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Published byMargaretMargaret Dean Modified over 9 years ago
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Early Hominids January 31, 2005
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Part I: Hominid Phylogeny Australopithecus –africanus –afarensis –robustus Homo –habilis –erectus –sapiens
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Hominid Phylogeny
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Australopithecus A. africanus Raymond Dart’s “Taung Child” 3.0-2.5 mya Bipedal Small brain Sexual dimorphism suggests polygyny Partially arboreal Worked in groups
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Australopithecus A. afarensis “Lucy” Fan shaped pelvis 3.8-3.0 mya
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Australopithecus Gracile A. afarensis A. africanus? Robust A. robustus A. boisei A. africanus? Folivore: large molars and sagittal crest Small canines Little sexual dimorphism
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Part II: When did this happen? Geologic time scale:
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How do we know? Relative Dating –Statigraphy –Glaciations –Fluorine analysis –Dendrochronology
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How do we know? Absolute Dating –Carbon 14 (organics, up to 40,000 years) –Potassium Argon (volcanic, over 500,000) –Uranium Series (minerals b/w 1k and 1m) –Thermoluminescence (rocks & minerals b/w 5k and 1 mya) –Electron Spin Resonance (rocks & minerals b/w 1k and 1mya)
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How do we know? Calendars Historical accounts
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Part III: Why did this happen? Ecology: 1) Relationships between organisms and environment. 2) Relationships between human groups and their physical and social environments.
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Climactic Shifts
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Bipedalism Energy efficient locomotion Food gathering Avoiding predators Provisioning offspring Free hands (tools) Tracking prey
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Skeletal Comparison
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Brain Size Homo sapiens sapiens: 1,200-1,350 Modern Chimpanzee: 390 A. afarensis: 430 A. africanus: 490 A. robustus: 540 A. boisei: 490 (Measured in cubic centimeters)
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Skeletal Comparison Human Chimp
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Skeletal Comparison Robust Australopithecus Gracile Australopithecus
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Dental Comparison Modern Chimp A.afarensisH. sapiens Upper jaw
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Part IV: What does it mean? Killer Ape –Osteo-donto-keratic tools Man the scavenger –Probably vegetarian or omnivorous
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What does it mean? Savannah hypothesis Variable selection –Phenotypic plasticity
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What does it mean? Bipedalism or Intelligence? Piltdown hoax
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What does it mean? Piltdown hoax
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