a, whilst clearlyremaining separate species. To allow further subdivision, the prefixes sub-and super- may be added to any category. In addition, special intermediatecategories-such as branch (between kingdom and phylum), cohort (betweenclass and order), and tribe (between family and genus)-may be used incomplex classifications. Closely related species are a genus, closelyrelated genera (plural form of genus) are grouped together in a family.Closely related families are grouped into an order, and so on, into moreinclusive categories, or levels in the classification hierarchy. TaxonomicHierarchy Approximately one and a half million species have beenclassified and there are estimates that over five million species remain tobe discovered. For biologists to order this mass of information, ascientific system called taxonomy was introduced. The basic idea is togroup species with similar characteristics together into families, and togroup the families together into broader groupings. To this end, thetaxonomic categories where devised, and they create the taxonomic hierarchy.The hierarchy goes (with an example):*Categories Example Kingdom Animalia Phylum (Plural = Phyla) Cordata*In plants, this category is often called a division*Class Mammalia Order Carnivora Family Canidae Genus Canis Species Lupus (the Wolf)Every species is in only one genus. Similarly, every genus is in only onefamily, and so forth up the hierarchy. The most inclusive category forclassifying groups of similar organisms is the Kingdom. It is arguedexactly how many Kingdoms there are though. Up until recently, only twokingdoms were generally used, the plant and animal kingdoms. Now howeverthere are 5 established kingdoms and one controversial unofficial kingdom.The 5 kingdoms: 1. Kingdom Animalia (The Animal Kingdom) ex: Multi-cellu...
