• Status and Trends of the Nation's Biological Resources (USGS)
• Wild Species 2000: The General Status of Species in Canada
• NatureServe (formerly known as the Association for Biodiversity Information)
• NatureServe Explorer: an online encyclopedia of life
• All Species Homepage
• Audubon Online Field Guides (eNature.com)
• Biodiversity and Biological Collections Web Server
• Biological Abstracts and the Zoological Record (BIOSIS)
• Biological Control: A Guide to Natural Enemies in North America
• Center for Aquatic and Invasive Plants (Univ. of Florida)
• Earth Trends - The Environmental Information Portal (World Resources Institute)
• Ecology, Biodiversity and the Environment: Virtual Library
• eNature.com - Bringing Nature to Life (National Wildlife Federation)
• Endangered Species Home Page (USFWS)
• Fish & Wildlife Information Exchange
• Florida Museum of Natural History
• Hawaiian Biological Survey Web Site
• Information Center for the Environment
• Illinois Natural History Survey
• National Atlas of the United States (USGS)
• National Museum of Natural History (Smithsonian Institution)
• Our Living Resources - A Report to the Nation on the Distribution, Abundance, and Health of U.S. Plants, Animals and Ecosystems
• State Biodiversity Database Survey
• The Web Lift to All Taxa (UCMP)
• Tree of Life Web Project
• UNEP-World Conservation Monitoring Centre
• U. S. Geological Survey - SEARCH
• World Species List - Animals, Plants, Microbes

Archaea:

• Introduction to the Archaea - Life's Extremists (UC - Berkeley)
• Extremophiles (Scientific American article)

Viruses:

• Introduction to the Viruses (UC - Berkeley)
• All the Virology on the WWW
• The Big Picture Book of Viruses
• Virus Databases Online
• Index Virum
• Plant Viruses Online
• WWW Virtual Library: Microbiology and Virology

Protists:

• Tree of Life - Protista
• The Algae World Wide Web Site (NMNH, Smithsonian)
• Welcome to the World of Algae
• Introduction to the "Green Algae" (UCMP)
• The Diatom Collection of the California Academy of Sciences
• Great Lakes Diatoms
• The Euglenoid Project
• Checklist of Phytoplankton in the Skagerrak-Kattegat (N Atlantic Ocean)
• Protist Image Page
• Introduction to the Radiolaria
• Radiolaria.org
• Zoosporic Fungi Online

Fungi:

• Tree of Life - Fungi
• Fungi Collections of Centraalbureau voor Schimmelcultures (CBS) (The Netherlands)
• Introduction to the Fungi (Univ. of California - Berkeley)
• Introduction to the Fungi (Univ. of Hawaii at Manoa)
• Michigan Fungal Bioinformatics Project
• Mycological Resources on the Internet
• Systematic Botany and Mycology
• Mycorrhiza Information Exchange
• Taxonomy of Fungi in Glomales (Arbuscular Mycorrhizal Fungi)
• The Lichen Home Page (NMNH, Smithsonian)
• Checklists of Lichens (Worldwide)
• Fun with Lichens
• Fact Sheets on Norwegian Lichens

Plants:

• PLANTS (NRCS)
• Tree of Life - Green Plants
• A Survey of the Plant Kingdoms
• Botany Navigator (Univ. of Hawaii at Manoa)
• Botany for the Next Millenium (article)
• Index to American Botanical Literature (New York Botanical Garden)
• Internet Directory of Botany
• Systematic Botany and Mycology

• BIOMAPS - Biodiversity Mapping for Protection and Sustainable Use of Natural Resources
• Bryophytes - Mosses, Liverworts, & Hornworts
• Centres of Plant Diversity - The Americas
• The Cycad Pages
• Fairchild Tropical Garden Botanical Resource Center
• Flora of North America (FNA)
• GRIN Taxonomy
• Gymnosperm Database
• Native Plant Information Network (Lady Bird Johnson Wildflower Center)
• Natural Perspective
• Noble Foundation Plant Image Gallery
• North American Native Plant Society
• The Parasitic Plant Connection
• Plant Conservation Alliance
  • Celebrating Wildflowers
• Plant Talk
• Poisonous Plants Informational Database (Cornell University)
• Scott's Botanical Links
• Seaweed
• Silvics of North America (Agriculture Handbook 654, US Forest Service)
• State Floras & Atlases:
  • The Vascular Flora of Arkansas
  • CalFlora
  • Atlas of Florida Vascular Plants
  • University of Michigan Herbarium
  • Ozarks Regional Herbarium - Missouri
  • Native Wildflowers of the North Dakota Grasslands
  • The Pennsylvania Flora Project (Morris Arboretum)
  • South Carolina Plant Atlas
  • The University of Tennessee Vascular Plant Herbarium
  • The Texas Flora (Texas A&M Univ.)
  • Native Plants of South Texas
  • Atlas of the Flora of Utah
  • Flora of the Washington-Baltimore Area
  • Wisconsin Vascular Plants
• A Synonymized Checklist of the Vascular Flora of the United States, Puerto Rico, and the Virgin Islands
• TreeGuide: The Natural History of Trees
• Vascular Plant Image Gallery (Texas A&M Univ.)
• Vascular Plant Image Gallery (Albion College)
• Virtual Foliage (Univ. of Wisconsin)
• Weeds Gone Wild - Alien Plant Invaders of Natural Areas
• Midwestern Wetland Flora (USGS)
• Western Wetland Flora (USGS)
• Wildland Shrub Species of the United States and its Territories edited by John K. Francis (US Forest Service)

