Human taxonomy
Encyclopedia
Human taxonomy is the classification of the species
Homo sapiens (Latin
: "wise man"), or modern human. Homo
is the human genus
, which also includes Neanderthal
s and many other extinct species of hominid; H. sapiens is the only surviving species of the genus Homo. Extinct Homo species are known as archaic humans. Modern humans are the subspecies Homo sapiens sapiens
, differentiated from a direct ancestor, Homo sapiens idaltu
.
Prior to the current scientific classification of humans, philosophers and scientists have made various attempts to classify humans. They offered various definitions of the human being and various schemes for classifying types of humans. Biologists once classified races as subspecies, but today scientists question even the concept of race itself. Certain issues in human taxonomy remain topics of debate today.
) which have been interpolated between the seven traditional Linnaean taxonomic ranks
.
Humans are not only the sole surviving representatives of the genus Homo but also the only surviving representatives of the subtribe Hominina, which includes Australopithecus and other more anthropomorphic hominids. Species believed to be ancestors are listed within higher taxa.
Scientists have also debated whether any other branches of Homo, such as Neanderthals, should be classified as separate species or subspecies of H. sapiens. These distinctions are connected with two competing theories of human origins, the more common recent single-origin hypothesis (that modern humans represent a distinct gene pool) and the multiregional hypothesis (that modern humans spreading from Africa interbred with local Homo populations). Modern humans have some genes that originally arose in archaic human populations, composing perhaps 5% of our genetic inheritance. (For example, see microcephalin
.)
Species within the genus Homo are generally regarded as human. Australopithecines, too, are often referred to as human. Lay people sometimes ask whether the species other than H. sapiens were truly human. Were Neanderthals, for example, actually human or just close to human? This question makes sense in an essentalist philosophy, in which humans have an essential identity, and in which Neanderthals either did or did not share that identity. In religious context, the question might be phrased as "Did Neanderthals have souls?" In natural science, however, the term "human" is seen as a category whose boundaries humans themselves determine. The question, in this context, is not whether this or that species had the quality of being human in some absolute sense, but whether we choose to define the category of human as including that species.
, ancient Hebrews classified humans as a kind of living soul (nephesh
, roughly "breather"). Living things were said to beget their own kind, a group broader than the scientific species. Humans were said to comprise a single kind.
Humans have long been considered animals. Plato
referred to humans as featherless biped animals, and Aristotle
defined the human being as the "rational animal
" or the "political animal". Classic and medieval taxonomy grouped living things according to characteristics, and classifying humans as animals meant that they have various animal characteristics (moving, eating, breathing, etc.). Modern taxonomy, on the other hand, classifies organisms according to evolutionary lines of descent. Current opposition to classifying humans as animals arises from this modern definition of what it means to be an animal (that is, a descendent of a common animal ancestor that lived over 500 million years ago).
When Linnaeus defined humans as Homo sapiens in 1758, they were the only members of the genus Homo. The first other species to be classified a Homo was H. neanderthalensis, classified in 1864. Since then, ten additional extinct species have been classified as Homo.
In a common misunderstanding of evolutionary theory, each species represents a stage in the evolutionary track, some “more evolved” and others further behind. Based on this misunderstanding, scientists thought of humans as having descended from modern apes and expected to find the “missing link,” a living species halfway between apes and humans.
). This concept was so powerful when Europeans discovered the New World some of them considered the indigenous peoples to be soulless animals
.
Races were once considered human subspecies, but genetic research shows that inherited differences do not accurately match common racial divisions. For example, since non-Africans are descended from a small population that emigrated from Africa about 100,000 years ago, non-Africans (even those representing difference races) are more closely related to each other than Africans are to each other.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
Homo sapiens (Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
: "wise man"), or modern human. Homo
Homo (genus)
Homo is the genus that includes modern humans and species closely related to them. The genus is estimated to be about 2.3 to 2.4 million years old, evolving from australopithecine ancestors with the appearance of Homo habilis....
is the human genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
, which also includes Neanderthal
Neanderthal
The Neanderthal is an extinct member of the Homo genus known from Pleistocene specimens found in Europe and parts of western and central Asia...
s and many other extinct species of hominid; H. sapiens is the only surviving species of the genus Homo. Extinct Homo species are known as archaic humans. Modern humans are the subspecies Homo sapiens sapiens
Human
Humans are the only living species in the Homo genus...
