Biosphere
- Biosphere, as per Wikipedia
- The Biosphere
- Encarta's page on the ecosystem
- Food chains and webs
- Trophic levels, by the geography portal
- Encarta's page on Food web
- The flow of energy in ecosystems
- Biodiversity, by Eco Online
- Why biodiversity is important, by the David Suzuki Foundation
- What is Biodiversity and why is it important?
