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Chapter 34 “Humans”

Chapter 34 “Humans”. Charles Page High School Stephen L. Cotton. Section 34-1 Primates and Human Origins. OBJECTIVES: Describe the characteristics and primates. Section 34-1 Primates and Human Origins. OBJECTIVES: Compare New World monkeys with Old World monkeys.

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Chapter 34 “Humans”

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  1. Chapter 34“Humans” Charles Page High School Stephen L. Cotton

  2. Section 34-1 Primates and Human Origins • OBJECTIVES: • Describe the characteristics and primates.

  3. Section 34-1 Primates and Human Origins • OBJECTIVES: • Compare New World monkeys with Old World monkeys.

  4. Section 34-1 Primates and Human Origins • The study of human origins is an exciting, and often controversial, search for our past • has often been spiced with competition among scientists who have different interpretations of the data gathered about our past

  5. Section 34-1 Primates and Human Origins • But, all researchers agree on certain basic facts • humans evolved from common ancestors we share with other living primates, such as apes and chimpanzees • our species almost certainly evolved in Africa, then spread

  6. Section 34-1 Primates and Human Origins • The first Homo sapiens appeared around 500,000 years ago • practically the day before yesterday on an evolutionary scale • dinosaurs had been extinct for more than 60 million years

  7. Section 34-1 Primates and Human Origins • What are Primates? Animals that share several important adaptations, many of which are very suitable for a life spent mainly in trees • faces are flatter than most other animals- eyes point forward, snout is reduced

  8. Section 34-1 Primates and Human Origins • This allows both eyes to inspect the same area at the same time- called binocular vision, or stereoscopic vision • equips primates with a three-dimensional view of the world • handy when judging distances and location of tree branches

  9. Section 34-1 Primates and Human Origins • Primates have flexible fingers (and some flexible toes) that can curl around objects- grasping • arms are also well-adapted to swinging and climbing, because they rotate in broad circles around the shoulder

  10. Section 34-1 Primates and Human Origins • Primates have a large and complicated cerebrum • display complex behavior • mothers take care of their young for a much longer time • complicated social behavior- friendship, adopt orphans, & unfortunately-war among rivals

  11. Section 34-1 Primates and Human Origins • How Did Primates Evolve? • In their early history, primates split into several lines • those that evolved from 2 of the branches look like typical “monkeys” and are called prosimians (simian means “flat-nosed”)

  12. Section 34-1 Primates and Human Origins • Living prosimians include lemurs, lorises, and aye-ayes (bottom of page 758) • almost entirely nocturnal, have large eyes for seeing in dark • More familiar primates include monkeys, apes, and humans- called anthropoids (or human-like primates)

  13. Section 34-1 Primates and Human Origins • The anthropoids have over time given rise to several major primate branches • 2 anthropoid branches- the two major groups of monkeys and apes- separated about 45 million years ago-result of the moving continents, no longer connected by land bridges

  14. Section 34-1 Primates and Human Origins • One branch- the New World monkeys- evolved into the monkeys found today in Central and South America • the term New World comes from the days of Columbus when the Americas were called the New World

  15. Section 34-1 Primates and Human Origins • New World monkeys are virtually tree dwellers, and many have prehensile (grasping) tails that aid in balance and movement through tree branches • Figure 34-3, page 759

  16. Section 34-1 Primates and Human Origins • The other anthropoid group evolved into the Old World monkeys and the great apes • do not have prehensile tails • includes baboons and macaques - page 759 • may live in trees or on ground

  17. Section 34-1 Primates and Human Origins • The great apes, also called hominoids, include gorillas, gibbons, orangutans, chimpanzees, and Homo sapiens

  18. Section 34-2 Hominid Evolution: Human Ancestors • OBJECTIVES: • Describe the importance of various hominid adaptations.

  19. Section 34-2 Hominid Evolution: Human Ancestors • OBJECTIVES: • Discuss the evolutionary trends in hominids that led to Homo sapiens.

  20. Section 34-2 Hominid Evolution: Human Ancestors • Some time between 4 and 9 million years ago, the hominoid line in Africa gave rise to a small group of species called hominids- • not yet human, but had several evolutionary trends that distinguish them from other hominoids

  21. Section 34-2 Hominid Evolution: Human Ancestors • What are Hominids? • Were omnivores that ate both meat and vegetable foods as modern humans do • the spinal column, hip bones, and leg bones changed to make it easier to walk upright on two legs

  22. Section 34-2 Hominid Evolution: Human Ancestors • This bipedal locomotion ( two-foot) was important- it allowed free hands to use tools • the thumb became more independent from the fingers • an opposable thumb enabled ancient hominids to grasp objects to use as tools

  23. Section 34-2 Hominid Evolution: Human Ancestors • There was also a significant increase in brain size, exceptionally large even for primates • chimpanzee: brain size of about 280 to 450 cubic centimeters (cm3) • Homo sapiens: 1200 to 1600 cm3

  24. Section 34-2 Hominid Evolution: Human Ancestors • Most of this difference in brain size results from the enormously expanded human cerebrum • the “thinking” area of the brain • How Did Hominids Evolve? • To follow this story, we need fossils of human ancestors

