What are the two words in a scientific name?

The first is the genus, this is always capitalised. The second Word is the species name, which is never capitalised. Both Words are always written in italics or underlined if handwritten. For example, the species name for humans is Homo sapiens; Homo is the genus name, and sapiens is the species name. Sometimes, a scientific name will contain an additional Word at the end, in zoology this will indicate a sub-species; in botany additional terms may refer to sub-species, varieties, hybrid varieties etc.