(a) Numerical taxonomy. Heywood (1967) defined numerical taxanomy as "the numerical similarities between group of organisms and the ordering of these groups into higher ranking taxa on the basis of these similarities. "It employes collection of data, analysis and meaningful synthesis. Characters of organisms are given equal weight and the relationship of the organisms are numerically determined, usually with the aid of a computer.
(b) Chemotaxonomy. The approach of taxanomy in which specific chemicals (micro- and macro-molecules) of organisms are used in classification or as evidences in solving taxonomic probems is called chemotaxonomy. The chemical iformation can be obtained from any part of the plant or animal. The sequencing in DNA and chemical nature of proteins have been utilized to establish similarities and relationships.
