Difference between revisions of "Hominin" - New World Encyclopedia
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{{dablink|For an explanation of very similar terms see ''[[Hominid]]''.}} | {{dablink|For an explanation of very similar terms see ''[[Hominid]]''.}} | ||
| − | '''Hominin''' is any member of the [[primate]] tribe '''Hominini''', a [[taxonomy|classification]] that generally is considered to include only [[human]]s ([[Homo (genus)|genus ''Homo''), [[chimpanzee]]s (''Pan''), and their [[extinct]] ancestors. In recent classifications, Hominini is a tribe of the subfamily Homininae (humans, chimpanzees, [[gorilla]]s) of the family Hominidae (humans, chimpanzees, gorillas, and [[orangutan]]s). | + | '''Hominin''' is any member of the [[primate]] tribe '''Hominini''', a [[taxonomy|classification]] that generally is considered to include only [[human]]s ([[Homo (genus)|genus ''Homo'']]), [[chimpanzee]]s (''Pan''), and their [[extinct]] ancestors. In recent classifications, Hominini is a tribe of the subfamily Homininae (humans, chimpanzees, [[gorilla]]s) of the family Hominidae (humans, chimpanzees, gorillas, and [[orangutan]]s). |
| − | + | Unification aspects: chimpanzees and humans are placed together because of their remarkable genetic similarities. For example (from chimp article). But also note: (note differences) | |
| − | + | ==Overview of classification== | |
| − | + | Primate classification has undergone many revisions over the years, from the 1960s when humans were the only extant species in the family Hominidae until today, when it is common to place [[chimpanzee]]s, [[gorilla]]s, and [[orangutan]]s in Hominidae as well. (There are other taxonomic schemes, such as placing extant and extinct chimpanzees and gorillas in the family Panidae, orangutans in the historical group Pongidae, and humans in Hominidae). | |
| + | The creation of the taxon Hominini is the result of the current idea that the least similar species of a trichotomy should be separated from the other two. Thus, orangutans are separated into the subfamily Ponginae while the other great apes are placed in subfamily Homininae, and then the gorillas are separated into tribe Gorillini, while extant and extinct humans and chimpanzees are placed in tribe Hominini. | ||
| − | + | [[Image:Hominini.PNG|left|frame|[[Extant]] Hominoid family tree]] | |
| + | The exact criteria for membership in Homininae—the parent group of Hominini—are not clear, but the subfamily generally includes those [[species]] which share more than 97% of their [[DNA]] with the modern human [[genome]], and exhibit a capacity for [[language]] or for simple [[culture]]s beyond the family or band. | ||
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| + | Discuss chimpanzess and humans, and their similariteis, and the creation of Hominini: | ||
In the proposal of Mann and Weiss (1996),<ref name=Mann>{{cite journal | author = Mann, Alan and Mark Weiss | year = 1996 | title = Hominoid Phylogeny and Taxonomy: a consideration of the molecular and Fossil Evidence in an Historical Perspective | journal = Molecular Phylogenetics and Evolution | volume = 5 | issue = 1 | pages = 169-181}}</ref> the tribe ''Hominini'' includes ''Pan'' as well as ''Homo'' as separate subtribes. ''Homo'' (and, by inference, all bipedal apes) is by itself only in the subtribe [[Hominina]], while ''Pan'' is in the [[Panina (subtribe)|Panina]] subtribe. | In the proposal of Mann and Weiss (1996),<ref name=Mann>{{cite journal | author = Mann, Alan and Mark Weiss | year = 1996 | title = Hominoid Phylogeny and Taxonomy: a consideration of the molecular and Fossil Evidence in an Historical Perspective | journal = Molecular Phylogenetics and Evolution | volume = 5 | issue = 1 | pages = 169-181}}</ref> the tribe ''Hominini'' includes ''Pan'' as well as ''Homo'' as separate subtribes. ''Homo'' (and, by inference, all bipedal apes) is by itself only in the subtribe [[Hominina]], while ''Pan'' is in the [[Panina (subtribe)|Panina]] subtribe. | ||
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| − | + | ==Pan/Homo split== | |
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| + | Next two paragraphs do Pan/Homo split: (combine) | ||
