4.2.1 Defining the Science of Taxonomy

Taxonomy is defined as the classification and naming of things. Taxonomy organizes things into groups based on predefined criteria. The criteria can be as simple as color or height or as complex as the presence or absence of a trait, gene, or behavior. Taxonomy is a critical component of biological anthropology because it helps anthropologists organize humans and their evolutionary ancestors both spatially (by location) and temporally (through time).

Taxon refers to a specific subgroup, such as the genus. Taxa is the plural form of taxon, used to refer to all groups. The classification system used for organizing living organisms was originally developed in the 18th century by Swedish botanist Carolus Linnaeus. His system, which he called the Systema Naturae, uses a structure known as binomial nomenclature. Binomial nomenclature assigns two Latin names to each organism. The first is termed the genus name. The second is the specific or the trivial name, commonly called the species name. In print, genus and species names are italicized. The first letter of the genus is capitalized, while the species or trivial name is lowercase. For example, the scientific name for the house cat is Felis catus, and the name for modern human beings is Homo sapiens. Linnaeus’s binomial nomenclature established a shared scientific language that would become universal across countries and cultures, avoiding the confusion caused by regional and colloquial names.

In addition to establishing a shared language, Linnaeus’s naming system groups organisms that share common traits. For example, he grouped together animals with mammary glands into the category mammals. Mammals were further broken down according to other traits. For example, mammals that have opposable thumbs were grouped together as primates, and those without opposable thumbs were grouped as non-primates. This is a hierarchical classification scheme, meaning that organisms are grouped into successive levels from the broadest category of domain to the more specific level of species.

When Linnaeus first created his Systema Naturae, he built five hierarchical levels into his taxonomy: kingdom, class, order, genus, and species. Humans are in the kingdom Animalia, the class Mammalia, the order Primates, the genus Homo, and the species sapiens. Over time, many levels have been added to the Linnaean system of classification, including domain, phylum, subclass, superorder, family, and tribe. The addition of these taxon groups has enabled biological anthropologists to better understand the variations present in various groups of organisms. However, biological anthropologists spend the majority of their time trying to understand the species level.