Q. Phylogenetic species concept ?
Taxonomists (scientists who compare, classify and name organisms) tend to describe a species by studying their physical characteristics and behaviour, and also their genetic and chemical similarities and divergences as a result of evolution. Based on this concept Cracraft proposed the Phylogenetic Species Concept (PSC) in 1983. Here he defines a species as "the smallest diagnostic cluster of individual organisms within which there is parental pattern of ancestry and decent." However, it can be argued that a population, subspecies, stage or a morph can then be elevated to species status. Consequently the number of species recognised becomes highly dependant on the analytical tools used. Even so, the PSC is considered as the most valuable tool for working taxonomists.