Human evolution and Evidence

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Human evolution and Evidence

• All known hominid (human) fossils older than
  about 1.5 million years are from eastern and
  southern Africa.
• The various pre-homo hominids are classified in
  the genus Australopithecus (southern ape) and are
  known as australopithecines.

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• 3. Researchers must try to reconstruct human
  phylogeny from an incomplete record. One key
  question in paleoanthropology is which of the
  australopithicines were evolutionary dead ends
  and which were either on, or close to, the
  phylogenetic lineage that led to the homo branch

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• 4. The first australopithecine, A. africanus, was
  discovered in 1924 by Raymond Dart in a quarry in
  South Africa.
• a. walked fully erect
• b. human like hands and teeth
• c. brain 1/3 the size of modern humans

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• 5. In 1974, a new fossil, about 40 complete was
  discovered in the afar region of Ethiopia. This
  fossil, nicknamed Lucy, was described as a new
  species, A. afarensis

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• a. Larger brain
• b. prognathic jaw
• c. longer arms for arboreal locomotion
• d. ability for bipedal locomotion (based on
  pelvic fossils and tracks)

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• 6. Two lineages appeared after A. afarensis
• a. the robust australopithecines with sturdy
  skulls and powerful jaws and teeth for grinding
  and chewing hard tough foods
• b. the gracile australopthecines with lighter
  feeding equipment adapted for softer foods.

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• 7. Most researchers agree that the robust
  australopithecines were an evolutionary dead end,
  and that the ancestors of Homo were among the
  gracile australopithecines.

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• 8. The earliest fossils that anthropologists
  place in our genus, Homo, are classified as Homo
  habilis.
• a. these fossils range in age from 2.5 to 1.6
  million years old.
• b. less prognathic jaws
• c. Larger brains(600-800 cm3)
• d. sharp stone tools were used

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• 9. Homo erectus was the first hominid species to
  migrate out of Africa, colonizing Asia and
  Europe.
• a. they lived from about 1.8 million to 500,000
  years ago.
• b. in Europe, H. erectus gave rise to the humans
  known as Neanderthals

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• c. taller
• d. larger brain (1100 cm3)
• e. cave dwelling with fire capabilities

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• 10. The term Neanderthal is now used for humans
  who lived throughout Europe from about 200,000 to
  40,000 years ago.
• a. brain comparable to modern Homo species but
  skull different shape
• b. stockier build
• c. buried the dead
• d. advance stone tools

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• 11. Homo Sapiens
• a. two alternative hypotheses have been proposed
  for the origin of anatomically modern humans.
• b. in the multiregional hypothesis, fully modern
  humans evolved in parallel from the many local
  populations of H. erectus

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• c. the other hypothesis, the out of Africa or
  replacement hypothesis, argues that all Homo
  sapiens throughout the world evolved from a
  second major migration out of Africa that
  occurred about 100,000 years ago.

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• d. this migration completely replaced all the
  regional populations of Homo derived from the
  first hominid migrations.

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• 12. Both hypotheses recognize the fossil evidence
  for humanitys African origin but which has more
  validity at this point?
• a. using changes in mitochondrial DNA among
  human populations as a molecular clock, research
  has reported a time of genetic divergence of
  about 100,000 years ago

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• b. by comparing the Y chromosomes of males from
  various geographic regions, researchers were able
  to infer divergence from a common African
  ancestor less than 100,000 years ago
• c. both these support the replacement hypothesis