ARKive : Images of Life on Earth - The Noah's Ark for the Internet era. A global initiative gathering together films, photographs and audio recordings of endangered species from round the world.
Biodiversity Explorer - Classification of all forms of life, with some photos. Has a strong South African emphasis.
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.
BioLib - Taxonomic tree of plants and animals with a photo gallery and some checklists for the Czech Republic and Slovakia. In Czech and English.
BiologyBase - Checklists, articles, and links for the world of life.
Census of Marine Life - A global network of researchers engaged in a ten-year initiative to assess and explain the past, present, and future diversity, distribution, and abundance of marine life in the oceans.
Classification of Living Things - An introduction to the naming and relationships of living things. Classification involves much human judgement and is in a constant state of flux as new information is discovered.
Clear Mind Photos - Photographs by Philip Goddard of insects, other invertebrates, wild flowers, lichen, fungi and some birds and mammals.
Discover Life - Information about taxonomy, natural history, distribution, abundance, and ecology of many species worldwide. Includes tools to identify, map, and database species.
Dr. PI bloobook - Multilingual weblexicon for animals, plants, fungi, bacteria and other organisms of the world, covering more than 5000 species.
Encyclopedia of Life - A new project to create an online reference source and database for every one of the 1.8 million species that are named and known on this planet. Includes FAQ and press resources.
Families - Introduction to the classification of plants and animals from the Franklin Institute, with links to many groups of living organisms.
GlobalTwitcher.com - Database covering the flora and fauna of the world with a checklist for each country.
HabitasOnline - Information on the plants, animals, and fossils of Ireland. Includes an encyclopedia of marine life of the UK. From the Ulster Museum Sciences Division.
iSpecies - A species search engine from Rod Page of Glasgow University. Search on either the common or Latin name of a species. Results are generated by querying other data sources.
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.
Mikko's Phylogeny Archive - A compilation of various phylogenetic trees representing different views of taxonomy. Includes links to other taxonomic websites.
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.
Natural Selection - A gateway to quality, evaluated Internet resources in the natural world co-ordinated by The Natural History Museum, London.
Nature of New England - Photos, facts, and links to information about birds, butterflies, mammals, and wildflowers of this region.
NCBI Taxonomy - Searchable and browsable taxonomy tree of organisms for which there are publicly available gene sequences.
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.
Thomson: Free Resources - Includes the Index to Organism Names, a publicly available subset of TRITON the Taxonomy Resource, and the Zoological Record Thesaurus.
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.
Tree of Life Web Project - Collaborative effort of biologists from around the world, providing information about the diversity of organisms on Earth, their evolutionary history (phylogeny) and characteristics.
Utah Conservation Data Center - Database of photos and fact sheets for animals and plants occurring in this state. Includes lists of sensitive, threatened, and endangered species.
Wikispecies - Wikimedia Foundation project that aims to catalog all species.
Willi Hennig Society - Society of cladisticians, publishes the journal "Cladistics"
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.