1. Slide 1 of 20 Copyright Pearson Prentice Hall Biology

2. Slide 2 of 20 Copyright Pearson Prentice Hall 15-1 The Puzzle of Life's Diversity

3. 15-1 The Puzzle of Life's Diversity Slide 3 of 20 Copyright Pearson Prentice Hall 15-1 The Puzzle of Life's Diversity Evolution is the process by which modern organisms have descended from ancient organisms. A scientific theory is a well-supported testable explanation of phenomena that have occurred in the natural world. 15-1 The Puzzle of Life's Diversity

4. 15-1 The Puzzle of Life's Diversity Slide 4 of 20 Copyright Pearson Prentice Hall Voyage of the Beagle In 1831, Darwin set sail from England aboard the H.M.S. Beagle for a voyage around the world. Darwin went ashore and collected plant and animal specimens for his collection. He studied the specimens, read the latest scientific books, and filled many notebooks with his observations and thoughts.

5. 15-1 The Puzzle of Life's Diversity Slide 5 of 20 Copyright Pearson Prentice Hall Voyage of the Beagle

6. 15-1 The Puzzle of Life's Diversity Slide 6 of 20 Copyright Pearson Prentice Hall Voyage of the Beagle What was Charles Darwin's contribution to science?

7. 15-1 The Puzzle of Life's Diversity Slide 7 of 20 Copyright Pearson Prentice Hall Voyage of the Beagle During his travels, Darwin made numerous observations and collected evidence that led him to propose a hypothesis about the way life changes over time. That hypothesis has become the theory of evolution.

8. 15-1 The Puzzle of Life's Diversity Slide 8 of 20 Copyright Pearson Prentice Hall Darwin's Observations Darwin observed that many plants and animals were well suited to the environments they inhabited. He was impressed by the ways in which organisms survived and produced offspring.

9. 15-1 The Puzzle of Life's Diversity Slide 9 of 20 Copyright Pearson Prentice Hall Darwin's Observations Darwin was puzzled by where different species lived and did not live. Grasslands in some regions were similar to one another but were inhabited by very different animals.

10. 15-1 The Puzzle of Life's Diversity Slide 10 of 20 Copyright Pearson Prentice Hall Darwin's Observations Living Organisms and Fossils Darwin collected the preserved remains of ancient organisms, called fossils. Some of those fossils resembled organisms that were still alive. Others looked completely unlike any creature he had ever seen.

11. 15-1 The Puzzle of Life's Diversity Slide 11 of 20 Copyright Pearson Prentice Hall Darwin's Observations The Galápagos Islands Darwin observed that the Galápagos Islands were close together but had very different climates. The Beagle was in the Galapagos for five weeks, from 15 September to 20 October 1835, and made a series of charts which were still in use by mariners in the 1940s. Darwin landed at only four of the islands (San Cristobal, Floreana, Santiago, and Isabela); his wonder would have been all the greater had he visited other islands, for the same pattern is repeated throughout the archipelago.

12. 15-1 The Puzzle of Life's Diversity Slide 12 of 20 Copyright Pearson Prentice Hall The Journey Home What pattern did Darwin observe among organisms of the Galápagos Islands?

13. 15-1 The Puzzle of Life's Diversity Slide 13 of 20 Copyright Pearson Prentice Hall The Journey Home Darwin observed that the characteristics of many animals and plants varied noticeably among the different islands of the Galápagos.

14. 15-1 The Puzzle of Life's Diversity Slide 14 of 20 Copyright Pearson Prentice Hall The Journey Home Darwin wondered if animals living on different islands had once been members of the same species. These separate species would have evolved from an original South American ancestor species. In 1837, a year after the return of H.M.S. Beagle, Darwin started to formulate his thoughts on the idea of evolution. In March, he was told by the ornithologist John Gould that the finches found on seven islands of Galapagos differed from one another on a specific level. At this point, Darwin was finally sure that geological separation played a very important part in the formation of new species: in different environments, species changed gradually over time in different ways to adapt to the local environment.

