Q. Classify the diversity of organism in different groups

• The goal of taxonomy is to develop a workable classification that reflects evolutionary relationships and provides identification and nomenclature.

• Species represent lineages produced by evolution and branching genetic relationship exists among the taxa of each group.

• Categories such as species, genera, families and orders are not rigid but are flexible and individually delimited for each group. Hierarchy is established by International Code of Botanical Nomenclature for plants and International Code of Zoological Nomenclature for animals.

• Taxa are based on the correlation of characters and discontinuities in the variation pattern. Any attribute of the plant animal may be selected as character and they do not have fixed value at all ranks.

• The selected character should be constant and must show little environmental variation for delimiting taxa.

• Taxa should be monophyletic. Taxonomic treatments should be practical and consistent in their use of the various categories.

• Taxa may resemble one another because of either convergence or parallelism.

• In the development of classification whenever possible, taxa should be sampled throughout their range and all taxa at lower ranks should be examined.

• Ancestral features and trends of diveFsity may often be recognised in the structure of living organisms.

• Ancestral organisms should be given careful consideration.

• Evolution may result in reduction or loss of parts which should also be taken into consideration.

• Morphological characters should be given proper importance because they provide guidance to primitive versus advanced features and aid in developing phylogenetic relationships. Thinking should be very flexible so that modifications in classification may be made as soon as new evidence is available.

• In phenetic taxonomy, taxa are organised and classified on the bases of similarities of the phenotypes of the organism.

• The modern taxonomy includes cladistic taxonomy which involves summarising knowledge about similarities among taxa in terms of a branching diagram called a cladogram depicting the hypothetical evolutionary histories of the organisms.

• Biogeography is also an important part of taxonomy because it analyses the pattern of distribution of organisms and relates these to the systematic of the organisms. Classification thus enables us to summarise our knowledge about the organisms, and that is one of the most important functions of taxonomy. The saving of time and effort is thus one way in which we can define the utility and purpose of classification.