Alpha diversity (α-diversity) is the biodiversity within a particular area, community or ecosystem, and is measured by counting the number of taxa within the ecosystem (usually species).

The field of ecology includes researchers who study current biodiversity. Biodiversity of the past is the realm of Paleoecology. Past biodiversity is usually viewed by plotting the taxonomic richness of a geographic area over a temporal scale. For example, Sepkoski produced a diagram showing the diversification of skeletonized marine invertebrate taxa. This famous diagram shows a distinct three distinct logistic curves representing the diversification of three distinct faunas.

Other measures of diversity

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Alternative ways to measure biodiversity includes:

• Beta diversity - species diversity between ecosystems; this involves comparing the number of taxa that are unique to each of the ecosystems.
• Gamma diversity - taxonomic diversity of a region with several ecosystems.
• Global diversity - overall biodiversity of Earth.

Recent research

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Jack Sepkoski a University of Chicago palaeontologist studied the fossil record and the diversity of life on Earth. Jack John Sepkoski died in 1999. http://www-news.uchicago.edu/releases/99/990504.sepkoski.shtml

Richard K. Bambach is Professor Emeritus of Paleontology at Harvard University. His research is focused on community paleoecology emphasizing the nature of fossil assemblages, analysis of gradients in the distribution of fossil assemblages reflecting environmental patterns, analysis of ecologic structure of fossil assemblages and changes in apparent community organization through time. http://www.geol.vt.edu/profs/rkb/rkb-r.html

Jonathan M. Adrain is an associate professor at the University of Iowa, studying Silurian trilobite alpha diversity and the end-Ordovician mass extinction. http://www.uiowa.edu/~geology/people/faculty/adrain

Sarda Sahney is a researcher at the University of Bristol in England who is conducting a large-scale macroevolutionary study on tetrapod alpha diversity through the Phanerozoic. http://seis.bris.ac.uk/~glxss/

External links

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An explanation of many specific biodiversity terms using illustrations http://www.uwsp.edu/geo/faculty/heywood/geog358/Diversity/Biodiversity.htm

References

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Sepkoski, J.J. Jr, 1984, A kinetic model of Phanerozoic taxonomic diversity, III. Post Paleozoic families and mass extinctions. Paleobiology 10: 246-267. Whittaker, R.H., 1972. Evolution and measurement of species diversity. Taxon 21: 213-251.

biodiversity