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| + | Through [[DNA]] comparison, scientists believe they have determined that the ''Pan/Homo'' split happened about 5 to 7 million years ago.<ref name=split> {{cite web | url = http://www.physorg.com/news9211.html | title = Scientists narrow time limits for human, chimp split | accessdate = 2005-12-21 | data = 2005-12-20 | work = [http://www.physorg.com PhysOrg.com]}}</ref> It is interesting to note that no fossil species on the ''Pan'' side of the split have been determined; all of the extinct genera listed to the right are ancestral to ''Homo'', or are offshoots of such. However, both ''[[Orrorin]]'' and ''[[Sahelanthropus]]'' existed around the time of the split, and so may be ancestral to both humans and chimpanzees. | ||
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| + | It is generally believed that the ''Pan/Homo'' split occurred about 6.5–7.4 million years ago, but the [[molecular clock]] (a method of calculating evolution based on the speed at which genes mutate) suggests the genera split 5.4–6.3 million years ago. Previous studies looked at average genetic differences between human and chimp. The new study compares the ages of key sequences of genes of modern humans and modern chimps. Some sequences are younger than others, indicating that chimps and humans gradually split apart over a period of 4 million years. The youngest human chromosome is the X sex chromosome which is about 1.2 million years more recent than the 22 autosomes. The X chromosome is known to be vulnerable to selective pressure. Its age suggests there was an initial split between the two species, followed by gradual divergence and interbreeding that resulted in younger genes, and then a final separation. | ||
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In [[2002]], a 6–7 million year old [[fossil]] [[skull]] nicknamed "Toumaï" by its discoverers, and formally classified as ''[[Sahelanthropus tchadensis]]'', was discovered in [[Chad]] and is possibly the earliest hominid [[fossil]] ever found. In addition to its age, Toumaï, unlike the 3–4 million year younger [[gracile australopithecine]] dubbed "[[Australopithecus afarensis|Lucy]]", has a relatively flat face without the prominent snout seen on other pre-''[[Homo (genus)|Homo]]'' hominids. Some researchers have made the suggestion that this previously unknown species may in fact be a direct ancestor of modern humans (or at least closely related to a direct ancestor). Others contend that one fossil is not enough to make such a claim because it would overturn the conclusions of over 100 years of [[anthropology|anthropological]] study. A report on this finding was published in the journal ''[[Nature (journal)|Nature]]'' on [[July 11]], [[2002]]. While some scientists claim that it is merely the skull of a female gorilla, others have called it the most important hominin fossil since ''Australopithecus''. | In [[2002]], a 6–7 million year old [[fossil]] [[skull]] nicknamed "Toumaï" by its discoverers, and formally classified as ''[[Sahelanthropus tchadensis]]'', was discovered in [[Chad]] and is possibly the earliest hominid [[fossil]] ever found. In addition to its age, Toumaï, unlike the 3–4 million year younger [[gracile australopithecine]] dubbed "[[Australopithecus afarensis|Lucy]]", has a relatively flat face without the prominent snout seen on other pre-''[[Homo (genus)|Homo]]'' hominids. Some researchers have made the suggestion that this previously unknown species may in fact be a direct ancestor of modern humans (or at least closely related to a direct ancestor). Others contend that one fossil is not enough to make such a claim because it would overturn the conclusions of over 100 years of [[anthropology|anthropological]] study. A report on this finding was published in the journal ''[[Nature (journal)|Nature]]'' on [[July 11]], [[2002]]. While some scientists claim that it is merely the skull of a female gorilla, others have called it the most important hominin fossil since ''Australopithecus''. | ||
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In addition to the Tourmai fossil, some experts use evidence from the genome to argue that the species associated with the chimpanzees and proto-humans split interbred over a long period of time, swapping genes, before making a final separation. A paper, whose authors include [[David Reich]] and [[Eric Lander]] (Harvard and the Massachusetts Institute of Technology (MIT)), was published in journal ''[[Nature (journal)|Nature]]'' in May 2006. | In addition to the Tourmai fossil, some experts use evidence from the genome to argue that the species associated with the chimpanzees and proto-humans split interbred over a long period of time, swapping genes, before making a final separation. A paper, whose authors include [[David Reich]] and [[Eric Lander]] (Harvard and the Massachusetts Institute of Technology (MIT)), was published in journal ''[[Nature (journal)|Nature]]'' in May 2006. | ||
