Linnaeus classified organisms into two kingdoms, plants and animals. This division goes back to the ancient Greeks. Linnaeus also grouped minerals as a third kingdom.
Carolus Linnaeus (Carl von Linné) devised the first modern system for classifying living organisms, known as taxonomy. Classifying organisms makes it easier for scientists to study similarities and differences, and to place newly discovered organisms into the correct categories. Linnaeus is responsible for the further, organized divisions grouping organisms within a kingdom so that more general groups of like organisms could be subdivided. His classification divided kingdoms into class, order, genus and species. Scientists have since added additional levels of classification such as phylum and family. There are currently six kingdoms; we no longer include minerals in this system. Linnaeus is also responsible for using the genus and species of an organism as universal scientific names; this system is called binomial nomenclature.