sound recordings, and brief desriptions of selected endangered and protected species of Britain and the rest of the world. http://www.arkive.org/

BIOSIS Resources Includes the Index to Organism Names, a publicly available subset of TRITON the Taxonomy Resource, and the Zoological Record Thesaurus. http://www.biosis.org.uk/free_resources/

Natural Selection A gateway to quality, evaluated Internet resources in the natural world co-ordinated by The Natural History Museum, London. http://nature.ac.uk/

Kingdoms Project Project to establish web-based databases of organisms and other natural sciences subjects. Includes information about some taxonomic groups. http://www.il-st-acad-sci.org/kingdoms.html

Lepidoptera and Other Life Forms Taxonomic tree of mammals, insects, birds, and plants. Includes common and scientific names, publication details, references, links, general range maps, and some images. Most complete for Lepidoptera. http://www.funet.fi/pub/sci/bio/life/intro.html

NCBI Taxonomy Searchable and browsable taxonomy tree of organisms for which there are publicly available gene sequences. http://www.ncbi.nlm.nih.gov/Taxonomy/taxonomyhome.html/

Canadian Version of Integrated Taxonomic Information System Searchable database of four kingdoms: plant, animal, fungi, monera. Search by scientific or common names, English or French. http://sis.agr.gc.ca/pls/itisca/taxaget?p_ifx=aafc

Mikko's Phylogeny Archive A compilation of various phylogenetic trees representing different views of taxonomy. Includes links to other taxonomic websites. http://www.fmnh.helsinki.fi/users/haaramo/index.htm

Flora and Fauna of the Great Lakes Provides access to materials from the fish, mammal, and fungus collections of the University of Michigan, USA. Includes many images of specimens. http://www.lib.umich.edu/programs/greatlakes/

Survey of the Plant Kingdoms Explores plant anatomy, taxonomy, and classification, from Monera through the higher plants. Includes descriptions as well as graphics and schematics. http://home.manhattan.edu/~frances.cardillo/plants/intro/

BioLib Taxonomic tree of plants and animals with a photo gallery and some checklists for the Czech Republic and Slovakia. In Czech and English. http://www.biolib.cz/

Human Genome Sequencing Center Search Launcher On-going project to organize molecular biology-related search and analysis services available online by function, providing a single point-of-entry for related searches - from Baylor College of Medicine. http://searchlauncher.bcm.tmc.edu/