Human Evolution

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Human Evolution

• 14-1 The Evolution of Primates
• 14-2 Early Hominids
• 14-3 The Human Line

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The Evolution of Primates

• Primates the mammalian group that includes
  prosimians, monkeys, apes, and humans

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First primates evolved about 60 mya

• Primates were more fit than their ancestors
  because they had grasping fingers (opposable
  thumb) and toes and their eyes shifted forward to
  the front of the face

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The First Primates Were Prosimians

• Pro before
• Simia ape
• Only a few kinds of prosimians survive today
• Lemurs are in danger of extinction

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Diurnal Primates are Called Monkeys

• 36 mya primates became diurnal
• Diurnal primates are active during the day and
  sleep at night
• Vision is important for daytime hunting and
  evolution favored improvements in eye design
• Cone cells gave primates color vision
• Larger, more complex brain

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Humans Evolved from Apes

• Fossil evidence indicates that humans evolved
  from the evolutionary line that gave rise to apes
• Modern apes include gibbons, orangutans,
  gorillas, chimpanzees, and bonobos
• Apes have larger brains than monkeys and do not
  have tails
• Humans and apes have very few differences in DNA
  sequences

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Early Hominids

• 15 mya the Earths climate cooled
• The great forests were replaced with open
  savannas
• 4 mya natural selection resulted in the resulted
  in the divergence of the human line from the
  gorilla/chimpanzee line

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Australopithecines Were the First Hominids

• Our earliest known direct ancestors
• Exhibited two milestone characteristics
• They were bipedal
• They had large brains

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The Discovery of Australopithecus

• Lucy
• The most complete and best preserved skeleton of
  a prehuman hominid ever discovered
• 3.2 million years old
• Australopithecus afarensis
• Probably the ancestors of all australopithecines
  and modern humans

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The Human Line

• We are the third and only surviving species of
  humans (genus Homo)
• The first humans evolved from australopithecines
  2 mya

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Homo habilis Was the First Member of Our Genus

• Homo man
• Habilis handy
• Homo habilis
• Brain size larger than australopithecines
• Made and used tools
• Lived in Africa
• Extinct

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Homo erectus Evolved Next

• Evolved in Africa 1.5 mya
• Migrated to Europe and Asia
• Lived in groups
• Produced efficient stone tools
• Used fire
• Taller and larger brains than H. habilis
• Extinct

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The Neanderthals Homo sapiens neanderthalensis

• Powerfully built, short, stocky, massive skulls,
  very large brains
• Buried their dead with weapons, food, flowers
• First hominids to how evidence of abstract
  thinking
• Fossil evidence disappears about 30,000 years ago
• Some scientists believe they evolved into modern
  humans
• Some scientists believe they just went extinct
  and are not directly related to the modern human

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Modern Humans are Homo sapiens

• DNA evidence suggests that Homo sapiens evolved
  from Homo erectus 500,000 years ago
• Migrated throughout the world
• Increased brain size
• Makes and uses tools effectively
• Uses symbolic language
• Has cultural evolution

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