|Binomial classification is in its simplest
form is a way of naming the species by means of a two
names, both Latin. It was first introduced by Carolus
Linnaeus, a Swedish botanist and physician, who's
work in the 18th century still stands as the
basis of the modern day classification systems.
In Binomial classification the first name, which begins with a capital letter is known as the Genus. The genus is a group of species more closely related to one another than any other group of species. The second part of the binomial represents the species itself and is always printed with all letters in lower case.
As an example, in the cat family, the genus Panthera is coupled with the species leo to form Panthera leo, the Lion. Likewise, Panthera is coupled with tigris, to form Panthera tigris the Tiger. In simplified terms both the Lion and Tiger share common traits, for example they both roar and as such share a common genus - Panthera, whilst clearly remaining separate species.
Because some species can be split in to further subspecies, it is common for a third name to be used this is known as the trinomial. Using the example above, persica can be added to Panthera leo to name the Asiatic lion and is written in full as Panthera leo persica.
In discussing differing form within a species it is common for the trinomial to be abbreviated by use of single letters and full stop. Using the Asiatic lion as an example, it could be written as P.l. persica, the Panthera leo being abbreviated.