ANTHR101 Lecture Notes - Lecture 12: Orrorin, Foramen Magnum, Mosaic Evolution

• School: University of Alberta
• Department: Anthropology
• Course: ANTHR101
• Professor: Francois Larose

Document Summary

Increased brain to body size ratio: adaptation to bipedal locomotion, gradual reduction in sexual dimorphism, gradual increase in body size, reduced facial prognathism, reduced supraorbital torus (bone above the eyes) Incisors and canines becoming smaller compared to the premolars and molars: non-honing canine complex - when the job is closed the canines rub against each other keeping them sharp. Increased dependence on tools for survival e. g. fire, clothing etc: origins of bipedalism, carrying weapons, tools, infants, food, travelling between food trees, and feeding from bushes, anatomy of bipedalism. Foramen magnum - where the spinal cord connects to the brain. When a organism is bipedal the foramen magnum will be closer to the center of the skull. Those who are quadrupedal have the foramen magnum closer to the back of the skull: pelvis - when on two legs to pelvis is typically wider and thicker to support the extra body weight distributed across fewer limbs.