Taxonomy is the science of naming and classifying organisms. Carolus Linnaeus developed the system of taxonomy that is still widely used today, called the Linnaean System.  

The Linnaean System classifies organisms based on their physical and structural similarities, using a hierarchy. This system uses binomial nomenclature (a two-part naming system). The first part of the name is the genus and the second part is the species

Go to the Science Prof Online site, and read the two pages on Biological Classification & Binomial NomenclatureYou will need to know the material on the two pages for upcoming assignments. 

Species and genus are closely related. When writing a name genus is always capitalized and species is always lowercase, and always follows the genus name, it is never written alone. An example of a genus and species is Falco peregrinus, Peregrine Falcon. 

Each level as you move from specific (species) to broader (domain) is included in the level above it.