In this article we will discuss about:- 1. Definition of Taxonomy 2. Scope of Taxonomy 3. Levels.
Definition of Taxonomy:
The term taxonomy is derived from two Greek words – taxis meaning arrangement, and nomos meaning law. It was first proposed in 1813 by A.P. de Candolle (a professor of Montpellier University in France) in its French form, for the theory of plant classification. “Taxonomy is the theoretical study of classification, including its bases, principles, procedures and rules”. According to Mayr (1982), “Taxonomy is the theory and practice of classifying organisms”.
Taxonomy is thus an information system comprising of classification, nomenclature, descriptions and identification. According to Christoffersen (1995), taxonomy has become the most basic activity in biology, dealing exclusively with the discovery, ordering and communication of patterns of biological taxa. It, however, leans heavily on systematics for its concepts.
Scope of Taxonomy:
The scope of taxonomy and that of systematics in particular are:
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1. It works out a vivid picture of the existing organic diversity of our earth and is the only science that does so.
2. It provides much of the information, making it possible for the reconstruction of the phylogeny of life.
3. It reveals various interesting evolutionary phenomena, making them available for casual study by other branches of biology.
4. Almost entirely, it supplies information needed by the various branches of biology.
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5. It provides names for each kind of organism, so that all concerned can know what they are talking about and such information can be recorded, stored and retrieved when needed.
6. It differentiates the various kinds of organisms and points out their characteristics through descriptions, keys, illustrations etc.
7. It provides classification, which are of great heuristic and explanatory values in most branches of biology like evolutionary biochemistry, immunology, ecology, genetics, ethology, historical geology etc.
8. It is important in the study of economically or medically important organisms.
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9. It makes important conceptual contributions in population thinking, thereby making it accessible to experimental biologists. It thus contributes significantly to the broadening of biology and to a better balance within biological science as a whole.
Levels of Taxonomy:
α (alpha), β (beta) and Ƴ (gamma) taxonomy:
There are three phases of taxonomy symbolized as α (alpha), β (beta) and Ƴ (gamma) taxonomy:
Alpha (α) taxonomy:
Alpha (α) taxonomy is the analytic phase in which the species are identified, characterised and named. At this level when a new species is discovered it is named in accordance with Linnaeus system of binomial nomenclature. Here priority is given to the one who publishes his work first. All problems relating to species are dealt here.
Beta (β) taxonomy:
Beta (β) taxonomy refers to the arrangement of the species into a natural system of hierarchial categories. This is done on the basis of easily observable, shared, structural features and evaluation of numerous characters. Thus, β-taxonomy relates to the search of a natural system of classification. Each taxon would thus possess diagnostic features unique to that taxon.
Gamma (Ƴ) taxonomy:
Finally, gamma (Ƴ) taxonomy designates the analysis of intraspecific variations and evolutionary studies. Much attention is paid to a causal interpretation of organic diversity — study of speciation. But in actual practice it is rather difficult to dissociate them because these overlap and integrate.
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There are only a few groups of animals (some vertebrates, especially the birds and a few insect orders like Lepidoptera etc.) where the taxonomy has reached up to the gamma level. Otherwise, in almost majority of the groups, the Works are still at the alpha and beta level.