, differentiated from a direct ancestor, Homo sapiens idaltu
Homo sapiens idaltu
Homo sapiens idaltu is an extinct subspecies of Homo sapiens that lived almost 160,000 years ago in Pleistocene Africa. is from the Saho-Afar word meaning "elder or first born"....
.
Prior to the current scientific classification of humans, philosophers and scientists have made various attempts to classify humans. They offered various definitions of the human being and various schemes for classifying types of humans. Biologists once classified races as subspecies, but today scientists question even the concept of race itself. Certain issues in human taxonomy remain topics of debate today.
Extended scientific classification
The modern scientific classification of the human species contains many sub- and super- sections (each one being, ideally, a cladeClade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
) which have been interpolated between the seven traditional Linnaean taxonomic ranks
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
.
Humans are not only the sole surviving representatives of the genus Homo but also the only surviving representatives of the subtribe Hominina, which includes Australopithecus and other more anthropomorphic hominids. Species believed to be ancestors are listed within higher taxa.
- BiotaBiota (taxonomy)In some systems of scientific classification, Biota, Vitae, Eobionti is the superdomain that classifies all life. For that reason it is often disputed how the taxon should be further divided, as the definition of "what life really is" is often changed or adjusted, and also extraterrestrial life...
[all life on Earth, including precellular life] - Clade - Cytota [all cellular life; LUCA, Prokarya, Bacteria]
- Clade - NeomuraNeomuraNeomura is a clade composed of the two domains of life of Archaea and Eukaryota. The group was first proposed by Thomas Cavalier-Smith and its name means "new walls"; so called because it is thought to have evolved from Bacteria, and one of the major changes was the replacement of peptidoglycan...
[like Archaea, also included, oldest neomura, common ancestor with them] - Domain - Eukarya [like Bikonta, also included, oldest eukaryotes, common ancestor with them; cellular nucleus; first eukaryotic multicellular organisms; plants]
- Clade - Unikonta [only one flagellum; like Amoebozoa, also included, common ancestor with them]
- Clade - OpisthokontOpisthokontThe opisthokonts or "Fungi/Metazoa group" are a broad group of eukaryotes, including both the animal and fungus kingdoms, together with the eukaryotic microorganisms that are sometimes grouped in the paraphyletic phylum Choanozoa...
a [like Fungi, also included, oldest opisthokonts, common ancestor with them] - Clade - HolozoaHolozoaHolozoa is a group of organisms that includes animals and their closest single-celled relatives, but excludes fungi. Holozoa is also an old name for the tunicate genus Distaplia....
- Clade - FilozoaFilozoaThe Filozoa are a monophyletic grouping within the Opisthokonta. They include animals along with their nearest unicellular relatives ....
- Kingdom - Animalia/Metazoa
- Subkingdom - EumetazoaEumetazoaEumetazoa is a clade comprising all major animal groups except sponges, placozoa and several other little known animals. Characteristics of eumetazoans include true tissues organized into germ layers, and an embryo that goes through a gastrula stage...
[remotest origin of animal motility] - Clade - BilateriaBilateriaThe bilateria are all animals having a bilateral symmetry, i.e. they have a front and a back end, as well as an upside and downside. Radially symmetrical animals like jellyfish have a topside and downside, but no front and back...
[having bilateral symmetry] - Superphylum - Deuterostomia [anus gets formed first, and mouth gets formed opposedly and after]
- Phylum - ChordataChordateChordates are animals which are either vertebrates or one of several closely related invertebrates. They are united by having, for at least some period of their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail...
- Clade - CraniataCraniataCraniata is a proposed clade of chordate animals that contains the Myxini , Petromyzontida , and Gnathostomata as living representatives...
