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Hominin Evolution. Pre-dating Australopithecus. Hominins discovered in north-central and eastern Africa Bipedal – debatable in some species We will focus on the species for which there is ‘stronger’ evidence of bipedalism. Ardipithecus ramidus. Middle Awash area of Ethiopia
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Pre-dating Australopithecus • Hominins discovered in north-central and eastern Africa • Bipedal – debatable in some species • We will focus on the species for which there is ‘stronger’ evidence of bipedalism
Ardipithecusramidus • Middle Awash area of Ethiopia • Approximately 4.4mya • Found: • Dental • Cranial • Post-cranial remains
Ardipithecus ramidus • Indicators of Bipedalism • Foramen magnum location • Femur and pelvis • Humerus – chimp features, but not weight bearing • Foot Phalanges – curved like apes
Ardipithecus ramidus • Ardi = “facultative” biped • What do you think this term mean? • Living in both worlds: up in the trees at times while also on the ground
Australopithecus afarensis • East Africa • Hadar, Ethiopia • Laetoli, Tanzania • 3.6-3.0 mya • Forest, woodland, grassland
A. afarensis – Traits Bipedal • Vertical foramen magnum • Heel-knee joint human-like Some Arboreal Abilities Retained • Curved phalanges • Long arms for body size
Type Fossil – “Lucy” • Found: 1974, Hadar, Ethiopia • 40% complete skeleton • Both arms • Much of the pelvis • Left femur, right tibia • Hand and Foot bones • Adult (based on 3rd molar) • Female?
Type Site: Laetoli Footprints • Tanzania • 3.6 mya • 75 feet long preserved • Walked over volcanic ash, rained, hardened • 3 hominins: • 2 adults, 1 child
A New Hominin • Australopithecus sediba • Discovered in 2008; located in South Africa • Proposed by some to be the best candidate ancestor for the genus Homo
A New Hominin • Features: • Small brain • Pelvis – mixture of Australopithecus-like and Homo-like features • Hand – combination of ape- & human-like • Foot & ankle shape – combination of ape- & human-like
The Genus Homo – Overall Trends • Characterized by: • Increased brain size • Increased body size • Diet expands • Meat incorporation • Reliance on material culture: • Stone tool use • Fire and cooking
Introduction To Homo habilis • Contemporaneous with australopithecine remains • Anatomically different than specimens assigned to the genus Australopithecus • Distinguishing feature – cranial size • H. habilis shows an increase in cranial size as compared to Australopithecines
Homo habilis – OH 24 • Location: Olduvia Gorge • Comparison to Australopithecines: • Larger brain • Less protruding face “Twiggy” or OH 24 Dated to ~ 1.8mya