Carl Linnaeus, a Swedish botanist, created the modern system of scientific classification. This system names and classifies organisms according to their similarities and their differences.
This system places living things into seven groups (also known as taxons), as follows:
In this scheme, living things are organized from the most general to the most specific. Therefore, you can see that each species, belongs to a genus, each genus belongs to a family, each family belongs to an order, and so on.
Kingdoms are the largest groups, with millions of different kinds of organisms in each Kingdom. Species are the smallest groups. Each species is made up of individuals of the same type (for example, plants or animals) who are capable of breeding and producing fertile offspring of the same type.
For example, both lions and tigers are in the Genus Panthera. While any two lions are in the same species, as are any two tigers, lions and tigers are in different species since they can't interbreed and produce fertile offspring of the same type. The result of a mating between lion and tiger would be neither a lion nor a tiger but, perhaps, a "Liger"! A lion is known as a Panthera leo and a tiger is known as Panthera tigris. The first name is the genus and the second name is the species.
Binomial nomenclature is the system of naming species of living organisms. The basis of this system is that each species name has two parts - the genus name and the species name. While this two-part name is often called a "Latin name," the preferred terminology is "scientific name." This is because the words used to create these names are no longer necessarily from Latin. They are sometimes words from other languages or proper names that are "Latinized", or made to appear as Latin, for naming purposes.
In scientific naming, the first letter of the first name (the genus) is always capitalized, while the second name is not capitalized. An example of a scientific species name is Homo sapiens, the name for the human species. Humans belong to the genus Homo - meaning "the same" or "the same as me," which refers to humans, with the specific name of "sapiens" - which means wise. Wise Human. Our pride for our species certainly shows through in its name!
The naming convention also calls for italics to be used for the names of the genera (plural of genus) and lower taxa, such as species. If the binomial name is hand-printed, each word should be underlined. Family names and higher (up through Kingdom), are to be printed or typed in plain text (not italicized or underlined).
In many cases, species is divided further into subspecies. This results in a trinomial (three-part) name rather than a binominal name.
Another factor used in the naming of species is the use of the authority and date of the species. For example, the name given to a particular type of flower fly species is "Eristalis gatesi Thompson, 1997." The genus is Eristalis and the species is gatesi. The name "Thompson" tells us who originally described the Species, and the date - 1997 - is the date of the publication in which the original description can be found.
After 1930, scientific authorities declared that any new names must come with a description (or reference to one) telling what the name means. An example of this would be:
Microchilo murilloi Bleszynski, 1966 (crambid moth)
- Genus = Microchilo
- Species = murilloi
- Authority = Bleszynski
- Date = 1966
- Description = crambid moth
Why Use Binomial Nomenclature?
The invention and use of binomial nomenclature is of great value to the scientific community because it provides clarity. By using a standard method of scientific naming, we avoid the confusion that can come about when trying to use common names. An organism may have more than one common name and these common names can vary from country to country, or even between different parts of a country. Two examples of this would be:
Felis concolor - the scientific name for the animal known as mountain lion, cougar and puma. These are all the same animal, but are commonly known by various names depending upon the part of the United States in which you live.
Armadillium vulgare - the scientific name for a small crustacean that rolls into a ball when disturbed. You many know it as a roly-poly, a sowbug, a sow's ear, or a pillbug. Again, these are all the same creature!
As you can see, many organisms may have more than one common name, but will always have only one scientific name. Scientific names can be used all over the world and in all languages and be understood by all.