Species must be named for us to be able to talk about them and write about them. If everyone was allowed to name a new species whatever they liked when they liked the whole system would be chaos. Which is exactly what happened in the scientific community before Carolus Linnaeus invented binomial nomenclature in 1758.
This system gives every species two names: a genus and a species name. A Genus is a group of closely related species. This is similar to your first and surname. Your first name e.g. John is your species name and your surname e.g. Smith is the genus you belong to in this example your family.
There are rules about how you spell scientific names as well. The genus is always capitalised and the species name is always lower case. The genus and species names are always written in Italics.
Take human beings for example:
Human beings are Homo (Genus) sapiens (species)
This is the very bottom of the classification system, and the section you will be most familiar with. The whole system goes like this:
Let’s look at the classification for Human beings Homo sapiens, and compare it to that of a Blue Whale
Try it for yourself and complete the classification for a starfish: