Human Evolution

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Human Evolution
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Paleoanthropology

• Paleoanthropology is the scientific study of
  human evolution
• Smithsonian Institution FAQ
• PBS evolution library

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Primates

• The mammalian order primates include
• Prosimians
• Monkeys
• Apes
• Humans
• Primates evolved from an ancestor that lived 60
  m.y.a approx.

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Important Primate Features

• Grasping hands and feet
• Babies can hold onto their mothers
• Grip limbs, seize food
• Forward facing eyes
• Binocular vision with depth perception
• Flexible shoulder and hip joints
• Nails instead of claws
• Diverse behaviors and social structures

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First primates

• Primates are divided into two groups Prosimians
  and Anthropoids
• Prosimians were common 38 mya. Few survive today,
  tarsiers, lorises, lemurs
• Found in Southeast Asia and Madagascar.
• Tarsier from India.
• Lemurs from Madagascar
• Small in size, large eyes, most nocturnal

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Anthropoids

• Anthropoids are divided into Monkeys and
  Hominoids
• Hominoids are divided into Apes and Humans
• The evolution of color vision, bigger brains and
  diurnal behavior are seen today in monkeys
• Monkeys evolved in Africa and migrated to Asia
  and to the Americas.
• Were first have opposable thumb used for
  grasping

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Old World and New World Monkeys

• Old World Monkeys
• Tree and ground dwelling
• Straight tails
• Small to larger varieties
• live in the hot and dry areas of Africa, some
  live in the cold areas of Japan
• New World Monkeys
• arboreal
• Prehensile tails
• small

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Old World and New World Monkeys
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Hominoids

• Hominoids are classified as apes and humans
• Apes include gibbons, orangutans, chimpanzees,
  bonobos and gorillas
• Apes lack tails, have long muscled forelimbs for
  climbing and swinging through trees. Walk upright
  with support from their forelimbs
• Some arboreal, some live on ground
• Humans have larger brains and walk upright

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Hominoids evolve in Asia and Africa

• The climate started to cool as hominoids evolved
  in Africa and Asia
• Fossils give one line of evidence
• DNA gives another. Gibbons were first to evolve,
  followed by the orangutans, found in Southeast
  Asia.
• Then the African apes, chimpanzees and gorillas
  evolved.
• One species of African apes was the ancestor of
  modern humans
• Did Humans Evolve? video clip

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Hominids

• Hominids are African apes and humans (not
  orangutans or gibbons)
• Hominids are primates that walk on two legs.
• Walking Tall
• Between 5 and 8 mya in Africa one line evolved
  into African apes gorillas and chimpanzees. The
  other line into humans
• As climate changed becoming dryer, early humans
  walked on the ground. Speed, avoid predators.
  Hands freed to hunt, feed protect young and use
  tools

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Australopithecus africanus

• Hominid ancestor that walked upright (discovered
  1924), called Taung child.
• The position of the foramen magnum, the opening
  in the skull where the spinal cord leaves the
  brain, showed that the organism walked upright
  1-2 million years old
• Australopithecine name means early hominid
  that lived in Africa with apelike and human like
  qualities.

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Lucy

• Discovered by Donald Johanson (finding Lucy) in
  1974, this fossil dated at 3.5 mya. He proposed a
  new species, Australopithecus afarensis.
• Apelike shoulders and forelimb
• Human-like pelvis and could walk upright
• Larger brain
• Genus Australopithecine disappear about 1mya
• Larger more robust hominids with bigger teeth
  were found and dated to be 1.5 my. Named
  Paranthropus, these lived at the same time as
  Australopithecines
• The relationship among these is unknown

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Laetoli footprints

• Discovered in Tanzania in 1978 by Mary Leakey's
  group, the footprints of human-like ancestors are
  3.6 my old.
• Laetoli footprints
• A. afarensis was the most likely hominid to make
  the prints.
• Explore further

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Lucy
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Modern humans

• In 1964 Louis and Mary Leakey found a 1.5 to 2 my
  old fossil, named it Homo habilis meaning handy
  human.
• Found with stone tools, name means first
  toolmaker.
• May have scavenged
• Brain volume of 600 -700 cm3
• Modern humans average 1350cm3
• Larger than 400-500 cm3 of australopithecines

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Homo habilis
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Hunting and using fire

• A new hominid species arose 1.6 mya named Homo
  erectus
• Erect stature
• Larger skull
• Stone tools, axes
• Hearths with charred bones
• may have lived in caves
• Migrated from Africa 1 mya spread to Asia and
  maybe Europe
• Became extinct between 300,000-500,000yrs ago
• More human-like descendents may have arisen from
  H. erectus before they went extinct.

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Homo erectus
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Homo sapiens

• Fossils of Homo sapiens appear in Africa, the
  Middle East and Asia about 100,000- 400,000 yrs
  ago.
• Braincase larger than H. erectus,
• Less prominent brow ridges
• Best known of these early H. sapiens were the
  Neanderthals (Homo Neanderthalensis)
• Lived from 35,000 100,000 yrs. Ago in Europe,
  Asia and Middle East
• Thick bones, prominent faces
• Lived in caves, used tools, buried dead, may have
  had religious views and spoken language

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Neanderthal
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What happened to Neanderthals?

• About 35,000 40,000 yrs ago Cro-Magnons spread
  through Europe.
• Identical to modern humans in height, skull,
  teeth and brain size.
• Tool makers, artists
• Unlikely that Neanderthals evolved into
  Cro-Magnons. Fossil evidence suggests that they
  were a side branch of modern humans
• Genetic evidence supports the origin of modern
  humans in Africa as early as 200,000yrs ago

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Out of Africa

• Humans have remained anatomically unchanged over
  the last 200,000 yrs, establishing themselves in
  Africa, Europe and Asia
• About 12,000 yrs ago humans crossed a land bridge
  into N. America.
• By 8000-10,000 yrs ago Native Americans were
  building settlements, farming and domesticating
  animals
• Human evolution activity

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Bering Strait Land Bridge
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Evolution of Skin Color Black and White

• Skin color hypothesized to be related to the
  amount of ultraviolet light received.
• Those that are in areas that receive excess UV
  rays have darker skin those areas that receive
  too little have lighter skin. Natural Selection
  is responsible
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