| − | + | ==theory of mind== | |
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| + | The [[theory of mind]] including such faculties as mental state attribution, empathy and even empathetic deception is a controversial criterion distinguishing the adult human alone among the hominids. Humans acquire this capacity at about four and a half years of age, whereas it has neither been proven nor disproven that gorillas and chimpanzees develop a theory of mind.<ref>{{cite journal | author = Heyes, C. M. | year = 1998 | title = THEORY OF MIND IN NONHUMAN PRIMATES | journal = Behavioral and Brain Sciences | id = bbs00000546 | url = http://www.bbsonline.org/documents/a/00/00/05/46/index.html}}</ref> This is also the case for some [[new world monkey]]s outside the family of great apes, as, for example, the [[Capuchin_monkey#Theory_of_mind|capuchin monkeys]]. | ||
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| + | However, without the ability to test whether early members of the Homininae (such as ''[[Homo erectus]]'', ''[[Homo neanderthalensis]]'', or even the australopithecines) had a theory of mind, it is difficult to ignore similarities seen in their living cousins. Despite an apparent lack of real culture and significant physiological and psychological differences, some say that the orangutan may also satisfy these criteria. These scientific debates take on political significance for advocates of [[Great Ape personhood]]. | ||
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Subtribe Panina Subtribe Hominina
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- For an explanation of very similar terms see Hominid.
Hominin is any member of the primate tribe Hominini, a classification that generally is considered to include only humans (genus Homo), chimpanzees (Pan), and their extinct ancestors. In recent classifications, Hominini is a tribe of the subfamily Homininae (humans, chimpanzees, gorillas) of the family Hominidae (humans, chimpanzees, gorillas, and orangutans).
Unification aspects: chimpanzees and humans are placed together because of their remarkable genetic similarities. For example (from chimp article). But also note: (note differences)
Overview of classification
Primate classification has undergone many revisions over the years, from the 1960s when humans were the only extant species in the family Hominidae until today, when it is common to place chimpanzees, gorillas, and orangutans in Hominidae as well. (There are other taxonomic schemes, such as placing extant and extinct chimpanzees and gorillas in the family Panidae, orangutans in the historical group Pongidae, and humans in Hominidae).
The creation of the taxon Hominini is the result of the current idea that the least similar species of a trichotomy should be separated from the other two. Thus, orangutans are separated into the subfamily Ponginae while the other great apes are placed in subfamily Homininae, and then the gorillas are separated into tribe Gorillini, while extant and extinct humans and chimpanzees are placed in tribe Hominini.
The exact criteria for membership in Homininae—the parent group of Hominini—are not clear, but the subfamily generally includes those species which share more than 97% of their DNA with the modern human genome, and exhibit a capacity for language or for simple cultures beyond the family or band.
Discuss chimpanzess and humans, and their similariteis, and the creation of Hominini:
In the proposal of Mann and Weiss (1996),[1] the tribe Hominini includes Pan as well as Homo as separate subtribes. Homo (and, by inference, all bipedal apes) is by itself only in the subtribe Hominina, while Pan is in the Panina subtribe.
Pan/Homo split
Next two paragraphs do Pan/Homo split: (combine)
Through DNA comparison, scientists believe they have determined that the Pan/Homo split happened about 5 to 7 million years ago.[2] It is interesting to note that no fossil species on the Pan side of the split have been determined; all of the extinct genera listed to the right are ancestral to Homo, or are offshoots of such. However, both Orrorin and Sahelanthropus existed around the time of the split, and so may be ancestral to both humans and chimpanzees.
