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Title: Homininae  
Author: World Heritage Encyclopedia
Language: English
Subject: Chimpanzee, Sahelanthropus, Bipedalism, Human evolution, Chimpanzee–human last common ancestor
Publisher: World Heritage Encyclopedia


same is likely true for gorillas.

Evolutionary tree of the Hominoidea : after an initial separation from the main line of Hylobatidae (current gibbons), some 18 million years ago, the line of Ponginae broke away, leading to the current orangutan, while the Homininae split later in Gorillini and Hominini.

Taxonomic classification



Evolution of bipedalism

Recent studies of Ardipithecus ramidus (4.4 million years old) and Orrorin tugenensis (6 million years old) suggest some degree of bipedalism. Australopithecus and early Paranthropus may have been bipedal. Very early hominins such as Ardipithecus ramidus may have possessed an arboreal type of bipedalism.[10] and towards efficient walking and running in modern humans.

Brain size evolution

There has been a gradual increase in brain volume (brain size) as the ancestors of modern humans progressed along the timeline of human evolution, starting from about 600 cm3 in Homo habilis up to 1500 cm3 in Homo sapiens neanderthalensis. However, modern Homo sapiens have a brain volume slightly smaller (1250 cm3) than Neanderthals, women have a brain slightly smaller than men and the Flores hominids (Homo floresiensis), nicknamed hobbits, had a cranial capacity of about 380 cm3 (considered small for a chimpanzee), about a third of the Homo erectus average. It is proposed that they evolved from H. erectus as a case of insular dwarfism. In spite of their smaller brain, there is evidence that H. floresiensis used fire and made stone tools at least as sophisticated as those of their proposed ancestors H. erectus.[11] In this case, it seems that for intelligence, the structure of the brain is more important than its size.[12]

Evolution of family structure and sexuality

Sexuality is related to family structure and partly shapes it. The involvement of fathers in education is quite unique to humans, at least when compared to other Homininae. Concealed ovulation and menopause in women both also occur in a few other primates however, but are uncommon in other species. Testis and penis size seems to be related to family structure: monogamy or promiscuity, or harem, in humans, chimpanzees or gorillas, respectively.[13][14] The levels of sexual dimorphism are generally seen as a marker of sexual selection. Studies have suggested that the earliest hominins were dimorphic and that this lessened over the course of the evolution of the genus Homo, correlating with humans becoming more monogamous, whereas gorillas, who live in harems, show a large degree of sexual dimorphism. Concealed (or "hidden") ovulation means that the phase of fertility is not detectable in women, whereas chimpanzees advertise ovulation via an obvious swelling of the genitals. Women can be partly aware of their ovulation along the menstrual phases, but men are essentially unable to detect ovulation in women. Most primates have semi-concealed ovulation, thus one can think that the common ancestor had semi-concealed ovulation, that was inherited by gorillas, and that later evolved in concealed ovulation in humans and advertised ovulation in chimpanzees. Menopause also occurs in rhesus monkeys, and possibly in chimpanzees, but does not in gorillas and is quite uncommon in other primates (and other mammal groups).[14]

See also


  1. ^ A hominin is a member of the tribe Hominini, a hominine is a member of the subfamily Homininae, a hominid is a member of the family Hominidae, and a hominoid is a member of the superfamily Hominoidea.


  1. ^
  2. ^ Goodman, M. (1974). "Biochemical Evidence on Hominid Phylogeny". Annual Review of Anthropology 3: 203–228.  
  3. ^ Goodman M., Tagle D.A., Fitch D.H., Bailey W., Czelusniak J., Koop B.F., Benson P., Slightom J.L. (1990). "Primate evolution at the DNA level and a classification of hominoids". Journal of Molecular Evolution 30 (3): 260–6.  
  4. ^ McBrearty S, Jablonski N (2005). "First fossil chimpanzee". Nature 437 (7055): 105–8.  
  5. ^ Haaramo, Mikko (2005-01-14). "Hominoidea". Mikko's Phylogeny Archive. 
  6. ^ Haaramo, Mikko (2007-11-10). "Hominidae". Mikko's Phylogeny Archive. 
  7. ^ Asfaw 1999 (ape)"Praeanthropus garhi". Paleobiology Database. Fossilworks. 
  8. ^ Barras, Colin (2012-03-14). "Chinese human fossils unlike any known species". New Scientist. Retrieved 2012-03-15. 
  9. ^ "Pongo pygmaeus"Orangutan . Animals.  
  10. ^ Kivell TL, Schmitt D (August 2009). "Independent evolution of knuckle-walking in African apes shows that humans did not evolve from a knuckle-walking ancestor". Proc. Natl. Acad. Sci. U.S.A. 106 (34): 14241–6.  
  11. ^ Brown P, Sutikna T, Morwood MJ, et al. (2004). "A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia". Nature 431 (7012): 1055–61.  
  12. ^ Davidson, I. (2007). "Homo floresiensis"As large as you need and as small as you can—implications of the brain size of . In Schalley, A.C.; Khlentzos, D. Mental States: Evolution, function, nature; 2. Language and cognitive structure. Studies in language companion. 92–93. John Benjamins. pp. 35–42.  
  13. ^  
  14. ^ a b


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