a201-11f-23-WorldFullOfPlioPleistoceneHominins

And with kenyanthropus s more vertical human like

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- and with Kenyanthropus ’s more vertical, human-like face - this would make Kenyanthropus a logical ancestor for humans - leaving australopithecines as a side branch that specialized on seeds, then went extinct - Kenyanthropus could be the maker of the stone tool cutmarks from Dikka at 3.4 mya - the hypothetical descendents of Kenyanthropus could be the makers of the stone tool cutmarks found with A. garhi around 2.5 mya, rather than the small-brained A. garhi - only more fossils will resolve this - The phylogeny is uncertain - many different phylogenies are possible, none clearly the best - were our ancestors… - australopithecines? - Kenyanthropus ? - maybe Kenyanthropus via A. rudolfensis , but not the earlier australopithecines?
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Intro to Biological Anthro F 2011 / Owen: World full of Plio-pleistocene hominins p. 5 - was Sahelanthropus in our lineage, or did it lead to gorillas, or did it go extinct? - Overall pattern of hominin evolution - 7-5 mya, maybe slightly earlier: the hominin (bipedal) lineage split from the lineage leading to chimps - bipedalism evolved during this time; evidence is still sketchy - 4.0-2.9 mya: good evidence about A. afarensis - 3.5 mya: Kenyanthropus , a second hominin contemporary with A. afarensis - the first stone tool cutmarks appeared around this time - 3.0-1.0 mya: lots of Plio-pleistocene hominins - Paranthropus (at least 3 species, up to 2 at one time) - extreme chewing adaptations - Australopithecus (at least 5 species, up to 2 or 3 at one time) - moderately heavy chewing adaptation - plus possible descendents of Kenyanthropus - least exaggerated chewing - plus the first species of the genus Homo around 1.8 mya - we’ll look at these later - Whatever the phylogenetic relationships, the current evidence suggests that our lineage probably evolved from a Plio-pleistocene hominin generally similar to the australopithecines discussed here, that: - was bipedal - thus terrestrial - but continued to spend a fair amount of time in the trees - had grinding molars and reduced canines - good for a wide range of foods - had considerable sexual dimorphism in body size - so it probably lived in multi-female, multi-male groups - with lots of male-male competition - unless the reduced sexual dimorphism of canines in Ardipithecus is a clue to the contrary - had a brain comparable in size to a chimp’s, or some a bit bigger - except the late A. rudolfensis , considerably larger - had short, rapid juvenile development, like a chimp’s - probably made - expedient tools of plant material, bone, etc. - simple stone tools - evidently ate some meat, given the cutmarks on animal bones - maybe hunted, similarly to chimps
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