[animals with skulls] - Subphylum - Vertebrata [...and backbones]
- Infraphylum - GnathostomataGnathostomataGnathostomata is the group of vertebrates with jaws. The term derives from Greek γνάθος "jaw" + στόμα "mouth". Gnathostome diversity comprises roughly 60,000 species, which accounts for 99% of all living vertebrates...
[...and jaws] - Superclass - OsteichthyesOsteichthyesOsteichthyes , also called bony fish, are a taxonomic group of fish that have bony, as opposed to cartilaginous, skeletons. The vast majority of fish are osteichthyes, which is an extremely diverse and abundant group consisting of over 29,000 species...
- Class - SarcopterygiiSarcopterygiiThe Sarcopterygii or lobe-finned fishes – sometimes considered synonymous with Crossopterygii constitute a clade of the bony fishes, though a strict classification would include the terrestrial vertebrates...
[Includes lobe-finned fish and all land vertebrates.] - Infraclass - TetrapodomorphaTetrapodomorphaTetrapodomorpha is a clade of vertebrates, consisting of tetrapods and their closest sarcopterygian relatives that are more closely related to living tetrapods than to living lungfish...
- Superclass - Tetrapoda [...and four limbs for terrestrial locomotion]
- Clade - Amniota [...and amniotic eggs ("terrestrial" eggs)]
- Subclass - Synapsida
- Order - TherapsidaTherapsidaTherapsida is a group of the most advanced synapsids, and include the ancestors of mammals. Many of the traits today seen as unique to mammals had their origin within early therapsids, including hair, lactation, and an erect posture. The earliest fossil attributed to Therapsida is believed to be...
- Clade - Theriodontia
- Suborder - Cynodontia
- Clade - Epicynodontia
- Infraorder - EucynodontiaEucynodontiaEucynodontia is a grouping of animals that includes both mammals, such as dogs, and mammal-like non-mammalian therapsids such as cynodonts . Its membership was and is made up of both carnivores and herbivores. The chronological range extends from at least the Lower Triassic, possibly the Upper...
- Clade - ProbainognathiaProbainognathiaThe Probainognathians are one of the two major clades of the infraorder Eucynodontia, the other being Cynognathians. They were mostly carnivorous, though some species may have evolved omnivorous traits. The Probainognathia form into four groups: Probainognathidae, Chiniquodontidae,...
- Clade - ChiniquodontoideaChiniquodontoideaChiniquodontoidea is a clade of cynodonts that is defined as including all probainognathians closer to mammals than to Probainognathus which is the more primitive form in Probainognathia....
- Clade - Mamaliamorpha
- Clade - MammaliaformesMammaliaformesMammaliaformes is a clade that contains the mammals and their closest extinct relatives. Phylogenetically, it is defined as a clade including the most recent common ancestor of Sinoconodon, morganuconodonts, docodonts, Monotremata, Marsupialia, Placentalia, extinct members of this clade, and all...
- Class - Mammalia [all mammals]
- Subclass - Theriiformes
- Infraclass - Holotheria
- Superlegion - TrechnotheriaTrechnotheriaTrechnotheria is a group of mammals that includes the therians and some fossil mammals from the Mesozoic Era. In the Jurassic through Cretaceous periods, the group was endemic to what would be Asia and Africa...
- Legion - CladotheriaCladotheriaCladotheria is a group of mammals that is defined as including the ancestor of Dryolestoidea, Peramuridae and Zatheria .-External links:* * -Further reading:Zofia Kielan-Jaworowska, Richard L...
- Sublegion - ZatheriaZatheriaZatheria is a group of mammals that is defined as including the ancestor of Arguitheriidae, Arguimuridae, Vincelestidae, Peramuridae and Tribosphenida .-External links:* *...
- Infralegion - TribosphenidaTribosphenidaTribosphenida is a group of mammals that is defined as including the ancestor of Hypomylos, Necrolestidae, Aegialodontia and supercohort Theria .-External links:* * * -Further reading:...
