Smithsonian Institution
National Museum of Natural History: Ocean Planet: Biological Roulette: Alien Species
Click on the roulette wheel and see how some alien species were introduced into the United States and the effect they have had on our country. This is part of an archived Smithsonian exhibit.
Other
Nature Serve: A Network Connecting Science With Conservation
A network of information about rare and endangered species and threatened ecosystems. The goal is to provide the scientific basis for conservation action. Also includes an online database of information on the plants, animals, and...