Biodiversity refers to the variety of life. It is seen in the number of species in an ecosystem or on the entire Earth. Biodiversity gets used as a measure of the health of biological systems, and to see whether there is a danger that too many species become extinct. The United Nations designated 2011–2020 as the "United Nations Decade on Biodiversity".
The term biodiversity first appeared in a publication in 1988 when entomologist E. O. Wilson used it as a title. Since then, the term has often been used by biologists, environmentalists, political leaders, and citizens. A similar term in the United States is "natural heritage." It predates the others and is more accepted by the wider audience interested in conservation. Broader than biodiversity, it includes geology and landforms.
Biologists most often define biodiversity as the "totality of genes, species, and ecosystems of a region". An advantage of this definition is that it seems to describe most circumstances. There are three levels at which biological variety can been identified:
- species diversity
- ecosystem diversity
- genetic diversity.
The idea can be used for tackling practical problems in conservation, for example:
- Dasmann R.F. 1968. A different kind of country. MacMillan, New York. ISBN 0-02-072810-7
- Soulé M.E. and B. A. Wilcox. 1980. Conservation biology: an evolutionary-ecological perspective. Sinauer. Sunderland, Massachusetts.
- Edward O.Wilson, editor, Frances M.Peter, associate editor 1988. Biodiversity, National Academies Press. ISBN 0-309-03783-2; ISBN 0-309-03739-5 online edition
- Global Biodiversity Assessment. UNEP, 1995, Annex 6, Glossary. ISBN 0-521-56481-6, used as source by "Biodiversity", Glossary of terms related to the CBD, Belgian Clearing-House Mechanism. Retrieved 2006-04-26.
- Tor-Björn Larsson (2001). Biodiversity evaluation tools for European forests. Wiley-Blackwell. p. 178. ISBN 978-87-16-16434-6. Retrieved 28 June 2011.