Anatomy & Physiology For Dummies
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Taxonomy is the science that seeks to classify and organize living things, expressed as a series of mutually exclusive categories. The highest (most inclusive) category is domain, of which there are three: Archea, Eubacteria, Eukaryota. Each of these domains is split into kingdoms, which are further divided until each individual organism is its own unique species.

Outside of bacteria, all living things fall under the Eukaryota domain; the kingdoms are: Protista, Fungi, Plantae, and Animalia. Within each kingdom, the system classifies each organism into the hierarchical subgroups (and sometimes sub-subgroups) of phylum, class, order, family, genus, and species. Here's the breakdown of humankind:

Kingdom Animalia: All animals.

Phylum Chordata: Animals that have a number of structures in common, particularly the notochord, a rodlike structure that forms the body's supporting axis.

  • Subphylum Vertebrata: Animals with backbones.
  • Superclass Tetrapoda: Four-footed vertebrates.
Class Mammalia: Tetrapods with hair. Other classes of the vertebrata are Pisces (fish), Amphibia (frogs), Aves (birds), and Reptilia (scaly things).

Order Primates: Mammals with more highly developed brains, flexible hips and shoulders, and prehensile hands and feet (able to grasp).

  • Superfamily Hominoidea: Apes (chimpanzees, gorillas, orangutans, humans).
Family Hominidae: Great apes, including humans.

Genus Homo: The human species is the only surviving species of our genus, though this genus included several species in the evolutionary past.

Species Sapiens: All species are given a two-part Latin name, in which the genus name comes first and a species epithet comes second. The biologists who name species sometimes try to use a descriptor in the epithet. For humans, they could have chosen "bipedal" or "talking" or "hairless," but they chose "thinker."

  • Variety Sapiens: Some species get a "varietal" name, usually indicating a difference that's obvious but not necessarily important from an evolutionary point of view. The human species has one other variety, Homo sapiens neanderthalensis, which has been extinct for tens of thousands of years. All humans living since then are of one species variety, Homo sapiens sapiens. In the evolutionary classification of humans, there's no biologically valid category below species variety.

About This Article

This article is from the book:

About the book authors:

Erin Odya is an anatomy and physiology teacher at Carmel High School in Carmel, Indiana, one of Indiana’s top schools.

Maggie Norris is a freelance science writer living in the San Francisco Bay Area.

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