Biological classification
The classification  has its root in the work of Aristotle who invented a multi-ranked system. A great influence was Carolus Linnaeus, who popularized the idea of binomial nomenclature using a  two-part name indicating the genus, and the species. The human species is named Homo sapiens. Names of species are often printed in italics, although there is no obligation to do so (this also goes for names of genera, etc., etc.)