The naming and organizing of the millions of species of plants and animals is frequently called taxonomy; such classifications provide a basis for comparisons and generalizations. Carolus Linnaeus composed a classification system for two major groups: plants (1753) and animals (1758). He categorized the organisms by perceived physical differences and similarities. Every plant and animal was given two scientific names (binomial method) in Latin, one for the species and the other for the group or genus within the species. This system of nomenclature (naming) continues to be used today. Examples of binomical nomenclature include: Schistocerca americana (grasshopper) and Pinus strobus (white pine).