1. HUMAN EVOLUTION (knicked from Hamish) Slide 2Where we fitWhere we fit Slide 3 Primate family treePrimate family tree Slide 4 HominoidsHominoids Slide 5Primate featuresPrimate features Slide 6Ape featuresApe features Slide 7Ape vs. Human - skeletalApe vs. Human - skeletal Slide 8Ape vs. Human – skullApe vs. Human – skull Slide 9Ape vs. Human – brainApe vs. Human – brain Slide 10Ape vs. Human – otherApe vs. Human – other Slide 11Selection PressuresSelection Pressures Slide 12BipedalismBipedalism 3A BIO

2. WHERE HUMANS FIT IN Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Family: Hominidae Genus: Homo Species: sapiens Fur wearin’, warm blooded, young bearin’, milk sucklers. Adapted to arboreal life (living in the trees). Man-like. Let’s include our ancestors and great apes. Man The thinking man! To find our place it’s worth studying our taxonomic position… Main Menu

3. PRIMATE FAMILY TREE Evolutionary speaking… Apes branch off here Main Menu

4. HOMINOIDS Chimps Gorillas Gibbons siamangs Humans Old classification New classification Hominidae Hominidae/ Homininae Hominidae/ Hominidae Pongidae/ Paninae Hylobatidae Hominoid refers to human-like species (all apes and humans). Hominid refers to humans, recent ancestors and great apes. Hominin is used to differentiate man’s ancestors from all else. With recent DNA analysis allowing a more detailed comparison the views of family/subfamily classifications are changing: As our DNA is 98.6% the same as chimps, it has also been suggested that chimps be placed in our Genus, Homo. Orang- utans Pongidae/ Ponginae Hominidae/ Ponginae Manual pg 343 Main Menu

5. PRIMATE FEATURES What are the adaptations for arboreal life that set primates apart? Dexterous hands – for clutching branches (maybe opposable thumb) Sensitive fingertips with skin ridges with nails, not claws Eyes front – need to be good at judging distances Colour vision – recognise ripe fruit Poorer sense of smell, but emphasis on fine vision Single offspring and extended parental periods - importance of learned behaviour Mobile hip and shoulder joints Unspecialised dentition – omnivorous diet Big bwain we got Strong social organisation Manual pg 360 Main Menu

6. APE FEATURES Features of apes: No tail Rib cage is flattened Molars have 5 cusps (monkeys have 4) Locomotion is brachiating, knuckle-walking, or bipedalism. Posture partly (or fully) erect… leaving the hands free Main Menu The Y5 molar pattern

7. APES vs HUMANS 1 Major skeletal differences S –shaped spine Pelvis is wide and femur comes in (valgus angle); centre of mass is mid-line of body and above the hips knee joint bigger, big toe not opposable (much), foot arched – all for walking Great thumb and fingers are less curved – for tool use rather than brachiating Main Menu

8. APES vs HUMANS 2 Skull differences Foramen Magnum position is vertical – balanced bipedalism and therefore no nuchal crest (muscle attachment point) Brow ridge Protruding muzzle Diastema Sagittal crest (jaw muscle attachment) Zygomatic arch (jaw muscle passes through) Forehead slope Canine size Molars (indicates diet) Nuchal crest (neck muscle attachment) Nose width Cranial capacity (as a proportion of body size) Manual pg 360Main Menu

9. APES vs HUMANS 3 Brain developments Human have a large brain (1400cm 3 vs. ~ 450cm 3 ) Brain includes well-developed cerebral cortex (the folded surface) - memory - speech (Broca’s area) - understanding of language (Wernicke’s area) Cerebellum (balance and coordination) more developed – bipedal locomotion and tool use Manual pg 364 Main Menu Cerebellum Wernicke’s areaBroca’s area

10. APES vs HUMANS 4 More sweat glands Finer, and shorter, hair Larynx is lower and pharynx longer – for complex sounds Other things Smaller teeth – ‘cos we used tools instead, as well as having a more refined diet Rounded jaw – not rectangular Main Menu

11. SELECTION PRESSURES Environment: In Africa around 6 m.y.a. forests were receding, replaced by grassland. This reduced arboreal habitat driving primates onto the ground. Bipedalism: is more energy efficient than knuckle walking – these species can travel further for scarce food. It allows tool use and carrying of young. The body is also kept cooler (less surface area hit by the sun and greater airflow around the body). Height advantage: gained by being upright and being more able to see food and predators. Dentition: due to the nutty and vegetable diet canines reduced and molars enlarged. Hairlessness: reduces parasites, assists cooling. Brain size: increases correlate to tool use 2.5 m.y.a. and more recent developments are thought to be parallel to communication improvements. See manual pg 360 Main Menu

12. BIPEDALISM The change to bipedalism is thought to have been explosive – within 2 million years or less. What could cause such a rapid evolution? More time standing and walking Increased air currents over body Infant less able to grasp mother Infant held more by mothers arms Less body hair beneficial More sweat glands beneficial More forwardly directed big toe Infant less able to grasp mother Manual pg 361, 362 Main Menu