Taxonomic Hierarchy

Carolus Linnaeus introduced the taxonomic hierarchy - the arrangement of taxonomic ranks in descending order, from the broadest (Kingdom) down to the narrowest (Species).

Species is the lowest rank and shows the highest similarity among its members - e.g. Helianthus annuus and Helianthus tuberosus are both herbs, but differ in that the latter is perennial. Genus groups multiple species that share characters distinguishing them from the species of another genus (e.g. Helianthus, Tridax). Family groups several genera that share some similarity (e.g. Asteraceae). Order groups families sharing fewer similarities, and Class groups orders sharing still fewer. Division (equivalent to Phylum) is the next level up, grouping a number of classes (e.g. Magnoliophyta). Kingdom sits at the very top (e.g. Plantae). …