Animals:

• Tree of Life - Animals
• The Animal Diversity Web
• Biodiversity and Biological Collections Web Server
• Census of Marine Life
  • OBIS - Ocean Biogeographic Information System
• The Electronic Zoo - Animal Resources (NetVet)
• Internet Resources Guide to Zoology (BIOSIS)
• The Jason Project
• Journey North - A Global Study of Wildlife Migration
• Marine Species Index - Marine Biological Laboratory
• Zooarchaeology Home Page

Vertebrates:

• Amphibian Species of the World Database (Amer. Museum of Natural History)
• AmphibiaWeb
• Boreal Toad Homepage (USGS)
• FrogWeb (USGS)
• The Center for North American Amphibians and Reptiles
• Amphibians of Glacier National Park
• Florida Museum of Natural History - Herpetology
• Crocodilians: Natural History & Conservation
• Snakes of North America
• The Brown Tree Snake on Guam (USGS)
• The EMYSystem (World Turtle Database)
• EuroTurtle
• General Information on Sea Turtles and Threats to Their Survival
• FishBase - A Global Information System on Fishes
• Australian Museum Fish Site
• Florida Museum of Natural History - Ichthyology
• Index to Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates
• Species Identification and Data Programme (FAO Fisheries)
• Sharks
• Monterey Bay Aquarium
• OceanLink
• Biggest, Smallest, Fastest, Deepest: Marine Animal Records
• Gadus Associates' List of Fisheries Web Sites
• Desert Fishes Council
• StreamNet - Fish Data for the Northwest
• BIRDNET - The Ornithological Information Source (The Ornithological Council)
• Patuxent Bird Identification InfoCenter (USGS)
• Bird Population Studies (USGS)
• Bird Monitoring in North America (USGS)
• The North American Breeding Bird Survey 1966-1996 (USGS)
• Canadian Bird Checklist Program
• Birds of the Continental United States and Canada
• Wings of the Americas (The Nature Conservancy)
• Birder
• BirdSource - Birding with a Purpose
• Raptor Information System (USGS)
• DUCKDATA: A Bibliographic Database
• Discovery for Recovery: International Pintail Recovery Initiative
• Mammal Species of the World (NMNH, Smithsonian Inst.)
• Mammalian Species Online - Complete Systematic List of Accounts (Amer. Soc. of Mammalogists)
• BATCALL: Acoustic Call Library and Species Accounts
• Bat Conservation International
• Bat Population Database (USGS)
• Fruit Bats of the Old World - The Lubee Foundation
• Office of Protected Resources - Protecting the Nation's Marine Resources (NOAA)
• Grizzly Bear and Black Bear Ecology
• Monitoring Grizzly Bear Populations Using DNA

Invertebrates:

• Rotifer Systematic Database (Univ. Texas-El Paso)
• Recent and Fossil Bryozoans
• Coral Health and Monitoring Program (NOAA)
• Coral Reefs - Magnificent Creations of Nature (The Coral Reef Alliance)
• The Global Coral Reef Alliance
• The Echinoids (The Natural History Museum - London)
• SCAMIT: Southern California Association of Marine Invertebrate Taxonomists
• Selected Sources of Information on Mollusks (Smithsonian Institution)
• Sea Slug Forum
• Nudibranchs
• The Slug Site
• The Cephalopod Page
• CephBase
• Conch News - About the Family Strombidae
• Conchologist's Information Network
• Annelid Resources: Another Can of Worms
• Index to Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates
• Tardigrades
• Tardigrades: Bears of the Moss
• Crustacea.net - An Information Retrieval System for Crustaceans of the World
• Crustacean Biodiversity Survey
• Entomology Index of Internet Resources
• Systematic Entomology Laboratory WWW Homepage (USDA)
• Welcome to the Wonderful World of Insects
• Iowa State Entomology Image Gallery
• North American Butterfly Association
• Northern Prairie Wildlife Research Center (USGS)
  • Butterflies of North America
  • Moths of the United States
  • Dragonflies and Damselflies of the United States
  • Mayflies of the United States
  • Stoneflies of the United States
• The Diptera Site (SEL, USDA)
• Mayfly Central
• Digital Dragonflies
• Odonata Larvae of Michigan
• Orthoptera Species File Online
• Dust Mites - A Primer
• ScaleNet: All about Scale Insects (Coccoidea)
• Beetles (Coleoptera) and Coleopterists
• Tiger Beetles of Connecticut
• FLEAS - Siphonaptera
• University of Florida Book of Insect Records
• The Arachnology Home Page
• Araneae, Spiders of North-West Europe