- Supercohort - TheriaTheriaTheria is a subclass of mammals that give birth to live young without using a shelled egg, including both eutherians and metatherians . The only omitted extant mammal group is the egg-laying monotremes....
- Cohort - EutheriaEutheriaEutheria is a group of mammals consisting of placental mammals plus all extinct mammals that are more closely related to living placentals than to living marsupials . They are distinguished from noneutherians by various features of the feet, ankles, jaws and teeth...
- Magnorder - BoreoeutheriaBoreoeutheriaBoreoeutheria is a clade of placental mammals that is composed of the sister taxa Laurasiatheria and Euarchontoglires...
- Superorder - EuarchontogliresEuarchontogliresEuarchontoglires is a clade of mammals, the living members of which are rodents, lagomorphs, treeshrews, colugos and primates .-Evolutionary relationships:...
- Grandorder - EuarchontaEuarchontaThe Euarchonta are a grandorder of mammals containing four orders: the Dermoptera or colugos, the Scandentia or treeshrews, the extinct Plesiadapiformes, and the Primates....
- Epiorder - PrimatomorphaPrimatomorphaThe Primatomorpha are a mirorder of mammals containing two orders: the Dermoptera or colugos and the Primates ....
- Order - Primates [arboreal prehensile locomotion; terrestrial bipedal leaping in some cases; Strepsirrhini, Prosimians, also included, oldest living primates, common ancestor with them]
- Suborder - HaplorrhiniHaplorrhiniThe haplorhines, the "dry-nosed" primates , are members of the Haplorhini clade: the prosimian tarsiers and the anthropoids...
[anthropoidea; like Tarsiiformes, also included, oldest living haplorrhini, common ancestor with them] - Infraorder - Simiiformes [earliest documented tool ethology; like Platyrrhini, American Monkeys, also included, oldest living simiiformes; monkeys and apes included here]
- Parvorder - CatarrhiniCatarrhiniCatarrhini is one of the two subdivisions of the higher primates . It contains the Old World monkeys and the apes, which in turn are further divided into the lesser apes or gibbons and the great apes, consisting of the orangutans, gorillas, chimpanzees, bonobos, and humans...
[land extended locomotion; like Cercopithecoidea, Old World Monkeys, also included, oldest living ones] - Superfamily - Hominoidea [tail loss, arboreal locomotion reduced to forelimbs (Brachiation); apes, lesser apes, hominoids; like Hylobatidae, Gibbons, also included, oldest living ones]
- Species - Proconsul africanusProconsul africanusProconsul africanus is the first species of the oligocene-era fossil genus of primate to be discovered and was named by Arthur Hopwood, an associate of Louis Leakey, in 1933.- Discovery :...
- Family - HomieHomieHomie or homey is a slang term in urban culture whose origins etymologists generally trace to African American language from the late 19th century. This was a time when many African Americans were migrating to cities in larger numbers, and "homeboy" meant a male friend from back home. It was...
[great apes, hominids; fist-walking; family with Ponginae, Orangutans, also included, oldest living ones, common ancestor with them] - Subfamily - HomininaeHomininaeHomininae is a subfamily of Hominidae, which includes humans, gorillas and chimpanzees, and some extinct relatives; it comprises all those hominids, such as Australopithecus, that arose after the split from orangutans . Our family tree, which has 3 main branches leading to chimpanzees, humans and...
[or hominines; knuckle-walking; includes gorillas but not orangutans]
- Species - Pierolapithecus catalaunicusPierolapithecus catalaunicusPierolapithecus catalaunicus is an extinct species of primate which lived about 13 million years ago during the Miocene in what is now Hostalets de Pierola, Catalonia giving the name to the species...
- Tribe - HomininiHomininiHominini is the tribe of Homininae that comprises Homo, and the two species of the genus Pan , their ancestors, and the extinct lineages of their common ancestor . Members of the tribe are called hominins...
