1. Adaptations: Bipedalism Brain Size Hand Functions Teeth – size and shape Social Structures Reproduction Mother-Infant Relationship Communication Culture – art, religion Skin Colour

2. Habitual Bipedalism  Bipedalism – to habitually walk on two legs. Humans only primate with this adaptation  What had to happen for us to stand up straight?

5. Bipedalism…  Structural changes required for us to walk upright: 1. S-shaped spine 2. Double arched foot 3. Pelvis – shorter and wider 4. More gluteus muscles 5. Fewer head / neck muscles – therefore a bigger brain

6. Advantages of Being Bipedal  Free hands for carrying  Can walk longer distances  Can have a continuous good view of surroundings

7. Disadvantages of Being Bipedal  Highly dangerous birthing process  Offspring very dependent and weak because the skull must grow outside of the womb

8. Hominids and Brain Size  Humans have the largest brain for our body mass compared to other mammals

9. Refinements in Hand Structure -  A fully opposable thumb gives the human hand its unique power grip (left) and precision grip (right).

10. Tooth Size Comparison

11. Hominid (human), Primate differences: PrimatesHominids / Humans Social structures Dominance Hierarchies Alpha males in a group Grooming Related to the hierarchies Pair Bonding AND Group Living Humans are the only primates to have both social characteristics simultaneously

12. Hominid (human), Primate differences PrimatesHominids / Humans ReproductionEstrus cycle (in heat) No choice of when to mate Who gets to mate when ties into dominance and grooming hierarchies No estrus cycle Choice in when to mate

13. Hominid (human), Primate differences PrimatesHominids / Humans Mother – Infant relationship Long infant dependency compared to other mammals Important in learning survival skills and culture Longest infant dependency period of all primates

14. Hominid (human), Primate differences PrimatesHominids / Humans CommunicationFacial displays, call, touch, gestures, non- verbal cues Speech centre in the brain Development of Broca’s area of the brain (language), Frontal Cortex (abstract thought), Hyoid Bone (chin to neck bone/muscle attachment), Capacity for memory in various areas of the brain (cerebellum, prefrontal cortex, temporal lobe)

15. Culture Horse in world's oldest painted prehistoric cave, 15,000-10,000 BC Lascaux, France Dagger Carvings – Stonehenge http://www.youtube.com/watch?v =_pXtHqAGN6E

16. Humanity and Our Variations  Our bodies are essentially 50 000 years old.  Now culture, not physical evolution enables us to adapt very quickly to a changing environment  Race - Cultural construct – does not physically exist

17. Skin Colour - Legitimate Explanations for Human Variation  Sunlight is the best source of vitamin D (necessary for healthy bones – helps in the absorption of calcium)  Light skin absorbs vitamin D and burns more easily than darker skin Paler skin is found in areas further from the equator where there is less sunlight ( environmental Fitness)  Skin colour ( variation)