Skip Navigation


Living organisms are divided into an hierarchical system of classification. For instance, the Animal Kingdom is divided into several phyla (sing. phylum). Each phylum is further divided into classes, one of which is Insecta.

Classes are further divided into orders, families, genera (sing. genus) and finally species.

Each recognised species of organism is known by a scientific name which consists of two parts - its genus name and its species name. So the common house fly is called Musca domestica. This is known as binomial nomenclature. This name is always shown in italics or alternatively is underlined.

Common names do not have scientific validity. Some organisms have no common name - others have several.

Copyright © University of Sydney. Last updated February, 2004. Site construction and maintenance: eResources Unit. Email us here with your comments and feedback.