Slide 1: Chapter 2: The Star Wars Bar
Slide 2: How many pre-human skeletons/skulls have we discovered so far?  2000 for a 5 million year period
Slide 3: What are the differences between splitters and lumpers among paleoanthropologists?  splitters: think small differences are important-->split into many separate species  lumpers: think small differences unimportant--> lump into a few large species with wide variation
Slide 4: Human Evolution as a Bush
Slide 5: Human Evolution as a Bush
Slide 6: What is the difference between picturing evolution as a tree or a bush?  tree: Homo sapiens seen as a goal [fruit] of evolution  bush: Homo sapiens just one of many possible outcomes-->chance and environment determine outcome
Slide 7: For how long has our species been the only hominid on earth?  30,000 years
Slide 8: How does this affect our view of the probability of evolution?  We tend to see ourselves as goal or peak of evolutionary process  We assume there has always been just one single hominid on earth-->that is exception, not rule
Slide 9: The March of Evolution ~ NOT true!
Slide 10: How does the Star Wars bar scene help us think of evolution differently?  Aliens from all parts of galaxy coexisting at one time  Hominids at different stages of evolution co-existing
Slide 11: The Star Wars Cantina
Slide 12: The Star Wars Cantina: The Fossil Evidence
Slide 13: Why did Charles Darwin think Africa was the place to look for evidence of early human evolution?  Oldest known civilizations in Africa: Egypt  Biggest continent with widest variety of life forms and hospitable climate  Native habitat for most human-like apes: gorillas and chimpanzees
Slide 14: Discoveries of Human Ancestors in Africa
Slide 15: How popular was Darwin's hypothesis in the 19th century? Where did people prefer to look? Why?  19th century European racists had prejudiced views of Africans  Asia most populous continent with highly respected civilizations
Slide 16: Why were the discoveries of Robert Broom in Africa so important?  confirmed Africa as home of original humans  several species of Australopithecus found there
Slide 17: Robert Broom
Slide 18: What were the most favored habitats [kinds of places] of Australopithecus?  forest fringes  open grasslands  woodlands  herbivorous diet supplemented by scavenging meat from dead carcasses
Slide 19: The New African Environment
Slide 20: Robert Dart s Discovery: The Taung Child
Slide 21: What was Robert Dart's hypothesis about the social behavior of Australopithecus?  early human ancestors were violent, bloodthirsty killer-apes  Reflected violent decades from World War I through World War II: 1914-1945
Slide 22: What was his evidence for this thesis?  he found concentrations of pierced human skulls  concluded they were brought there by ritual killing
Slide 23: What is the preferred hypothesis explaining this evidence today?  holes in human skulls were inflicted by animals who preyed on vulnerable hominids
Slide 24: Kidnapping the Taung Child s
Slide 25: What was so unconventional about the training and education of Louis and Mary Leakey?  parents were Christian missionaries working in Africa  both lacked official university degrees or institutional sponsor
Slide 26: Why was "Piltdown Man" so eagerly accepted as a genuine discovery by paleoanthropologists of the early 20th century?  it fit preconceived model: big brain with ape body  located in culturally prestigious Europe->most "civilized" continent
Slide 27: The Piltdown Hoax: So Believable!
Slide 28: What are the oldest surviving human tools?  primitive tools used to smash nuts and bones
Slide 29: The Oldest Stone Tools
Slide 30: How do we know they were even made by anyone?  chipped flacks used as cutting edges for flesh  high density of smashing tools couldn't be the result of chance
Slide 31: What were the two most significant new features of Homo habilis?  Homo habilis: "handy man"  Brain size: 700 cc. [Australopithecus= 500cc]
Slide 32: Hominid Brain Growth
Slide 33: Homo habilis 1
Slide 34: Homo habilis 2
Slide 35: Homo habilis 3
Slide 36: Homo habilis 4
Slide 37: Homo habilis 5
Slide 38: Homo habilis 6
Slide 39: What were the major differences between the two types of hominids about 2 million years ago?  vegetarians: Australopithecus  meat-eating scavengers: Homo habilis
Slide 40: What were the important environmental changes about 2.5 million years ago that sparked the emergence of Homo habilis?  period of intense weather change  bouts of warming followed by intense cooling  lower temperatures--> further shrinking of forests  omnivores ate greater diversity of food-> won out over more specialized herbivores
Slide 41: The Range of Habilis Habitat
Slide 42: Where is Olduvai Gorge?  former lake lake region in Kenya
Slide 43: Olduvai Gorge in Kenya
Slide 44: Why is it such a rich site for the discovery of earlier hominids?  possessed rich bio-mass to support large animal population--> many surviving fossils  near water holes and nearby volcanoes  now parched to reveal lower layers each spring
Slide 45: How was the increased brain size of Homo habilis related to its new kind of diet?  could make more efficient tools  could better locate likely animal carcasses  could gain access to protein-rich bone marrow
Slide 46: Homo habilis using stone tools to eat bone marrow
Slide 47: How did this new brain and diet affect Homo habilis' chance of surviving in a new, unstable environment?  highly concentrated bone-marrow protein necessary for rapid brain growth  bone marrow available at all seasons
Slide 48: Kenyan Stamps on Human Evolution
Slide 49: Where Does Homer Fit?