Scientific Classification is the method by which biologists group and categorize species of organisms. All species of life are classified in a ranked hierarchy, starting with Domains, which are then divided into Kingdoms. Kingdoms are divided into Phyla (singular: phylum), which are further divided into Classes, and they, in turn, into Orders, Families, Genera (singular: genus), and Species. The ranks below species are, in zoology, Subspecies and Morph, and in botany, Variety (varietas) and Form (forma).
With advances in knowledge and the discovery of more varied species, the ranks have been further subdivided to allow the precise classification of the relationships of similar species to each other.
Modern scientific classification is based largely on the work of 18th century Swedish biologist Carl Linnaeus.