  25. Section 34-2 Hominid Evolution: Human Ancestors • Much of our recent evidence comes from a small area in eastern Africa between Tanzania and Ethiopia • here, several researchers have found fossils of several species of hominids dating from about 4 million to 1.5 million years ago

  26. Section 34-2 Hominid Evolution: Human Ancestors • Australopithecus: the First Hominids • the first hominid fossil to be found, a nearly complete skull of a young child, was discovered in South Africa in 1924- placed in a new genus called Austropithecus

  27. Section 34-2 Hominid Evolution: Human Ancestors • Since it was from a child, it could not be used to determine how adults looked • but, 12 years later, fossils from an adult australopithecene were found- a hip bone, indicating Australopithecus walked upright

  28. Section 34-2 Hominid Evolution: Human Ancestors • Walking erect was an essential step in the evolution of our species from an apelike ancestor • many more complete homonid fossils have since been found • 1974- Donald Johanson and Tim White found a nearly complete skeleton

  29. Section 34-2 Hominid Evolution: Human Ancestors • It was clear that this was the skeleton of a female, and the fossil has since been called Lucy • Figure 34-5, page 761 • named from the Beatles song “Lucy in the Sky with Diamonds” which they listened to in the camp that night

  30. Section 34-2 Hominid Evolution: Human Ancestors • In 1977, anthropologist Mary Leakey made an equally exciting discovery: a set of fossil hominid footprints- dated at 4 million years old • probably from a parent and child; gave clear evidence that the animals walked erect

  31. Section 34-2 Hominid Evolution: Human Ancestors • In recent years, other hominid fossils have been placed in the genus Australopithecus • current studies suggest there were at least 4 species: • A. boisei, A. robustus, A. afarensis, and A. africanus • (letter “A.” represents genus)

  32. Section 34-2 Hominid Evolution: Human Ancestors • These lived between 4 and 1.5 million years ago; walked upright; and had much smaller brains than present-day humans • Many questions as to how these species were related to each other, as well as to human evolution, still remain to be answered

  33. Section 34-2 Hominid Evolution: Human Ancestors • For a while, australopithecines were the only known links in the chain of human evolution • Then, anthropologist Richard Leakey found another fossil with a smaller face, and a significantly larger brain- he placed it in our genus, Homo

  34. Section 34-2 Hominid Evolution: Human Ancestors • Fossils of this hominid were found with tools made of stone and bone • to emphasize this fact, scientists have called these hominids Homo habilis, which appropriately means “handy man”

  35. Section 34-2 Hominid Evolution: Human Ancestors • Near one of these fossil finds of Homo habilis, in a valley in Kenya called Olduvai Gorge, is the oldest human settlement yet discovered • inside, the floor is littered with animal bones and stone tools; don’t know how they were used

  36. Section 34-2 Hominid Evolution: Human Ancestors • Evidence suggests that Homo habilis disappeared within a few thousand years, and was replaced by a larger-brained species called Homo erectus • “man who walked upright” • by 1 million years ago, had spread over most of the world

  37. Section 34-2 Hominid Evolution: Human Ancestors • The cranial capacity was over 800 cm3; was an excellent toolmaker • carefully made hand axes • charred animal bones around fire sites • indicates using fire for cooking

  38. Section 34-2 Hominid Evolution: Human Ancestors • From a site in France dated at about 400,000 years old, the remains of primitive huts have been discovered • not too different from some still in use in parts of the world today • Figure 34-7, page 762

  39. Section 34-2 Hominid Evolution: Human Ancestors • About 500,000 years ago, the first hominids assigned to our own species (Homo sapiens) first appeared • would not be easily recognizable as modern humans

  40. Section 34-2 Hominid Evolution: Human Ancestors • Around 150,000 years ago, a new hominid walked on Earth • first discovered in the Neander valley in Germany, this species was called Neanderthal man, or Homo neanderthalensis • not like seen in movies; probably much like us

  41. Section 34-2 Hominid Evolution: Human Ancestors • The first hominids truly identical to modern humans appeared in locations scattered throughout the Old World roughly 100,000 years ago • these large-brained people, called Cro-Magnon, were more slender than Neanderthals

  42. Section 34-2 Hominid Evolution: Human Ancestors • Had a more complex culture; made a variety of stone and bone tools, including spear points, knives, chisels, and needles • more talented artists; cave work • now classified as modern humans: Homo sapiens sapiens

  43. Section 34-2 Hominid Evolution: Human Ancestors • Most paleontologists interpret the dates of Cro-Magnon fossils found throughout the world as indicating that modern humans originated in Africa, and from there spread out over the rest of the world

  44. Section 34-2 Hominid Evolution: Human Ancestors • Other scientists say that modern humans evolved from Neanderthals in several regions, including Europe, the Middle East, and Asia • There is no clear resolution to this complex debate at this time

  45. Section 34-2 Hominid Evolution: Human Ancestors • However and wherever the Cro-Magnon originated there is ample fossil evidence that they lived side by side with Neanderthals for some time • around 30,000 years ago, the Neanderthals disappeared

  46. Section 34-2 Hominid Evolution: Human Ancestors • Some scientists believe that the Cro-Magnon interbred with Neanderthals, blending their characteristics • Others believe that the more intelligent Cro-Magnon slaughtered their older relatives, but there is no evidence of this

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