The mother of all great apes lived about 14 million years ago. Over time, the descendants of this grand primate diverged into two species: one that evolved into the modern orangutan, and one that was the common ancestor of gorillas, humans, chimpanzees, and bonobos. This latter creature lived for around 7 million years before its line also split into two paths, one of which led to the modern gorilla and one that led to humans, chimpanzees, and bonobos. The common ancestor of humans, chimpanzees, and bonobos lived about 6 million years ago, after which the line that led to humans split away. The human lineage threw up at least twenty different types of hominids only one of which survives today, Homo sapiens sapiens. The other line split again a million or so years later and led to the species… that exist today, the common chimpanzee, and bonobo, found only in Zaire.
— Christine Kenneally, The First Word

Taxonomy: classification, especially in relation to its general laws or principles; the branch of science, or of a particular science or subject, that deals with classification; especially the systematic classification of living “organisms.” (Oxford) The field of biology that is concerned with the theory, practice, and rules of classifying living and extinct organisms and "viruses." Results in the ordered division of "species" into groups based on similarities and dissimilarities in their characteristics. (Brooker, 537) The scientific study of classification. (Cardwell, 265) Editor’s note - an example taxonomy for people would be:


Domain: eukarya.

Kingdom: animalia, members animals.

Phylum: chordata.

Class: mammalia, members mammals.

Order: primate, members primates.

Family: hominidae, members hominids.

Genus: homo.

Species: homo sapiens.

Homo Sapiens first appearance on Earth (came) about 200,00 years ago. (Merzenich, 12) Although humans and chimps differ remarkably in appearances and behavior, they share some 98.8 percent of their genetic identity. With the successful sequencing of the “human genome” and, more recently, the 'chimp genome,' geneticists are beginning to scan regions of those genomes for differences and even starting to identify the precise function of specific genes. Still, the exact nature of the last common ancestor of chimps and humans remains a mystery. (Johanson, 272) Adjective - 'taxonomic.'

Class: a subdivision of a phylum. (Brooker, G-7) It is a major group of organisms, e.g. ‘mammalia,’  ‘reptilia,’  ‘gastropoda,’  ‘Insecta,’ etc that contains a large number of different ‘sublineages,’ but have shared characteristics in common (e.g. warm-blooded, fur, six legs etc.) (NCIt)

Domain: one of the three major categories of life: “bacteria,” “archaea,” or “eukarya.” (Brooker, G-11) The highest level of biological classification. (Lawrence) Also referred to as 'super kingdom.'

Domain Archaea: one of the three domains of life, formerly called ‘Archaebacteria’ under the taxon ‘Bacteria,’ but now considered separate and distinct. Genome sequencing confirmed that this organism represents a third form of life. (Lewis, 431) Discovered by Carl Woese, of the University of Illinois in 1977. (Venter, 56)

Domain Bacteria: One of the three domains of life. (MeSH) Any of a very widely distributed group of microscopic mainly single-celled organisms. (Oxford)

Domain Eukarya: the organisms in domain Eukarya have been further subdivided into major categories or ‘kingdoms’ called ‘Animalia,’ ‘Plantae’ (plants), Protista (protists), and Fungi. This (domain) is now under revision. (Brooker, 8) Also referred to as 'eukaryotes.'

Family: a level of classification. (Indge, 107) A taxonomic category between "order" and "genus." It consists of a group of organisms among which the differences are quite minor, e.g. 'equiidae' - horses and their relatives. (NCIt) Taxonomic group of related families being grouped into "orders." Family names usually end in -idae in animals. (Lawrence)

Genus: a subdivision of a family. (Brooker, G-16) Taxonomic group of closely related species, (with) similar and related 'genera' being grouped into families. Generic names are italicized in the scientific literature, e.g. Homo (human), Canis (dogs and wolves.) (Lawrence) The scientific name given to a species contains two words. The first word gives the name of the genus and the second, the name of the species. (e.g. Homo sapiens.) (Indge, 122) Plural - 'genera.'

Kingdom: a “taxonomic” group that contains one or more “phyla.” (Brooker, G-20) The highest taxonomic rank, immediately above "phylum" or division. There are (several) biological kingdoms into which organisms are grouped, based on common characteristics. (NCIt)

Kingdom Animalia: multicellular organisms that usually have a “nervous system” and are capable of locomotion. They must eat other organisms to live. (Booker, 9) Unlike the cells of bacteria, fungi, and plants, the cells of animals are not surrounded by a rigid cell wall that provides structure and support. However, animal cells secrete materials that form an “extracellular matrix” that serves a similar purpose. (Booker, 192)

Kingdom Fungi: unicellular and multicellular organisms that have a cell wall but cannot carry out “photosynthesis.” Fungi usually survive on decaying organic material. (Booker, 9)

Kingdom Plantae: multicellular organisms that can carry out 'photosynthesis.' (Booker, 9)

Kingdom Protista: unicellular and small multicellular organisms that are now subdivided into several different kingdoms based on their evolutionary relationship. (Booker, 9)

Order: a subdivision of a class. (Brooker, G-26) A taxonomic category between Class and Family. It is a group of organisms that, although differing quite a bit among themselves, still have a large degree of characteristics in common. (NCIt)

Phylum: the subdivision of a kingdom. (Brooker, G-29) Of or pertaining to the evolutionary development of a species or other taxonomic grouping. (Oxford) A primary grouping consisting of animals constructed on a similar general plan, and thought to be evolutionarily related. In plants, the similar category is called a 'division.' Examples: Proifera (sponges), Anthropoda (spiders, insects, crustaceans) and Chordata (includes the vertebrates). (Lawrence) Adjective - ‘phyletic.’ Plural - 'phyla.' 

Species: a related group of organisms that share a distinctive form and set of attributes in nature. (Brooker, 4) Similar organisms which are able to breed together and produce fertile offspring. (Indge, 252) Not normally able to interbreed with with such groups. Species can be subdivided into 'subspecies' and 'geographic races.' and varieties. (Lawrence)