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Homo
Homo
Pan † Australopithecina

* † Australopithecus
Australopithecus
* † Kenyanthropus * † Paranthropus
Paranthropus
* † Ardipithecus

Sahelanthropus
Sahelanthropus
Orrorin
Orrorin
?† Graecopithecus († =extinct =fossil)

The HOMININI is a taxonomical tribe of the subfamily Homininae ; it comprises three subtribes: Hominina , with its one genus Homo
Homo
; Australopithecina , comprising at least three extinct (or, fossil) genera (see inset at bottom right); and Panina , with its one genus Pan , the chimpanzees (see the evolutionary tree below). Members of the human clade , that is, the subtribe Hominina, include only the genus Homo; it is the "human" branch as depicted in an evolutionary tree chart (see below). Over the past several decades, a broad community of scientists and scholars have adopted the term "HOMININS" to emphasize the history of proto-humans speciating from the stem chimpanzees—which process began about eight million years ago; see chimpanzee-human last common ancestor (CHLCA) . Thus, the genus Homo and those species of the australopithecines that arose after the split from the last common ancestor with chimpanzees are called "hominins". Not all hominins are directly related to the emergence of early Homo.

Researchers proposed the taxon Hominini on the basis that the least similar species of a trichotomy should be separated from the other two. The common chimpanzee and the bonobo of the genus Pan are the closest living evolutionary relatives to humans, sharing a common ancestor with humans about four to seven million years ago. Most DNA studies find that humans and Pan are 99% identical, but one study found only 94% commonality, with some of the difference occurring in noncoding DNA
DNA
.

CONTENTS

* 1 Taxonomy

* 1.1 Complex speciation and hybridization * 1.2 Cladogram of the superfamily Hominoidea

* 2 Pan– Homo
Homo
divergence * 3 See also * 4 References * 5 External links

TAXONOMY

The human clade, the subtribe Hominina, contains only Homo; it is the "human" branch as depicted in a tree of life or in an evolutionary tree chart (see below). It is a branch of the family Hominidae
Hominidae
—the hominids—one of the families of the order primates known as the "family of great apes ". One community of scientists and scholars emphasizes the long, drawn-out speciation of proto-humans from stem chimpanzees—which process started sometime after about eight million years ago (Mya) and may have taken until four Mya to completion (see Complex ... hybridization ). This community applies the term HOMININ to all Homo
Homo
species and those species of australopithecines and other genera that arose after the split from the line to chimpanzees (see cladogram below); that is, they distinguish fossil members on the human side of the split, as hominins, from those on the chimpanzee side, as not hominins.

It is likely that the australopithecines gave rise to the earliest Homo
Homo
genera. The earliest hominins also produced lines, whether of australopithecines or other genera, that arose after speciating from the line to chimpanzees but went extinct without developing into Homo; thus, not all hominins are ancestral to the emergence of early Homo. (See "Genera", classification infobox.)

All the listed fossil genera currently are being, or have been, evaluated for: 1) probability of being ancestral to Homo, and 2) whether they are more closely related to Homo
Homo
than to any other living primate—two traits that could identify them as hominins. Some, including Paranthropus
Paranthropus
, Kenyanthropus , Ardipithecus , and Australopithecus
Australopithecus
, are broadly thought to be ancestral and closely related to Homo; others, especially earlier genera, including Sahelanthropus
Sahelanthropus
(and perhaps Orrorin
Orrorin
), are supported by one community of scientists/ scholars but doubted by another. Evolutionary tree chart emphasizing the family Hominidae
Hominidae
and the tribe Hominini. After diverging from the line to Ponginae the subfamily Homininae split into the tribes Hominini and Gorillini . The Hominini speciated further, splitting the line to Homo
Homo
from the line to Pan. Currently, tribe Hominini designates three subtribes: Hominina , containing genus Homo; Panina , containing genus Pan; and the extinct Australopithecina , the australopithecines—several genera that arose on the 'human side' after the split from the line to the chimpanzees. (The subtribes, including the genera Australopithecina, are not labelled on this chart.)

