Numerous revisions in classifying the great apes have caused the use of the termhominid to change over time. The original meaning of "hominid" referred only to humans (Homo) and their closest extinct relatives. However, by the 1990s humans and other apes were considered to be "hominids".
The earlier restrictive meaning has now been largely assumed by the termhominin, which comprises all members of the human clade after the split from the chimpanzees (Pan). The current meaning of "hominid" includes all the great apes including humans. Usage still varies, however, and some scientists and laypersons still use "hominid" in the original restrictive sense; the scholarly literature generally shows the traditional usage until the turn of the 21st century.[5]
Within the taxon Hominidae, a number of extant and extinct genera are grouped with the humans, chimpanzees, and gorillas in the subfamilyHomininae; others with orangutans in the subfamilyPonginae (seeclassification graphic below). Themost recent common ancestor of all Hominidae lived roughly 14 million years ago,[6] when the ancestors of the orangutans speciated from the ancestral line of the other three genera.[7] Those ancestors of the family Hominidae had already speciated from the familyHylobatidae (thegibbons), perhaps 15 to 20 million years ago.[7][8]
Due to the close genetic relationship between humans and the other great apes, certainanimal rights organizations, such as theGreat Ape Project, argue that nonhumangreat apes are persons and should be given basichuman rights. Twenty-nine countries have institutedresearch bans to protect great apes from any kind of scientific testing.[9]
At sites far distant from East Africa, the presence of other generalized non-cercopithecids, that is, non-monkey primates, of middle Miocene age—Otavipithecus from cave deposits in Namibia, andPierolapithecus andDryopithecus from France, Spain and Austria—is further evidence of a wide diversity of ancestral ape forms across Africa and the Mediterranean basin during the relatively warm and equable climatic regimes of the early and middle Miocene. The most recent of these far-flung Miocene apes (hominoids) isOreopithecus, from the fossil-rich coal beds in northern Italy and dated to 9 million years ago.
Molecular evidence indicates that the lineage of gibbons (family Hylobatidae), the "lesser apes", diverged from that of the great apes some 18–12 million years ago, and that of orangutans (subfamily Ponginae) diverged from the other great apes at about 12 million years. There are no fossils that clearly document the ancestry of gibbons, which may have originated in a still-unknown South East Asian hominoid population; but fossil proto-orangutans, dated to around 10 million years ago, may be represented bySivapithecus from India andGriphopithecus from Turkey.[10] Species close to the last common ancestor of gorillas, chimpanzees and humans may be represented byNakalipithecus fossils found in Kenya andOuranopithecus fossils found inGreece. Molecular evidence suggests that between 8 and 4 million years ago, first the gorillas (genusGorilla), and then the chimpanzees (genusPan) split off from the line leading to humans. HumanDNA is approximately 98.4% identical to that of chimpanzees when comparing single nucleotide polymorphisms (seehuman evolutionary genetics).[11] The fossil record, however, of gorillas and chimpanzees is limited; both poor preservation—rain forest soils tend to be acidic and dissolve bone—andsampling bias probably contribute most to this problem.
Otherhominins probably adapted to the drier environments outside the African equatorial belt; and there they encountered antelope, hyenas, elephants and other forms becoming adapted to surviving in the East Africansavannas, particularly the regions of theSahel and theSerengeti. The wet equatorial belt contracted after about 8 million years ago, and there is very little fossil evidence for the divergence of the hominin lineage from that of gorillas and chimpanzees—which split was thought to have occurred around that time. The earliest fossils argued by some to belong to the human lineage areSahelanthropus tchadensis (7 Ma) andOrrorin tugenensis (6 Ma), followed byArdipithecus (5.5–4.4 Ma), with speciesAr. kadabba andAr. ramidus.
The classification of the great apes has beenrevised several times in the last few decades; these revisions have led to a varied use of the word "hominid" over time. The original meaning of the term referred to only humans and their closest relatives—what is now the modern meaning of the term "hominin". The meaning of thetaxon Hominidae changed gradually, leading to a modern usage of "hominid" that includes all the great apes including humans.
A number of very similar words apply to related classifications:
Ahominoid, sometimes called anape, is a member of the superfamilyHominoidea: extant members are the gibbons (lesser apes, family Hylobatidae) and the hominids.
Ahominid is a member of the family Hominidae, the great apes: orangutans, gorillas, chimpanzees and humans.
Ahominine is a member of the subfamilyHomininae: gorillas, chimpanzees, and humans (excludes orangutans).
