A: The second part of an organism's scientific name is its species. The system of naming species is called binomial nomenclature. The first name is the genus, and the second name is the species. In binomial nomenclature, species is the most specific designation. This system enables the same name to be used globally so that scientists can communicate with one another. Genus and species are just two of the categories in biological classification, otherwise known as taxonomy. The levels of classification, from most general to most specific, are kingdom, phylum, class, order, family, genus, and species. As shown, binomial nomenclature includes only the two most specific categories.