Both Sahelanthropus
Sahelanthropus
and Orrorin
Orrorin
existed during the estimated duration of the (ancestral) chimpanzee-human speciation events, within the range of eight to four million years ago (Mya); see CHLCA . So one or both of these specimens may yet prove to be "hybrid" (see Complex ..hybridization ), and thereby ancestral to both Pan and Homo—or to Pan instead of Homo. Very few fossil specimens have been found on the Pan 'side' of the split from the common ancestral line. News of the first fossil chimpanzee, found in Kenya, was published in 2005. However, it is dated to very recent times—between 545 and 284 thousand years ago radiometric (kyr).

In the proposal of Mann and Weiss (1996), the tribe Hominini includes Pan as well as Homo, but within separate subtribes. Homo
Homo
and (by inference) all bipedal apes are referred to the subtribe Hominina , while Pan is assigned to the subtribe Panina . Wood (2010) discusses the different views of this taxonomy.

COMPLEX SPECIATION AND HYBRIDIZATION

Regarding the speciation of proto-humans from stem chimpanzees there is evidence that a complex speciation -hybridization process—rather than a clean split—occurred between the two lineages. Such a complex process greatly confuses estimating the actual age of the final Homo-Pan divergence, or split. Different chromosomes appear to have split at different times, over possibly as much as a four-million-year period; this indicates a long and drawn out speciation process with broad-scale hybridization activity occurring between the two emerging lineages as late as the period 6.3 to 5.4 Mya, according to Patterson et al. (2006), This research group noted that one (hypothetical) late hybridization period was based in particular on the similarity of X chromosomes in the proto-humans and stem chimpanzees, suggesting the final divergence even as recent as 4 Mya. Wakeley (2008) rejected these hypotheses; he suggested alternative explanations, including selection pressure on the X chromosome
X chromosome
in the ancestral populations prior to the chimpanzee–human last common ancestor (CHLCA).

CLADOGRAM OF THE SUPERFAMILY HOMINOIDEA

This cladogram shows the clade of superfamily Hominoidea and its descendent clades; it features the hominids, which is the family Hominidae. The hominids comprise the orangutans, gorillas, and the clade of the tribe Hominini—which groups the subtribe Panina (chimpanzees), the extinct subtribe Australopithecina (australopithicenes), and the subtribe Hominina (humans).

Hominoidea (≈20 to 15 Mya)

Hylobatidae (gibbons)

Hominidae
Hominidae
(≈14 Mya)

Ponginae (orangutans)

Homininae

Gorillini (gorillas)

Hominini

Panina (chimpanzees)

*

Australopithecina (australopithecines )

Hominina (humans)

The scientist/ scholar community has not reached a consensus regarding a taxon for the (probable) ancestral stem between the subtribes Hominina and Australopithecina—hence the blank space (*) after the tribe-label "Hominini". However, the community has informally adopted a name to refer to humans and their closest biological relatives. These comprise the several Homo
Homo
genera—only one of which is not extinct—plus those australopithecines that rose after the splitting of the lineage of chimpanzees from the last common ancestor(s) (LCA). These humans and australopithecines collectively are called HOMININS.

Morphological and geological/ radiometric analyses indicate that ancestral hominids, that is, the most recent common ancestors (MRCA, the equivalent of LCA) of the subfamilies Homininae and Ponginae, lived until at least about 14 million years ago (Mya), prior to the ancestors of orangutans speciating from the common ancestors. Previously, the common ancestors of hominids had speciated from the superfamily Hominoidae between 20 and 15 million years ago. Recent molecular analyses have refined some paleo-chronological dates for the emergence of specific clades.

PAN–HOMO DIVERGENCE

It has been suggested that Chimpanzee–human last common ancestor be merged into this article. (Discuss ) Proposed since December 2015.