15. - or - Continue to: Click to Launch: Slide 15 of 20 Copyright Pearson Prentice Hall 15-1

16. Slide 16 of 20 Copyright Pearson Prentice Hall 15-1 Darwin's observations in the Galápagos Islands included all of the following EXCEPT a.characteristics of many living organisms did not vary among the different Galápagos Islands. b.many plants and animals were well suited to their environments. c.very different animals inhabited many similar ecosystems. d.though close together, the islands had very different climates.

17. Slide 17 of 20 Copyright Pearson Prentice Hall 15-1 What did Darwin learn about the tortoises of the Galápagos Islands? a.Tortoises with dome-shaped shells were found on all of the islands. b.The tortoises resembled fossil remains that were found on the islands. c.The shape of the Galápagos tortoise shells varied with their different habitats. d.Different shaped tortoise shells occupied the same habitats.

18. Slide 18 of 20 Copyright Pearson Prentice Hall 15-1 According to Darwin's proposed theory of evolution, species of organisms a.change over time. b.are not related to fossil remains. c.do not vary from one location to another. d.remain unchanged when the environment changes.

19. Slide 19 of 20 Copyright Pearson Prentice Hall 15-1 Darwin hypothesized that different-looking mockingbirds from different islands might be descendants of birds that a.belonged to a single species that had originated on the islands. b.belonged to a single species from the South American mainland. c.belonged to a different species from similar habitats in South America. d.had been brought to the islands by earlier visitors.

20. Slide 20 of 20 Copyright Pearson Prentice Hall 15-1 What role did the evidence gathered by Darwin play in developing his ideas? a.It immediately gave him the idea that organisms evolved. b.It confirmed evolution—an idea he had before he left England. c.It confirmed evolution, which he proved on his arrival in the Galápagos. d.It led to considering the possibility of evolution only after he was heading home.

21. END OF SECTION

22. Slide 22 of 27 Copyright Pearson Prentice Hall Biology

23. Slide 23 of 27 Copyright Pearson Prentice Hall 15–2 Ideas That Shaped Darwin's Thinking

24. 15–2 Ideas That Shaped Darwin's Thinking Slide 24 of 27 Copyright Pearson Prentice Hall An Ancient, Changing Earth How did Hutton and Lyell describe geological change?

25. 15–2 Ideas That Shaped Darwin's Thinking Slide 25 of 27 Copyright Pearson Prentice Hall An Ancient, Changing Earth Hutton and Lyell helped scientists recognize that Earth is many millions of years old, and the processes that changed Earth in the past are the same processes that operate in the present.

26. 15–2 Ideas That Shaped Darwin's Thinking Slide 26 of 27 Copyright Pearson Prentice Hall An Ancient, Changing Earth Hutton and Geological Change In 1795, James Hutton published a hypothesis about the geological forces that shaped Earth. Most of these geological forces operate very slowly, over millions of years. Hutton proposed that Earth had to be much more than a few thousand years old.

27. 15–2 Ideas That Shaped Darwin's Thinking Slide 27 of 27 Copyright Pearson Prentice Hall An Ancient, Changing Earth Lyell's Principles of Geology Lyell stressed that scientists must explain past events in terms of processes that they can actually observe. The processes that shaped the Earth millions of years earlier continue in the present.

28. 15–2 Ideas That Shaped Darwin's Thinking Slide 28 of 27 Copyright Pearson Prentice Hall An Ancient, Changing Earth Lyell’s work explained how geological features could be built up or torn down over long periods of time.

29. 15–2 Ideas That Shaped Darwin's Thinking Slide 29 of 27 Copyright Pearson Prentice Hall An Ancient, Changing Earth This understanding of geology influenced Darwin: If the Earth could change over time, life might change as well. It would have taken many years for life to change in the way Lyell suggested. This would have been possible only if the Earth were extremely old.

