Binomial Nomenclature

Binomial nomenclature is the method for naming living things in a scientific context. For example, a small bird with a red breast is commonly called “a robin.” However, the “robin” in Europe is a completely different bird from the “robin” in North America. So scientists use scientific names to distinguish between the two and to indicate the real relatives of those birds. The European robin is Erithacus rubecula whereas the American robin is Turdus migratorius. The genus of the European robin is Erithacus, placing it in the same family as the Old World flycatchers. The second word in a binomial nomenclature, in this case rubecula, is the specific epithet, indicating what species it is. The American robin has the genus Turdus, as a member of the thrush family.

Some people like to call these little amphibians with the sticky toes tree frogs, while others, particularly in Europe, call them tree toads. In actuality, it doesn't matter what common name you like to use (I prefer "treefrog")--this is Hyla versicolor. All true treefrogs are in the genus Hyla.

True toads (not "tree toads") belong to the genus Bufo. This one is an American toad, Bufo americanus.

In case you were wondering, all those "typical" looking frogs, with the webbing between their toes that live around the edges of ponds and lakes most often belong to the genus Rana. This one is a wood frog, Rana sylvatica. So, rather than messing around with vague words like "frog" and "toad" and then trying to figure out which ones are the "true frogs," scientists can simply say Rana, Bufo, or Hyla, and everyone knows what their talking about.

All living things are given a specific epithet in order to distinguish them from other species. The exact characteristics that qualify a species is debated but, usually, a given species must be able to bread regularly with other members of its species in a natural setting. So although the fieldfare (Turdus pilaris) has the same genus as an American robin, it does not breed with T. migratorius in the wild and is thus a different species.

The same can be said of dinosaurs. Many people are not aware that when they call a dinosaur Tyrannosaurus, Stegosaurus, Velociraptor, or Triceratops they are referring to the genus of that dinosaur. Tyrannosaurus rex, short formed as T. rex, defines the species. Of course determining the species of an extinct animal is not directly observable so general differences in the skeleton are studied to determine whether or not the animals should be considered a distinct species.