SEE ALSO

* Dawn of Humanity (2015 PBS film) * History of hominoid taxonomy * Human
Human
evolution * List of human evolution fossils (with images)

REFERENCES

* ^ Fuss, J; Spassov, N; Begun, DR; Böhme, M (2017). "Potential hominin affinities of Graecopithecus from the Late Miocene of Europe". PLoS ONE. 12 (5). * ^ "Chimps and Humans Very Similar at the DNA
DNA
Level". News.mongabay.com. Retrieved 2009-06-06. * ^ Mary-Claire King (1973) Protein polymorphisms in chimpanzee and human evolution, Doctoral dissertation, University of California, Berkeley. * ^ Wong, Kate (1 September 2014). "Tiny Genetic Differences between Humans and Other Primates
Primates
Pervade the Genome". Scientific American . * ^ Minkel JR (2006-12-19). "Humans and Chimps: Close But Not That Close". Scientific American. * ^ Bradley, B. J. (2006). "Reconstructing Phylogenies and Phenotypes: A Molecular View of Human
Human
Evolution" . Journal of Anatomy. 212 (4): 337–353. PMC 2409108  . PMID 18380860 . doi :10.1111/j.1469-7580.2007.00840.x . * ^ Wood and Richmond.; Richmond, BG (2000). " Human
Human
evolution: taxonomy and paleobiology" . Journal of Anatomy. 197 (Pt 1): 19–60. PMC 1468107  . PMID 10999270 . doi :10.1046/j.1469-7580.2000.19710019.x . Thus human evolution is the study of the lineage, or clade, comprising species more closely related to modern humans than to chimpanzees. Its stem species is the so-called ‘common hominin ancestor’, and its only extant member is Homo
Homo
sapiens. This clade contains all the species more closely-related to modern humans than to any other living primate. Until recently, these species were all subsumed into a family, Hominidae, but this group is now more usually recognised as a tribe, the Hominini. * ^ A B Coyne, Jerry A. (2009) Why Evolution
Evolution
Is True, pp.197-208, 244, 248. ISBN 978-0-670-02053-9 (hc), ISBN 978-0-14-311664-6 (pbk). Penguin Books Ltd, London. "Anthropologists apply the term hominin to all the species on the "human" side of our family tree after it split from the branch that became modern chimps." (p.197) * ^ Coyne, Jerry A. (2009) Why Evolution
Evolution
Is True, pp.202-204. ISBN 978-0-670-02053-9 (hc), ISBN 978-0-14-311664-6 (pbk). Penguin Books Ltd, London. "After A. afarensis, the fossil record shows a confusing melange of gracile australopithecine species lasting up to about two million years ago. … he late australopithecines, already bipedal, were beginning to show changes in teeth, skull, and brain that presage modern humans. It is very likely that the lineage that gave rise to modern humans included at least one of these species." * ^ Cameron, D. W. (2003). "Early hominin speciation at the Plio/Pleistocene transition.". HOMO - Journal of Comparative Human Biology. 54 (1): 1–28. PMID 12968420 . doi :10.1078/0018-442x-00057 . * ^ A B http://australianmuseum.net.au/Hominid-and-hominin-whats-the-difference * ^ Potts, Richard and Sloan, Christopher. “What Does It Mean to Be Human?”, pp. 31-42. ISBN 978-1-4262-0606-1 . National Geographic Society, Washington. * ^ Brunet, Michel; Guy, F; Pilbeam, D; MacKaye, H. T.; Likius, A; Ahounta, D; Beauvilain, A; Blondel, C; Bocherens, H; Boisserie, JR; De Bonis, L; Coppens, Y; Dejax, J; Denys, C; Duringer, P; Eisenmann, V; Fanone, G; Fronty, P; Geraads, D; Lehmann, T; Lihoreau, F; Louchart, A; Mahamat, A; Merceron, G; Mouchelin, G; Otero, O; Pelaez Campomanes, P; Ponce De Leon, M; Rage, J. C.; et al. (July 2002), "A new hominid from the Upper Miocene of Chad, Central Africa", Nature, 418 (6894): 145–151, PMID 12110880 , doi :10.1038/nature00879 , Sahelanthropus is the oldest and most primitive known member of the hominid clade, close to the divergence of hominids and chimpanzees. * ^ Wolpoff, Milford; Senut, Brigitte; Pickford, Martin; Hawks, John (October 2002), " Sahelanthropus