[or hominins; includes chimpanzees but not gorillas]
- Tribe - Hominini
- Species - Sahelanthropus tchadensisSahelanthropus tchadensisSahelanthropus tchadensis is an extinct hominid species that is dated to about . Whether it can be regarded as part of the Hominina tree is unclear; there are arguments both supporting and rejecting it...
, possible common ancestor with chimpanzees - Species - Orrorin tugenensisOrrorin tugenensisOrrorin tugenensis is considered to be the second-oldest known hominin ancestor that is possibly related to modern humans, and it is the only species classified in genus Orrorin...
, may be an early species after split with chimpanzees- Subtribe - HomininaHomininaThe more anthropomorphic primates of the Hominini tribe are placed in the Hominina subtribe. Referred to as hominans, they are characterized by the evolution of an increasingly erect bipedal locomotion. The only extant species is Homo sapiens...
[or hominans; orthograde (upright) bipedalism; humans are the only surviving species]
- Subtribe - Hominina
- Genus - ArdipithecusArdipithecusArdipithecus is a very early hominin genus. Two species are described in the literature: A. ramidus, which lived about 4.4 million years ago during the early Pliocene, and A. kadabba, dated to approximately 5.6 million years ago ....
[Human lineage] - Genus - Kenyanthropus
- Genus - AustralopithecusAustralopithecusAustralopithecus is a genus of hominids that is now extinct. From the evidence gathered by palaeontologists and archaeologists, it appears that the Australopithecus genus evolved in eastern Africa around 4 million years ago before spreading throughout the continent and eventually becoming extinct...
[Human lineage; made tools found]
- Genus - HomoHomo (genus)Homo is the genus that includes modern humans and species closely related to them. The genus is estimated to be about 2.3 to 2.4 million years old, evolving from australopithecine ancestors with the appearance of Homo habilis....
[or humans; specific and specialized development of memory/learning/teaching/learning application (learning driven ethology)]
- Species - Homo habilisHomo habilisHomo habilis is a species of the genus Homo, which lived from approximately at the beginning of the Pleistocene period. The discovery and description of this species is credited to both Mary and Louis Leakey, who found fossils in Tanzania, East Africa, between 1962 and 1964. Homo habilis Homo...
[refined stone technology; earliest fire control] - Species - Homo ergasterHomo ergasterHomo ergaster is an extinct chronospecies of Homo that lived in eastern and southern Africa during the early Pleistocene, about 2.5–1.7 million years ago.There is still disagreement on the subject of the classification, ancestry, and progeny of H...
[extensive language, complex articulate language] - Species - Homo erectusHomo erectusHomo erectus is an extinct species of hominid that lived from the end of the Pliocene epoch to the later Pleistocene, about . The species originated in Africa and spread as far as India, China and Java. There is still disagreement on the subject of the classification, ancestry, and progeny of H...
[fire control, cooking; aesthetic/artistic refinement of tools] - Species - Homo heidelbergensisHomo heidelbergensisHomo heidelbergensis is an extinct species of the genus Homo which may be the direct ancestor of both Homo neanderthalensis in Europe and Homo sapiens. The best evidence found for these hominins date between 600,000 and 400,000 years ago. H...
[possible earliest sanitary burial of deads, accompanied with symbolic/formal supplement]
- Species - Homo sapiens [further development and specialization of learning application; active environment transformation, acclimatization and control; infrastructures and advanced technology]
- Subspecies - Homo sapiens idaltuHomo sapiens idaltuHomo sapiens idaltu is an extinct subspecies of Homo sapiens that lived almost 160,000 years ago in Pleistocene Africa. is from the Saho-Afar word meaning "elder or first born"....
- Subspecies - Homo sapiens sapiensHumanHumans are the only living species in the Homo genus...
