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Species richness [2] is the number of species present in a given area. Species diversity [3] is the relationship between species evenness and species richness. There are many ways to measure biodiversity within a given ecosystem. However, the two most popular are Shannon-Weaver diversity index, [4] commonly referred to as Shannon diversity ...
Biologists most often define biodiversity as the "totality of genes, species and ecosystems of a region". [8] [9] An advantage of this definition is that it presents a unified view of the traditional types of biological variety previously identified: taxonomic diversity (usually measured at the species diversity level) [10]
Species diversity is the number of different species that are represented in a given community (a dataset). The effective number of species refers to the number of equally abundant species needed to obtain the same mean proportional species abundance as that observed in the dataset of interest (where all species may not be equally abundant).
In other related studies, around 1.9 million extant species are believed to have been described currently, [9] but some scientists believe 20% are synonyms, reducing the total valid described species to 1.5 million. In 2013, a study published in Science estimated there to be 5 ± 3 million extant species on Earth although that is disputed. [10]
Then gamma diversity is the total species diversity in the dataset and alpha diversity the mean species diversity per subunit. Beta diversity quantifies how many subunits there would be if the total species diversity of the dataset and the mean species diversity per subunit remained the same, but the subunits shared no species. [2] [7]
Species evenness is combined with species richness, (the number of species in the community), in order to determine species diversity, which is an important measure of community structure. Community structure in turn provides the quantitative basis needed to create hypotheses and experiments that help to increase understanding of how ...
The species-area relationship equation is: =. [10] An example of what a species-area relationship may look like when graphed. In this equation, represents the measure of diversity of a species (for example, the number of species) and is a constant representing the y-intercept.
The scientific work of deciding how to define species has been called microtaxonomy. [ 26 ] [ 27 ] [ 20 ] By extension, macrotaxonomy is the study of groups at the higher taxonomic ranks subgenus and above, [ 20 ] or simply in clades that include more than one taxon considered a species, expressed in terms of phylogenetic nomenclature .