Sahelanthropus
or 'Sahelpithecus'?", Nature, 419 (6907): 581–582, Bibcode :2002Natur.419..581W, PMID 12374970 , doi :10.1038/419581a , Sahelanthropus
Sahelanthropus
tchadensis is an enigmatic new Miocene species, whose characteristics are a mix of those of apes and Homo
Homo
erectus and which has been proclaimed by Brunet et al. to be the earliest hominid. However, we believe that features of the dentition, face and cranial base that are said to define unique links between this Toumaï specimen and the hominid clade are either not diagnostic or are consequences of biomechanical adaptations. To represent a valid clade, hominids must share unique defining features, and Sahelanthropus
Sahelanthropus
does not appear to have been an obligate biped. * ^ McBrearty, Sally; Nina G. Jablonski (2005). "First fossil chimpanzee". Nature. 437 (7055): 105–108. Bibcode :2005Natur.437..105M. PMID 16136135 . doi :10.1038/nature04008 . * ^ Mann, Alan; 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. PMID 8673284 . doi :10.1006/mpev.1996.0011 . * ^ B. Wood (2010). "Reconstructing human evolution: Achievements, challenges, and opportunities" . Proceedings of the National Academy of Sciences. 107: 8902–8909. Bibcode :2010PNAS..107.8902W. PMC 3024019  . PMID 20445105 . doi :10.1073/pnas.1001649107 . * ^ Patterson N, Richter DJ, Gnerre S, Lander ES, Reich D; Richter; Gnerre; Lander; Reich (June 2006). "Genetic evidence for complex speciation of humans and chimpanzees". Nature. 441 (7097): 1103–8. Bibcode :2006Natur.441.1103P. PMID 16710306 . doi :10.1038/nature04789 . CS1 maint: Multiple names: authors list (link ) * ^ Wakeley J (March 2008). "Complex speciation of humans and chimpanzees". Nature. 452 (7184): E3–4; discussion E4. Bibcode :2008Natur.452....3W. PMID 18337768 . doi :10.1038/nature06805 . "Patterson et al. suggest that the apparently short divergence time between humans and chimpanzees on the X chromosome
X chromosome
is explained by a massive interspecific hybridization event in the ancestry of these two species. However, Patterson et al. do not statistically test their own null model of simple speciation before concluding that speciation was complex, and—even if the null model could be rejected—they do not consider other explanations of a short divergence time on the X chromosome. These include natural selection on the X chromosome
X chromosome
in the common ancestor of humans and chimpanzees, changes in the ratio of male-to-female mutation rates over time, and less extreme versions of divergence with gene flow. I therefore believe that their claim of hybridization is unwarranted." * ^ Andrew Hill; Steven Ward (1988). "Origin of the Hominidae: The Record of African Large Hominoid Evolution
Evolution
Between 14 My and 4 My". Yearbook of Physical Anthropology. 31 (59): 49–83. doi :10.1002/ajpa.1330310505 . * ^ A B Dawkins R (2004) The Ancestor's Tale. * ^ "Query: Hominidae/Hylobatidae". Time Tree. 2009. Retrieved December 2010. Check date values in: access-date= (help )

EXTERNAL LINKS

Wikispecies
Wikispecies
has information related to: HOMININI

* Human
Human
Timeline (Interactive)

.