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 caninesSmaller anterior teeth (and a smaller face)

Relatively large posterior teeth

Dental arcade shape differences

Apes: U-shaped Humans: 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