When writing the scientific names for organisms, which are written in Latin, the name for the organism must contain two parts. The first part, genus name, is written in italics and is capitalized. The second part, epithet, or a specific description of the species, is italicized, but not capitalized.
The system for scientific nomenclature for plants and animals started developing in the 18th century. The idea, and the first few thousand scientific names, belong to Swedish scientist Carolus Linnaeus. In his honor, many species' scientific names, including Homo sapiens, include Linnaeus or L. as the third part of their name. This third part of the scientific name for a species is called "describing author" and is added after a particular individual has scientifically described the organism in a refereed journal.
Scientific names for species are written in Latin, a dead language, to ensure that these names stay the same over long periods of time and across language barriers. Scientific naming of species is closely connected to the study of how organisms evolved and how they are related to each other. For instance, the only surviving human species now is called Homo sapiens, whereas in prehistory other species of the genus Homo existed: Homo habilis and Homo erectus. Scientific names for species sometimes change, as new discoveries are made. For example, what had been considered one species turns out to be two, and vice versa.