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classification/clas·si·fi·ca·tion/ (klas″ĭ-fĭ-ka´shun) the systematic arrangement of similar entities on the basis of certain differing characteristics.
classificationAny systematic arrangement of similar entities organisms, disease processes, etc, which are separated based on specific types of differences. See Ambulatory payment classification, Ann Arbor classification, Bethesda classification, Black's classification, BLEED classification, Bormann's classification, Broders' classification, Caldwell-Molloy classification, Cambridge classification, Canadian Cardiovascular Society functional classification, Cladistic classification, Deafness classification, DeBakey classification, Denis classification, Dukes classification, FAB–French-American-British classification, FDA classification of devices, FDA Classification of Teratogenicity, Gustilo classification, Hamilton classification, Hazard classification, Hinchey grading classification, International Classification of Diseases–9th edition, Clinical Modification classification, International Workshop classification for chronic lymphocytic leukemia, ILO classification, Kiel classification, Killip classification, Lovejoy's classification, Ludwig classification, Lukes-Collins classification, Marseille classification, McKusick classification, New York Heart Association classification, Norwood classification, Obesity Task Force classification, Papanicolaou classification, Pesaro classification, Physical status classification, Quebec classification, Rappaport classification, REAL classification, Rosenthal classification, Savary-Miller classification, Shandall classification, TNM classification, Ulcerative colitis classification, Vaughan Williams classification, WHO classification, Wolfe classification, Working Formulation.
classificationthe ordering of organisms into groups on the basis of their relationships. The groups are referred to as TAXA, for example, kingdom, phylum, division, class, order, family, genus, species. Natural classification based on overall evolutionary (phylogenetic) relationships is the usual form, but artificial classification based on nonevolutionary considerations or on one or a few characters is often used in identification. The CLADISTICS approach has gained favour in some circles.
Classification is not to be confused with ‘identification’ which is the placing of individuals by deductive procedures into previously established groups. Most criteria used in classification have been structural, but as more becomes known of genetical structures and sequences, these are increasingly used as a basis for classification. Several workers have suggested new classifications based on DOMAINS, and that suggested by Woese (1994) is shown in comparison with the widely recognized classical approach (the ‘five kingdom system’) of Whittaker (1969). See fig. 106 . At present the classification of organisms is in a state of flux. In the modern classification of Woese, each domain contains groupings of kingdom-equivalent status so that many other groupings may attain similar status to animals and plants, reflecting the diversity of microorganisms and their evolutionary importance. This can be seen more clearly in the phylogenetic tree in Fig. 107 (after Woese 1994) where the groupings in the domain Bacteria are merely representative of a larger number.
For viruses, classification is normally based on type of nucleic acid, morphology, presence or absence of an envelope and replication properties. A number of families is recognized, with the family name ending in -viridae, e.g. Poxviridae (double-stranded DNA, enveloped animal viruses). The viral genus has the suffix -virus, e.g. Orthopoxvirus, and the viral species is given a common descriptive name ending with virus, e.g. smallpox virus. In general, higher taxa e.g. order, kingdom, have not yet been assigned, but viruses are usually separated into large groups based on host preference e.g. animal viruses, plant viruses and bacterial viruses (see BACTERIOPHAGES).
Patient discussion about classification
Q. How are Heart Murmurs Classified? What are the characteristics of different heart murmurs?
Notice that the murmur begin with the heart sound and lasts all through the beat.