Classification of Organisms

Classification of Organisms To communicate with each other about the diversity of life, biologists have found it necessary to name and classify things

Taxonomy is the science of classifying living things. • The Greek philosopher and biologist Aristotle was the first to attempt the classification of organisms based on their structural differences

Following the Dark Ages in Europe, the English naturalist John Ray, introduced a more complete classification system that included the concept of species. Species are groups of interbreeding natural populations that are reproductively isolated from other groups.

In the 18th Century, Carolus Linnaeus developed our modern hierarchial system of classification. • The major catagories or TAXA are:

Kingdom • Phylum • Class • Order • Family • Genus • Species

These can be subdivided into finer catagories such as superclass, subclass, infraclass, superorder, suborder. • Linnaeus’ system for naming species is known as BINOMIAL NOMENCLATURE (a two name naming system)

Each species has a name composed of two words. The first is the genus and the second is the species. These names come from Latin or Greek • The GENUS is written with a capital letter and is always a noun. • The SPECIES is written with a small letter and is usually an adjective

To show that these names are scientific names they are either underlined or written in italics. • For example, Homo sapiens.

Classification of Organisms