Human Derived Traits Locomotion differences Dental differences Brain differences Life history differences Cultural adaptations

The Hominoidea

Gibbons

Orangutans

Gorillas

Chimpanzees: common and bonobo

Hominoidea Characteristics No tail Larger body size Rely more on vision Suspensory hanging adaptation Y-5 pattern of molars Arms longer than legs (except humans) Increased brain size and intelligence Prolonged growth and development

Differences in the Jaws and Teeth Apes have large anterior teeth which results in a larger face than humans

Apes: Large canines Canine diastema (space for opposing canine) Sectorial premolar (sharpens upper canine) Thin molar enamel

Humans: Small canines Smaller anterior teeth (and a smaller face) Relatively large posterior teeth

Dental arcade shape differences Apes: U-shapedHumans: Parabolic, indicates – Reduction in size of canine Loss of diastema & sectorial premolar

Structural similarities exist between human and ape brains Same landmarks are found on both What’s different? Brain Differences

Human Brain – Enlargements and Elaboration of the Cerebral Cortex Frontal lobes – association areas that create more complex models of reality Areas associated with language on dominant hemisphere Broca’s area: motor speech Wernicke’s area: language comprehension

Locomotion Differences: Humans are obligate, habitual bipeds Requires erect posture Slow, but energy efficient Birth and lower back problems Precarious “…the body, step by step, teeters on the edge of catastrophe” (Napier 1967:56)

Position of Foramen Magnum Centered to balance skull on vertebral column in an upright position

Quadruped – only has a primary curve Vertebral column is not weight-bearing, vertebrae of equal size Secondary vertebral curves in humans – neck and lumbar Vertebrae increase in size from top to bottom Vertebral Column

Morphological Differences in the Pelvis APE Tall and narrow Flat, or compressed anterior to posterior (front to back) HUMAN Short and broad Curved