<P> Taxonomy (from Ancient Greek τάξις (taxis), meaning' arrangement', and - νομία (- nomia), meaning' method') is the science of defining and naming groups of biological organisms on the basis of shared characteristics . Organisms are grouped together into taxa (singular: taxon) and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a super group of higher rank, thus creating a taxonomic hierarchy . The principal ranks in modern use are kingdom, phylum, class, order, family, genus and species . The Swedish botanist Carl Linnaeus is regarded as the father of taxonomy, as he developed a system known as Linnaean taxonomy for categorization of organisms and binomial nomenclature for naming organisms . </P> <P> With the advent of such fields of study as phylogenetics, cladistics, and systematics, the Linnaean system has progressed to a system of modern biological classification based on the evolutionary relationships between organisms, both living and extinct . </P>

The american system of classifying animals is based on