- Subspecies - Homo sapiens sapiens
Current issues in human taxonomy
Generally, humans are considered the only surviving representatives of the genus Homo. Some scientists, however, consider other members of the hominid family (chimpanzees, bonobos, and gorillas) to be so close to humans genetically that they should be classified as Homo.Scientists have also debated whether any other branches of Homo, such as Neanderthals, should be classified as separate species or subspecies of H. sapiens. These distinctions are connected with two competing theories of human origins, the more common recent single-origin hypothesis (that modern humans represent a distinct gene pool) and the multiregional hypothesis (that modern humans spreading from Africa interbred with local Homo populations). Modern humans have some genes that originally arose in archaic human populations, composing perhaps 5% of our genetic inheritance. (For example, see microcephalin
Microcephalin
Microcephalin is one of six genes causing primary microcephaly when non-functional mutations exist in the homozygous state...
.)
Species within the genus Homo are generally regarded as human. Australopithecines, too, are often referred to as human. Lay people sometimes ask whether the species other than H. sapiens were truly human. Were Neanderthals, for example, actually human or just close to human? This question makes sense in an essentalist philosophy, in which humans have an essential identity, and in which Neanderthals either did or did not share that identity. In religious context, the question might be phrased as "Did Neanderthals have souls?" In natural science, however, the term "human" is seen as a category whose boundaries humans themselves determine. The question, in this context, is not whether this or that species had the quality of being human in some absolute sense, but whether we choose to define the category of human as including that species.
History of human taxonomy
Human taxonomy has involved both placing humans within the hominid family (or within the animal kingdom in general) and classifying types of humans within the species.History of classifying the human species
As recorded in the Hebrew BibleHebrew Bible
The Hebrew Bible is a term used by biblical scholars outside of Judaism to refer to the Tanakh , a canonical collection of Jewish texts, and the common textual antecedent of the several canonical editions of the Christian Old Testament...
, ancient Hebrews classified humans as a kind of living soul (nephesh
Nephesh
The Bible portrays the concept of Soul most commonly using the Hebrew word nephesh and the Greek word psyche.The Greek Septuagint mostly uses psyche to translate nephesh...
, roughly "breather"). Living things were said to beget their own kind, a group broader than the scientific species. Humans were said to comprise a single kind.
Humans have long been considered animals. Plato
Plato
Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...
referred to humans as featherless biped animals, and Aristotle
Aristotle
Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...
defined the human being as the "rational animal
Rational Animal
Rational animal is a classical definition of man. Though it is often attributed to first appearing as a definition in Aristotle's Metaphysics, Aristotle does not define it here...
" or the "political animal". Classic and medieval taxonomy grouped living things according to characteristics, and classifying humans as animals meant that they have various animal characteristics (moving, eating, breathing, etc.). Modern taxonomy, on the other hand, classifies organisms according to evolutionary lines of descent. Current opposition to classifying humans as animals arises from this modern definition of what it means to be an animal (that is, a descendent of a common animal ancestor that lived over 500 million years ago).
When Linnaeus defined humans as Homo sapiens in 1758, they were the only members of the genus Homo. The first other species to be classified a Homo was H. neanderthalensis, classified in 1864. Since then, ten additional extinct species have been classified as Homo.
In a common misunderstanding of evolutionary theory, each species represents a stage in the evolutionary track, some “more evolved” and others further behind. Based on this misunderstanding, scientists thought of humans as having descended from modern apes and expected to find the “missing link,” a living species halfway between apes and humans.
History of classifying types of humans
Europeans in the Middle Ages considered humanity to be divided into three races, one for each of the sons of Noah (see JapheticJaphetic
Japhetic is a term that refers to the supposed descendants of Japheth, one of the three sons of Noah in the Bible. It corresponds to Semitic and Hamitic...
). This concept was so powerful when Europeans discovered the New World some of them considered the indigenous peoples to be soulless animals
Sublimus Dei
Sublimus Dei is a papal bull promulgated by Pope Paul III on June 2, 1537, which forbids the enslavement of the indigenous peoples of the Americas and all other people...
.
Races were once considered human subspecies, but genetic research shows that inherited differences do not accurately match common racial divisions. For example, since non-Africans are descended from a small population that emigrated from Africa about 100,000 years ago, non-Africans (even those representing difference races) are more closely related to each other than Africans are to each other.