30. 15–2 Ideas That Shaped Darwin's Thinking Slide 30 of 27 Copyright Pearson Prentice Hall Lamarck’s Evolution Hypotheses According to Lamarck, how did species evolve?

31. 15–2 Ideas That Shaped Darwin's Thinking Slide 31 of 27 Copyright Pearson Prentice Hall Lamarck's Evolution Hypotheses Jean-Baptiste Lamarck recognized that: living things have changed over time. all species were descended from other species. organisms were adapted to their environments.

32. 15–2 Ideas That Shaped Darwin's Thinking Slide 32 of 27 Copyright Pearson Prentice Hall Lamarck's Evolution Hypotheses Lamarck proposed that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime. These traits could then be passed on to their offspring. Over time, this process led to change in a species.

33. 15–2 Ideas That Shaped Darwin's Thinking Slide 33 of 27 Copyright Pearson Prentice Hall Lamarck's Evolution Hypotheses Tendency Toward Perfection Lamarck proposed that all organisms have an innate tendency toward complexity and perfection. They are continually changing and acquiring features that help them live more successfully in their environments.

34. 15–2 Ideas That Shaped Darwin's Thinking Slide 34 of 27 Copyright Pearson Prentice Hall Lamarck's Evolution Hypotheses Use and Disuse Lamarck proposed that organisms could alter the size or shape of particular organs by using their bodies in new ways.

35. 15–2 Ideas That Shaped Darwin's Thinking Slide 35 of 27 Copyright Pearson Prentice Hall Lamarck's Evolution Hypotheses Lamarck's Hypothesis A male fiddler crab uses its front claw to ward off predators and to attract mates.

36. 15–2 Ideas That Shaped Darwin's Thinking Slide 36 of 27 Copyright Pearson Prentice Hall Lamarck's Evolution Hypotheses Lamarck's Hypothesis Because the front claw is used repeatedly, it becomes larger. This characteristic (large claw) is passed onto its offspring.

37. 15–2 Ideas That Shaped Darwin's Thinking Slide 37 of 27 Copyright Pearson Prentice Hall Lamarck's Evolution Hypotheses Inheritance of Acquired Traits Lamarck thought that acquired characteristics could be inherited. He believed that if an animal acquired a particular feature in its lifetime, that feature would be passed on to its offspring.

38. 15–2 Ideas That Shaped Darwin's Thinking Slide 38 of 27 Copyright Pearson Prentice Hall Lamarck's Evolution Hypotheses Evaluating Lamarck's Hypotheses Lamarck’s hypotheses of evolution are incorrect in several ways. Lamarck did not know: how traits are inherited. that an organism’s behavior has no effect on its heritable characteristics. However, he paved the way for the work of later biologists.

39. 15–2 Ideas That Shaped Darwin's Thinking Slide 39 of 27 Copyright Pearson Prentice Hall Population Growth What was Malthus's theory of population growth?

40. 15–2 Ideas That Shaped Darwin's Thinking Slide 40 of 27 Copyright Pearson Prentice Hall Population Growth In 1798, Thomas Malthus published a book in which he noted that babies were being born faster than people were dying. The only forces he observed that worked against this growth were war, famine, and disease.

41. 15–2 Ideas That Shaped Darwin's Thinking Slide 41 of 27 Copyright Pearson Prentice Hall Population Growth Malthus reasoned that if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone.

42. 15–2 Ideas That Shaped Darwin's Thinking Slide 42 of 27 Copyright Pearson Prentice Hall Population Growth When Darwin read Malthus’s work, he realized that this reasoning applied to plants and animals. If all the offspring of almost any species survived for several generations, they would overrun the world. This information was central to Darwin’s explanation of evolutionary change.

43. - or - Continue to: Click to Launch: Slide 43 of 27 Copyright Pearson Prentice Hall 15–2

44. Slide 44 of 27 Copyright Pearson Prentice Hall 15–2 Hutton and Lyell recognized that geological processes a.of the past differ from those of the present. b.indicate that Earth is many millions of years old. c.operate quickly, often over thousands of years. d.always involve violent events like volcanoes, earthquakes, and floods.

