Binomial Nomenclature

Linnaeus's taxonomy system has two main features that contribute to its ease of use in naming and grouping organisms. The first is the use of binomial nomenclature. This means that an organism's scientific name is comprised of a combination of two terms. These terms are the genus name and the species or epithet. Both of these terms are italicized and the genus name is also capitalized.

For example, the scientific name for humans is Homo sapiens. The genus name is Homo and the species is sapiens. These terms are unique and no other species can have this same name.

Classification Categories

The second feature of Linnaeus's taxonomy system that simplifies organism classification is the ordering of species into broad categories. There are seven major categories: Kingdom, Phylum, Class, Order, Family, Genus, and Species.

A good aid for remembering these categories is the mnemonic device: Keep Plates Clean Or Family Gets Sick.

Some of these categories can be further divided into intermediate categories such as subphyla, suborders, superfamilies, and superclasses. An example of this taxonomy scheme is:

Kingdom

Phylum
Subphylum
Superclass
Class
Subclass
Superorder
Order
Suborder
Superfamily
Family
Subfamily
Genus
Subgenus
Species
Subspecies

Below is a list of organisms and their classification in this taxonomy system using the major categories. Notice how closely related dogs and wolves are. They are similar in every aspect except species name.

Taxonomy of Organisms

Classification
		Brown Bear	House Cat	Dog	Killer Whale	Wolf
	Kingdom	Animalia	Animalia	Animalia	Animalia	Animalia
	Phylum	Chordata	Chordata	Chordata	Chordata	Chordata
	Class	Mammalia	Mammalia	Mammalia	Mammalia	Mammalia
	Order	Carnivora	Carnivora	Carnivora	Cetacea	Carnivora
	Family	Ursidae	Felidae	Canidae	Delphinidae	Canidae
	Genus	Ursus	Felis	Canis	Orcinus	Canis
	Species	Ursus arctos	Felis catus	Canis familiaris	Orcinus orca	Canis lupus