Taxonomy (biology)

 In biology, taxonomy is the scientific study of naming, defining and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa, and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a more inclusive group of higher rank, thus creating a taxonomic hierarchy. The principal ranks in modern use are domain, kingdom, phylum, class, order, family, genus, and species. The Swedish botanist Carl Linnaeus is regarded as the founder of the current system of taxonomy, having developed a ranked system known as Linnaean taxonomy for categorizing organisms.

With advances in the theory, data and analytical technology of biological systematics, the Linnaean system has transformed into a system of modern biological classification intended to reflect the evolutionary relationships among organisms, both living and extinct.

Definition-The exact definition of taxonomy varies from source to source, but the core of the discipline remains: the conception, naming, and classification of groups of organisms. As points of reference, recent definitions of taxonomy are presented below:

Theory and practice of grouping individuals into species, arranging species into larger groups, and giving those groups names, thus producing a classification. A field of science that encompasses description, identification, nomenclature, and classification The science of classification, in biology the arrangement of organisms into a classification "The science of classification as applied to living organisms, including the study of means of formation of species, etc." "The analysis of an organism's characteristics for the purpose of classification" "Systematics studies phylogeny to provide a pattern that can be translated into the classification and names of the more inclusive field of taxonomy" 

The varied definitions either place taxonomy as a sub-area of systematics, invert that relationship, or appear to consider the two terms synonymous. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, or a part of systematics outside taxonomy. For example, definition 6 is paired with the following definition of systematics that places nomenclature outside taxonomy

Systematics: "The study of the identification, taxonomy, and nomenclature of organisms, including the classification of living things with regard to their natural relationships and the study of variation and the evolution of taxa". In 1970, Michener et al. defined "systematic biology" and "taxonomy" in relation to one another as follows

This is a field with a long history that in recent years has experienced a notable renaissance, principally with respect to theoretical content. Part of the theoretical material has to do with evolutionary areas, the rest relates especially to the problem of classification. Taxonomy is that part of Systematics concerned with topics to above.

A whole set of terms including taxonomy, systematic biology, systematics, scientific classification, biological classification, and phylogenetics have at times had overlapping meanings – sometimes the same, sometimes slightly different, but always related and intersecting. The broadest meaning of "taxonomy" is used here. The term itself was introduced in 1813 by de Candolle, in his Théorie élémentaire de la botanique. John Lindley provided an early definition of systematics in 1830, although he wrote of "systematic botany" rather than using the term "systematics". Europeans tend to use the terms "systematics" and "biosystematics" for the study of biodiversity as a whole, whereas North Americans tend to use "taxonomy" more frequently. However, taxonomy, and in particular alpha taxonomy, is more specifically the identification, description, and naming of organisms, while "classification" focuses on placing organisms within hierarchical groups that show their relationships to other organisms.