Ahominin is a member of the tribeHominini: chimpanzees and humans.[12]
Ahomininan, following a suggestion by Wood and Richmond (2000), would be a member of the subtribeHominina of the tribeHominini: that is, modern humans and their closest relatives, includingAustralopithecina, but excluding chimpanzees.[13][14]
Ahuman is a member of the genusHomo, of whichHomo sapiens is the only extant species, and within thatHomo sapiens sapiens is the only survivingsubspecies.
Hominidae was originally the name given to the family of humans and their (extinct) close relatives, with the other great apes (that is, the orangutans, gorillas and chimpanzees) all being placed in a separate family, thePongidae. However, that definition eventually made Pongidaeparaphyletic because at least one great ape species (the chimpanzees) proved to be more closely related to humans than to other great apes. Most taxonomists today encouragemonophyletic groups—this would require, in this case, the use of Pongidae to be restricted to just one closely related grouping. Thus, manybiologists now assignPongo (as thesubfamilyPonginae) to the family Hominidae. The taxonomy shown here follows the monophyletic groupings according to the modern understanding of human and great ape relationships.
Humans and close relatives including the tribesHominini andGorillini form the subfamilyHomininae (see classification graphic below). (A few researchers go so far as to refer the chimpanzees and the gorillas to the genusHomo along with humans.)[15][16][17] But, those fossil relatives more closely related to humans than the chimpanzees represent the especially close members of the human family,and without necessarily assigning subfamily or tribal categories.[clarification needed][18]
The exact criteria for membership in the tribe Hominini under the current understanding of human origins are not clear, but the taxon generally includes thosespecies that share more than 97% of theirDNA with the modern humangenome, and exhibit a capacity forlanguage or for simplecultures beyond their 'local family' or band. Thetheory of mind concept—including such faculties as empathy, attribution of mental state, and even empathetic deception—is a controversial criterion; it distinguishes the adult human alone among the hominids. Humans acquire this capacity after about four years of age, whereas it has not been proven (nor has it been disproven) that gorillas or chimpanzees ever develop a theory of mind.[20] This is also the case for someNew World monkeys outside the family of great apes, as, for example, thecapuchin monkeys.
However, even without the ability to test whether early members of the Hominini (such asHomo erectus,Homo neanderthalensis, or even the australopithecines) had a theory of mind, it is difficult to ignore similarities seen in their living cousins. Orangutans have shown the development of culture comparable to that of chimpanzees,[21] and some[who?] say the orangutan may also satisfy those criteria for thetheory of mind concept. These scientific debates take on political significance for advocates ofgreat ape personhood.
Description
Gorilla
The great apes are tailless primates, with the smallest living species being the bonobo at 30 to 40 kilograms (66 to 88 lb) in weight, and the largest being the eastern gorillas, with males weighing 140 to 180 kilograms (310 to 400 lb). In all great apes, the males are, on average, larger and stronger than the females, although the degree ofsexual dimorphism varies greatly among species. Hominid teeth are similar to those of theOld World monkeys and gibbons, although they are especially large in gorillas. Thedental formula is2.1.2.32.1.2.3. Human teeth and jaws are markedly smaller relative to body size compared to those of other apes. This may be an adaptation not only to the extensive use of tools, which has supplanted the role of jaws in hunting and fighting, but also to eating cooked food since the end of thePleistocene.[22][23]
Behavior
Although most living species are predominantlyquadrupedal, they are all able to use their hands for gathering food or nesting materials, and, in some cases, for tool use.[24] They build complex sleeping platforms, also called nests, in trees to sleep in at night, but chimpanzees and gorillas also build terrestrial nests, and gorillas can also sleep on the bare ground.[25]
All species areomnivorous,[26] although chimpanzees and orangutans primarily eat fruit. When gorillas run short of fruit at certain times of the year or in certain regions, they resort to eating shoots and leaves, often ofbamboo, a type of grass. Gorillas have extreme adaptations for chewing and digesting such low-quality forage, but they still prefer fruit when it is available, often going miles out of their way to find especially preferred fruits. Humans, since theNeolithic Revolution, have consumed mostlycereals and otherstarchy foods, including increasingly highlyprocessed foods, as well as many otherdomesticated plants (including fruits) andmeat.
