Taxonomy is the study of the classification of organisms, according to their differences and similarities. The oldest form of taxonomy is what is now called classical taxonomy and it is concerned primarily with the description, naming, and classification of organisms based on their morphological characteristics. An adaptation of classical taxonomy is now taking into account molecular and biochemical (chemosystematics) data that is now available. Numerical taxonomy uses mathematical principles. This is done to try to remove the subjective nature of taxonomy that can lend more weight to certain characters than others, just because a structure is obvious and apparent it may not have much importance taxonomically or evolutionarily speaking. An example of this approach is cladistics. This looks at how organisms have evolved from a common ancestor and how particular structures have altered with time. Cladistics attempts to recreate the phylogeny of the organisms under study. Cytotaxonomy looks...