It is generally believed that the Pan/Homo split occurred about 6.5–7.4 million years ago, but the molecular clock (a method of calculating evolution based on the speed at which genes mutate) suggests the genera split 5.4–6.3 million years ago. Previous studies looked at average genetic differences between human and chimp. The new study compares the ages of key sequences of genes of modern humans and modern chimps. Some sequences are younger than others, indicating that chimps and humans gradually split apart over a period of 4 million years. The youngest human chromosome is the X sex chromosome which is about 1.2 million years more recent than the 22 autosomes. The X chromosome is known to be vulnerable to selective pressure. Its age suggests there was an initial split between the two species, followed by gradual divergence and interbreeding that resulted in younger genes, and then a final separation.
In 2002, a 6–7 million year old fossil skull nicknamed "Toumaï" by its discoverers, and formally classified as Sahelanthropus tchadensis, was discovered in Chad and is possibly the earliest hominid fossil ever found. In addition to its age, Toumaï, unlike the 3–4 million year younger gracile australopithecine dubbed "Lucy", has a relatively flat face without the prominent snout seen on other pre-Homo hominids. Some researchers have made the suggestion that this previously unknown species may in fact be a direct ancestor of modern humans (or at least closely related to a direct ancestor). Others contend that one fossil is not enough to make such a claim because it would overturn the conclusions of over 100 years of anthropological study. A report on this finding was published in the journal Nature on July 11, 2002. While some scientists claim that it is merely the skull of a female gorilla, others have called it the most important hominin fossil since Australopithecus.
In addition to the Tourmai fossil, some experts use evidence from the genome to argue that the species associated with the chimpanzees and proto-humans split interbred over a long period of time, swapping genes, before making a final separation. A paper, whose authors include David Reich and Eric Lander (Harvard and the Massachusetts Institute of Technology (MIT)), was published in journal Nature in May 2006.
theory of mind
The theory of mind including such faculties as mental state attribution, empathy and even empathetic deception is a controversial criterion distinguishing the adult human alone among the hominids. Humans acquire this capacity at about four and a half years of age, whereas it has neither been proven nor disproven that gorillas and chimpanzees develop a theory of mind.[3] This is also the case for some new world monkeys outside the family of great apes, as, for example, the capuchin monkeys.
However, without the ability to test whether early members of the Homininae (such as Homo erectus, Homo neanderthalensis, or even the australopithecines) had a theory of mind, it is difficult to ignore similarities seen in their living cousins. Despite an apparent lack of real culture and significant physiological and psychological differences, some say that the orangutan may also satisfy these criteria. These scientific debates take on political significance for advocates of Great Ape personhood.
See also
ReferencesISBN links support NWE through referral fees
- ↑ Mann, Alan and Mark Weiss (1996). Hominoid Phylogeny and Taxonomy: a consideration of the molecular and Fossil Evidence in an Historical Perspective. Molecular Phylogenetics and Evolution 5 (1): 169-181.
- ↑ Scientists narrow time limits for human, chimp split. PhysOrg.com. Retrieved 2005-12-21.
- ↑ Heyes, C. M. (1998). THEORY OF MIND IN NONHUMAN PRIMATES. Behavioral and Brain Sciences. bbs00000546.
Sahelanthropus tchadensis • Orrorin tugenensis • Ardipithecus
Australopithecus: A. anamensis • A. afarensis • A. bahrelghazali • A. africanus • A. garhi
Paranthropus: P. aethiopicus • P. boisei • P. robustus
Kenyanthropus platyops
Homo: H. habilis • H. rudolfensis • H. georgicus • H. ergaster • H. erectus (H. e. lantianensis • H. e. palaeojavanicus • H. e. pekinensis • H. e. soloensis) • H. cepranensis • H. antecessor • H. heidelbergensis • H. neanderthalensis • H. rhodesiensis • H. floresiensis • Homo sapiens (H. s. idaltu • H. s. sapiens)
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