ANTH 120 1nd Edition Lecture 20 Outline of Current Lecture II. Genus HomoCurrent LectureTrend in Evolution of Homo that distinguish them from Austra. 1. Encephalization (brain size 600 cc) a. Expanded parietal regionsb. Higher frontalc. Rounded occipital contour2. Increasing Body Sizea. Taller b. Modern limb proportionsc. Reduced sexual dimorphism3. Dietary Shiftsa. Smaller jaws and cheek teethb. More parabolic “C-shaped” dental arcadec. Reduced gut morphologyd. Increased reliance on meat and tool useExpensive Tissue Hypothesis: The brain is expensive; basal metabolic rate should be higher(Aiello and Wheeler, 1995)Expected BMR for 65kg primate = 4.4 W/kg=Observed human BMR (65kg) = 4.4 W/kgDespite increases in brain size, resting basal metabolic rate is the same as other primates of similar size!How is it possible to grow a big brain without being metabolically compromised? Reduced gut size! Eat a higher quality diet!These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Higher Diet Quality selection for more complex foraging behaviors Larger Brain Sizes Increased energy availability reduced food bulk/ More rapid assimilation Smaller gut increased energy available larger brainAustralopithecus still had a relatively large gut.Higher frequency of cut marked bones in the archaeological record. Oldowan Tool Industry- Hammerstone- Flake - Core- Oldowan tools are simple flake tools struck from a coreo An anvil technique - Flakes are extremely sharpRecognizing Stone Tools- Hard Hammer percussion- Point of Percussion- Bulb of percussion- Erailleur Scar concavity off of the flake- Ripples- Resulting Flake- Non-standardized- BUT material carried considerable distance- Planning not seen in living primatesEarly HomoHomo habilis (2.8-1.4 mya)- East Africa: Mary and Louis Leakeyo Koobi Fora, Kenyao Olduvai Gorge, Tanzania- South Africao Sterkfontein (Ste53)- OH 7o Bigger Brain (600 cc)o Smaller Cheek teetho Precision grip- OH-24 H. habilis- Stw-53 H. habilis- KNM-ER 1470 Cranial Capacity: 752cco LARGER TEETHo 3 ROOTED PREMOLARSo NO SO TORUSo Slight facial dishingo No M3 reduction Austrapithecus? H. reudolfensis- KNM-ER 1813o 510 cco Smaller Teetho 2 rooted premolarso Supraorbital toruso Flatter faceo Sphericalo M3 reduction Homo? Habilis? More human likeIssues with Homo habilis1. Primitive Homo a. 1470 Austrob. 1813 Homo2. Sexual Dimorphism?a. 1470 maleb. 1813 female3. One species or two?a. 1470 H. redolfensisb. 1813 H.
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