Alpha diversity

Alpha diversity (α-diversity) is the biodiversity within a particular area, community or ecosystem, and is measured by counting the number of taxa (distinct groups of organisms) within the ecosystem (eg. families, genera, 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 three distinct logistic curves representing the diversification of three distinct faunas.

Other measures of diversity

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

Jack Sepkoski a University of Chicago palaeontologist studied the fossil record and the diversity of life on Earth. Jack John Sepkoski died in 1999. [1]

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. [2]

Jonathan M. Adrain is an associate professor at the University of Iowa, studying Silurian trilobite alpha diversity and the end-Ordovician mass extinction. [3]

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. [4]

External links

An explanation of many specific biodiversity terms using illustrations [5]


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 is the variation of life forms within a given ecosystem, biome or for the entire Earth. Biodiversity is often used as a measure of the health of biological systems.
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A community is a social group of organisms sharing an environment, normally with shared interests. In human communities, intent, belief, resources, preferences, needs, risks and a number of other conditions may be present and common, affecting the identity of the participants and
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ecosystem is a natural unit consisting of all plants, animals and micro-organisms in an area functioning together with all the non-living physical factors of the environment.
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A taxon (plural taxa), or taxonomic unit, is a name designating an organism or group of organisms. A taxon is assigned a rank and can be placed at a particular level in a systematic hierarchy reflecting evolutionary
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Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. Scientific classification also can be called scientific taxonomy, but should be distinguished from folk taxonomy, which lacks scientific basis.
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Genera was an operating system and development environment for Lisp machines developed by Symbolics. It was essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI. The ~1.
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species is one of the basic units of biological classification. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring.
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Ecology (also known as Oekologie, Okology, or Oekology[1],from Greek: οίκος, oikos, "household"; and λόγος, logos
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Paleoecology uses data from fossils and subfossils to reconstruct the ecosystems of the past. It includes the study of fossil organisms and their bromalites and other trace fossils in terms of their life cycle, their living interactions, their natural environment, their manner of
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Beta diversity (β-diversity) is a measure of biodiversity which works by comparing the species diversity between ecosystems or along environmental gradients. This involves comparing the number of taxa that are unique to each of the ecosystems.
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Gamma diversity (γ-diversity) is a measure of biodiversity. It refers to the total biodiversity over a large area or region.

See also

  • Diversity index
  • Alpha diversity
  • Beta diversity
  • Global diversity

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J. John Sepkoski Jr., (July 26, 1948 - May 1, 1999), was a University of Chicago paleontologist. Sepkoski studied the fossil record and the diversity of life on Earth. Sepkoski and David Raup contributed to the knowledge of extinction events.
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