In the eighteenth centruy, a Swedish botanist, Carolus Linnaeus, created a classification system based on similarities and differences among organisms that separate them into categories. Linnaeus prepared the scientific names of each organism in Latin. Even today, we use Latin or Greek to describe organisms so that taxonomists world-wide can communicate. Linnaeus used two words to name each organism, a genus name and a species name. In his system, called binomial nomenclature or two-word naming, the genus describes the group to which the organism belongs, and the species describes the specific animal.
Species vary in a world abounding with an array of life forms.
Imagine a world filled with just one species. Diversification ensures a species-rich world. Organisms have been divided into a five-kingdom classification system. As scientists discovered new organisms and changed their ideas about what characteristics are important in classifying organisms, the classification system changed. This five-kingdom classification system was suggested by R.H. Whittaker in 1969.