week3_hominids

week3_hominids - Evolution Pan troglodytes and...

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Unformatted text preview: Evolution Pan troglodytes and Australopithecus afarensis Homo sapiens Homo neanderthalensis Evolution and Natural Selection Natural Selection: a process through which certain characteristics of organisms are passed to succeeding generations at the expense of other characteristics. Evolutionary Trends in Primates Climate Change Locomotion (from brachiation to bipedalism establishment of `home bases' changes in diet development of complex social organization What is human? Large brain? Bipedal locomotion? Tool manufacture and use? Language? Art, religion, etc.? The First Hominids Ardipithecus ramidus 4.4 - 5.8 million years BP bipedal Wooded environment Important for apehominid split Australopithecines 4.4 1.0 million years BP Found in east and south Africa Savanna environment Several different kinds of Australopithecines: gracile and robust Australopithecines 5 mya 4 mya 3 mya 2 mya 1 mya Present Homo habilis Homo erectus Australopithecus garhi Ardipithecus ramidus Australopithecus afarensis Homo sapiens Homo neanderthalensis Australopithecus africanus Australopithecus anamensis Australopithecus robustus Australopithecus boisei Australopithecus aethiopicus Australopithicines: two varieties Gracile versus Robust Gracile Australopithecines Bipedal c. 4-2 million years BP Small in stature Sexual dimorphism? No specialized teeth South and east Africa Examples of gracile australopithecines Taung baby (A. africanus) Mrs. Ples (A. africanus) Sterkfontein (A. africanus) Lucy (A. afarensis) Laetoli footprints (? From A. afarensis?) A. garhi Australopithecus afarensis Australopithecus garhi Human-like femur Large molars Robust Australopithecines Bipedal c. 3-1 million years BP Pronounced sagittal crest Post-orbital constriction Specialized teeth Robust Australopithecines 5 mya 4 mya 3 mya 2 mya 1 mya Present Homo habilis Homo erectus Australopithecus garhi Ardipithecus ramidus Australopithecus afarensis Homo sapiens Homo neanderthalensis Australopithecus africanus Australopithecus anamensis Australopithecus robustus Australopithecus boisei Australopithecus aethiopicus Australopithecines: Evolutionary Trends Biology Moderate increase in brain size Reduction in front dentition Increase in rear dentition Australopithecines: Evolutionary Trends Biology Moderate increase in brain size Reduction in front dentition Increase in rear dentition A. robustus A. anamensis A. africanus Australopithecines: Evolutionary Trends Behavior Biology Moderate increase in brain size Reduction in front dentition Increase in rear dentition Bipedalism (preceded increased brain size) Change in tool use? Still in the trees? Shared food and home base? Our everchanging reconstruction of the human "family tree" Friday class: The genus Homo What is human? Large brain? Bipedal locomotion? Tool manufacture and use? Language? Art, religion, etc.? Beginnings of the genus Homo SUMMARY Well-documented record extending back c. 4.5 million years BP Variability in australopithecines with two major forms: gracile and robust Co-occurrence of some australopithecines with first members of genus Homo? Fossil evidence of the human lineage: the Genus Homo From Australopithecines to Homo habilis Homo habilis Meaning: 'Handy man'. Lived: 2.4 - 1.6 million years ago. Range: Eastern and southern Africa. Diet: Omnivorous diet. Size: 4 ft./3-inches & 88 lbs. Brain Size: 47% the size of a modern H. sapiens sapiens brain Homo habilis 2.4 1.6 million years BP Tanzania, Kenya (Koobi Fora), S. Africa Australopithecines vs. H. habilis A. africanus H. habilis H. Habilis and Oldowan Technology 2.5 million years ago Found in association with H. habilis, not Australopithecines Chopper-chopping tool technology Crude, but reflects certain mental capacity Biology and Environment of H. habilis Still retained some tree-climbing ability Sexual dimorphism Scavenger Sleeping in trees? Mental ability including foresight Did H. habilis have culture? Stone tools Dramatic increase in meat consumption? Language? Social organization From Homo habilis to H. erectus End of Friday class Next week: Homo erectus Geographic spread of Homo habilis and Homo erectus Homo erectus 1.9 - 0.3 million yrs. ago Between 1.9 - 1.0 mya left Africa China, Indonesia, Hungary, East and West Africa, Germany Multiple species in H. erectus Pleistocene Earliest human ancestors? candidate last ancestor before apes and humans split on the evolutionary tree? Orrorin tugenensis as ...
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This note was uploaded on 08/25/2008 for the course ANTH 151 taught by Professor Sheppard during the Spring '07 term at Hawaii.

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