Both chimpanzees and humans are known to wagewars over territories and resources.[27]
Gestation in great apes lasts 8–9 months, and results in the birth of a single offspring, or, rarely, twins. The young are born helpless, and require care for long periods of time. Compared with most other mammals, great apes have a remarkably long adolescence, not beingweaned for several years,[28] and not becoming fully mature for eight to thirteen years in most species (longer in orangutans and humans). As a result, females typically give birth only once every few years. There is no distinct breeding season.[24]
Gorillas and chimpanzees live in family groups of around five to ten individuals, although much larger groups are sometimes noted. Chimpanzees live in larger groups that break up into smaller groups when fruit becomes less available. When small groups of female chimpanzees go off in separate directions to forage for fruit, the dominant males can no longer control them and the females often mate with other subordinate males. In contrast, groups of gorillas stay together regardless of the availability of fruit. When fruit is hard to find, they resort to eating leaves and shoots.
This fact is related to gorillas' greater sexual dimorphism relative to that of chimpanzees; that is, the difference in size between male and female gorillas is much greater than that between male and female chimpanzees. This enables gorilla males to physically dominate female gorillas more easily. In both chimpanzees and gorillas, the groups include at least one dominant male, and young males leave the group at maturity.
Due to the close genetic relationship between humans and the other great apes, certainanimal rights organizations, such as theGreat Ape Project, argue that nonhumangreat apes are persons and, per theDeclaration on Great Apes, should be given basichuman rights. In 1999, New Zealand was the first country to ban any great ape experimentation, and now 29 countries have currently instituted aresearch ban to protect great apes from any kind of scientific testing.
On 25 June 2008, the Spanish parliament supported a new law that would make "keeping apes for circuses, television commercials or filming" illegal.[29] On 8 September 2010, theEuropean Unionbanned the testing of great apes.[30]
Conservation
The following table lists the estimated number of great ape individuals living outside zoos.
Below is a cladogram with extinct species.[39][40][41][failed verification] It is indicated approximately how many million years ago (Mya) the clades diverged into newer clades.[42]
Taxonomy ofHominoidea (emphasis on family Hominidae): After an initial separation from the main line by the Hylobatidae (gibbons) some 18 million years ago, the line ofPonginae broke away, leading to the orangutan; later, the Homininae split into the tribesHominini (led to humans and chimpanzees) andGorillini (led to gorillas).
In addition to the extant species and subspecies,archaeologists,paleontologists, andanthropologists have discovered and classified numerous extinct great ape species as below, based on the taxonomy shown.[44]
^"Great ape" is a common name rather than a taxonomic label, and there are differences in usage, even by the same author. The term may or may not include humans, as when Dawkins writes "Long before people thought in terms of evolution ... great apes were often confused with humans"[3][better source needed] and "gibbons are faithfully monogamous, unlike the great apes which are our closer relatives."[4][better source needed]
^Watson, E. E.; et al. (2001). "Homo genus: a review of the classification of humans and the great apes". In Tobias, P. V.; et al. (eds.).Humanity from African Naissance to Coming Millennia. Florence: Firenze Univ. Press. pp. 311–323.
^Schwartz, J.H. (1986). "Primate systematics and a classification of the order". In Swindler, Daris R.; Erwin, J. (eds.).Comparative Primate Biology. Vol. 1: Systematics, evolution, and anatomy. New York: Wiley-Liss. p. 1–41.ISBN978-0-471-62644-2.
^Wrangham, Richard (2007). "Chapter 12: The Cooking Enigma". In Charles Pasternak (ed.).What Makes Us Human?. Oxford: Oneworld Press.ISBN978-1-85168-519-6.
^An estimate of the number of wildorangutans in 2004:"Orangutan Action Plan 2007–2017"(PDF).Government of Indonesia. 2007.Archived(PDF) from the original on 1 September 2024.Pada IUCN Red List Edisi tahun 2002 orangutan sumatera dikategorikan Critically Endangered, artinya sudah sangat terancam kepunahan, sedangkan orangutan kalimantan dikategorikan Endangered atau langka.
^Malukiewicz, Joanna; Hepp, Crystal M.; Guschanski, Katerina; Stone, Anne C. (1 January 2017). "Phylogeny of the jacchus group of Callithrix marmosets based on complete mitochondrial genomes".American Journal of Physical Anthropology.162 (1):157–169.doi:10.1002/ajpa.23105.ISSN1096-8644.PMID27762445.Fig 2: "Divergence time estimates for the jacchus marmoset group based on the BEAST4 (Di Fiore et al., 2015) calibration scheme for alignment A.[...] Numbers at each node indicate the median divergence time estimate."
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