Why Do Scientific Names Have Two Parts?

Biology uses a convention known as binomial nomenclature to uniquely name the diverse organisms of our planet. The two parts of a scientific name are the genus, which is capitalized, and the species, which is not; both names are italicized. Let’s look at the scientific name for the common peach, Prunus persica. Prunus indicates the genus, which, in this case, includes other familiar fruit trees, such as the cherry, plum, almond, and apricot. All these trees are very closely related, so all have Prunus in their binomial names. The species name persica distinguishes the peach from other members of the genus, such as the apricot, which is Prunus armeniaca, and the almond, which is Prunus dulcis.

Some scientific names have three parts: the genus, the species, and a subspecies. For example, the domestic dog is called Canis lupus familiaris. Here the subspecies, familiaris, indicates that the dog is directly descended (through domestication) from the gray wolf, Canis lupus.