taxonomy(redirected from Classification Theory)
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in biology, the systematic categorization of organisms into a coherent scheme. The original purpose of biological classification, or systematics, was to organize the vast number of known plants and animals into categories that could be named, remembered, and
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The arrangement or classification of objects according to certain criteria. Systematics is a broader term applied to all comparative biology, including taxonomy. For classifying plants and animals, where the term taxonomy is most often applied, the criteria are characters of structure and function.
A given character usually has two or more states. These variations are used as the basis of biological classification, grouping together like species (in which the majority of the character states are alike) and separating unlike species (in which many of the character states are different). Since the acceptance by biologists of the concept of organic evolution, more and more effort has been made to produce systems of classification that conform to phylogenetic (that is, evolutionary) relationships. Taxonomy is thus concerned with classification, but ultimately classification itself depends upon phylogeny—the amount, direction, and sequence of genetic changes. Scientists try to classify lines, or clusters of lines, of descent. This has not always been the case, and in the past various other criteria have been used, such as whether organisms were edible (ancient times) and whether flowers had five stamens or four or some other number (Linnaean times). Modern taxonomists generally agree that the patterns or clusters of diversity they observe in nature, such as the groups of primates, the rodents, and the bats, are the objective results of purely biological processes acting at different times and places in the past. At the least, animal and plant taxonomy provides a method of communication, a system of naming; at the most, taxonomy provides a framework for the embodiment of all comparative biological knowledge. See Animal systematics, Classification, biological, Numerical taxonomy, Organic evolution, Phylogeny, Plant taxonomy
taxonomybetween forms of taxation is between progressive forms (those proportional to income or wealth, e.g. income tax) and regressive forms (those levied at a flat rate, e.g. a poll tax). Historically, struggles by governments to increase state revenues, especially to fund WARFARE, were a major factor in state formation. As well as raising revenue, modern governments have also used changes in taxation (‘fiscal policy’) as an instrument of control over the economy or to inhibit undesirable social activities (e.g. smoking). In modern times, taxation has been frequently used as a main means of redistribution of income and wealth. However, the extent to which redistribution actually occurs as the result of taxation is debated. In the UK, for example, it is clear that some elements of redistribution through taxation benefit the better-off more than they do poorer sections of the community (e.g. tax relief on mortgages, or educational grants). Overall, even with redistribution, the poor pay a greater proportion of their incomes in taxes than other social groups. See also FISCAL CRISIS IN THE CAPITALIST STATE, STATE EXPENDITURES.
taxonomythe theory and practice of CLASSIFICATION. As a scientific procedure taxonomy has been especially prominent in biology (e.g. hierarchical formal classificatory systems such as that of Linnaeus). Some proposed classifications of societies in sociology have used such classificatory systems as models (e.g. the work of Herbert SPENCER and W. G. RUNCIMAN). Although argument has raged in biology and elsewhere as to whether taxonomies should be seen as ‘natural’ or ‘imposed’, the only answer that can be given is that taxonomies are theory-relative, that when theories change taxonomies will also change, as in the move from pre- to post-Darwinian biology
the theory of the classification and systematization of complexly organized spheres of reality, which usually have a hierarchical structure, such as the organic world or the subjects studied in geography, geology, linguistics, or ethnography. The concept of taxonomy first arose in biology; the term itself was first proposed in 1813 by the Swiss botanist A. P. de Candolle, who developed a classification of plants.
For a long time, the term “taxonomy” was usually used in biology as a synonym for “systematics.” In the 1960’s and 1970’s, there arose a tendency to define biological systematics more broadly as the science of the diversity of living organisms and of the kinship relationships between them; taxonomy was defined as a narrower discipline, or a division of systematics, concerned with the principles, methods, and rules of the classification of organisms. This point of view is advocated by the American taxon-omists G. G. Simpson and E. Mayr and the Soviet botanist A. L. Takhtadzhian. Thus, systematics deals with actual groups of organisms (taxons), and biological taxonomy is concerned primarily with the creation of a science of taxonomic categories and of the system of such categories, which would permit construction of a more informative, less contradictory, and more convenient classification with a maximum correspondence to the natural system of organisms.
The system of the organic world is exceptionally complex in structure, and serious difficulties are encountered in constructing a theory of the system; for example, in many cases there are no clear boundaries between taxa, and, consequently, it is necessary to operate with very large numbers of characters and properties. This complexity and the resultant difficulties have stimulated numerous attempts to give a theoretical (in some instances, a formal) substantiation of taxonomy and the basic taxonomic categories (numerical taxonomy). These attempts have made it possible to apply modern mathematical methods to taxonomy, but they have not yet led to generally accepted fundamental results.
In the second half of the 20th century, problems in taxonomy have come to play a significant role in biology and many other sciences that deal with large numbers of hierarchically organized discrete objects. This reflects a general tendency in modern science to assign greater importance to typology in scientific thought. Furthermore, not just the natural differences between given groupings of taxonomic categories, but even the fundamental concepts and goals of taxonomy are interpreted differently in different fields of knowledge. In linguistics, for example, taxonomy rests on the delineation of linguistic units in a text and the study of the units’ properties through analysis of their order and distribution. Accordingly, linguistic taxonomy operates by means of categories of a class of elements and of the type of relationship between the elements and classes. In linguistics, taxonomy is sometimes interpreted as the grouping of similar grammatical categories found in various languages into a single, systematized category, such as the passive voice or perfective aspect. Thus, the general principles of taxonomy as a theoretical discipline are still in the process of being established.
REFERENCESMayr, E. Printsipy zoologicheskoi sistematiki. Moscow, 1971. (Translated from English.)
Liubishchev, A. A. “Okriteriiakh real’nosti v taksonomii.” In Informatsionnye voprosy semiotiki, lingvistiki i avtomaticheskogoperevoda, fasc. 1. Moscow, 1971.