origins of humanity - midterm 3 study guide

origins of humanity - midterm 3 study guide - Midterm#3...

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Midterm #3 Study Guide Chapters 12, 13, 14, 15, 16, 17, 18 Chapter 12: Early Hominids Hominids- early hominids beginning around 7 million years ago -diverged from last common ancestor (chimp)- 6 million years ago -fundamental adaptation- bipedality -possesses human or intermediate condition of skull and dentition -face = relatively prognathic ( facial prognathism - the degree to which the face projects in front of the braincase) - CP3, or sectorial premolar complex - combination of canine and first premolar teeth that form a self-sharpening apparatus -mammals possess heterodont dentition- tooth array in which different teeth have different forms and functions -vs. homodont dentition- having teeth that are uniform in form, shape, function; ex: lizards, fish -thickness of enamel: human enamel is thick -apes/humans also differ in brain size, cranial proportions, and cranial cresting -deemphasis of masticatory (chewing) system -emphasis on brain size and intelligence -early hominids- loss of cranial crest more rounded braincase -bony ridges on skull to which muscles attach -shift to bipedality: response to major climatory changes in equatorial Africa / late Miocene anatomical changes in pelvis, spinal column, etc. - Sahelanthropus Tchadensis - see note card - Orrorin Tugenesis - Ardipithecus Ramidus - see note card Australopithecines - eastern, southern, central Africa -4.2-1.0 million years ago -bipedal, small-bodied apes, small brained, moderately prognathic faces - Australopithecus Anamensis - see note card - Australopithecus Afarensis - see note card - Australopithecus Bahghazali - Kenyanthropus Platyops - see note card - Australopithecus Garhi - see note card - Australopithecus Africanus - see note card The Robust Australopithecines - first found in 1938 by South Africa by Robert Broom -East African species- 1959 in Olduvai Gorge, Tanzania by Mary Leakey -cranial features as an adaptation to hard object feeding - chewing tough, hard-to-break food items such as nuts or fibrous vegetation - muscles of mastication - maximized in size -temporalis is englarged and moved forward; anterior sagittal crest for its attachment -extreme postorbital constriction - to accommodate its large size
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-the pinching-in of the cranium just behind the orbits where the temporalis muscle sits -little constriction- large brain, small muscle -great constriction- large muscle** (robust australopithecines) -flaring of the zygomatic arches - laterally to accommodate the bigger muscle -bony arch formed by the zygomatic (cheek) bone and the temporal bone of the skull -large and deep mandible; face is tall - Australopithecus aethipicus - see note card - A. boisei - see note card - A. robustus - see note card Cohabitation- in some cases, 2 species occurred contemporaneously in the same habitat -natural selection avoidance of feeding competition -possibly A. africanus and A. robustus in southern Africa -possibly A. boisei (robust) and early genus Homo (gracile) in eastern Africa -possibly A. garhi and A. aethiopicus in eastern Africa
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origins of humanity - midterm 3 study guide - Midterm#3...

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