45. Slide 45 of 27 Copyright Pearson Prentice Hall 15–2 The discovery of many fossils challenged the idea that a.acquired traits could be inherited. b.Earth is many millions of years old. c.species had never changed over time. d.geological changes are slow.

46. Slide 46 of 27 Copyright Pearson Prentice Hall 15–2 Which of the following scientists proposed the hypothesis of selective use and disuse? a.Charles Darwin b.Jean-Baptiste Lamarck c.Thomas Malthus d.Charles Lyell

47. Slide 47 of 27 Copyright Pearson Prentice Hall 15–2 The scientist that proposed that Earth is shaped by geological forces that took place over long periods of time is: a.Malthus b.Hutton c.Darwin d.Lamarck

48. Slide 48 of 27 Copyright Pearson Prentice Hall 15–2 Darwin’s reading of Thomas Malthus made him realize that a.because of overpopulation, human beings cannot avoid extinction. b.all living things must evolve. c.living things produce more offspring than can possibly survive. d.the basic ideas of Lamarck were wrong.

49. END OF SECTION

50. Slide 50 of 41 Copyright Pearson Prentice Hall Biology

51. Slide 51 of 41 Copyright Pearson Prentice Hall 15-3 Darwin Presents His Case

52. Slide 52 of 41 Copyright Pearson Prentice Hall Publication of On the Origin of Species Darwin filled notebooks with his ideas about species diversity and the evolution process. Darwin was stunned and disturbed by his discoveries. He shelved his manuscript for years and told his wife to publish it in case he died.

53. 15-3 Darwin Presents His Case Slide 53 of 41 Copyright Pearson Prentice Hall Publication of On the Origin of Species In 1858, Darwin received a short essay from naturalist Alfred Wallace. The essay summarized Darwin’s thoughts on evolutionary change. Later that year, Wallace’s essay was presented with some of Darwin’s work. In 1859, Darwin published his book, On the Origin of Species.

54. 15-3 Darwin Presents His Case Slide 54 of 41 Copyright Pearson Prentice Hall Publication of On the Origin of Species In his book, Darwin: proposed a mechanism for evolution called natural selection. presented evidence that evolution has been taking place for millions of years—and continues in all living things.

55. 15-3 Darwin Presents His Case Slide 55 of 41 Copyright Pearson Prentice Hall Inherited Variation and Artificial Selection Members of each species vary from one another in important ways. In Darwin’s day, variations were thought to be unimportant, minor defects. Darwin argued that this variation mattered.

56. 15-3 Darwin Presents His Case Slide 56 of 41 Copyright Pearson Prentice Hall Inherited Variation and Artificial Selection Darwin noted that plant and animal breeders would breed only the largest hogs, the fastest horses, or the cows that produced the most milk. Darwin termed this process artificial selection.

57. 15-3 Darwin Presents His Case Slide 57 of 41 Copyright Pearson Prentice Hall Inherited Variation and Artificial Selection How is natural variation used in artificial selection?

58. 15-3 Darwin Presents His Case Slide 58 of 41 Copyright Pearson Prentice Hall Inherited Variation and Artificial Selection Artificial selection is the selection by humans for breeding of useful traits from the natural variation among different organisms.

59. 15-3 Darwin Presents His Case Slide 59 of 41 Copyright Pearson Prentice Hall Inherited Variation and Artificial Selection Brussels Sprouts Kohlrabi Ancestral Species Kale Broccoli Cauliflower

60. 15-3 Darwin Presents His Case Slide 60 of 41 Copyright Pearson Prentice Hall Evolution by Natural Selection Darwin compared processes in nature to artificial selection. By doing so, he developed a scientific hypothesis to explain how evolution occurs.

61. 15-3 Darwin Presents His Case Slide 61 of 41 Copyright Pearson Prentice Hall Evolution by Natural Selection The Struggle for Existence Darwin realized that high birth rates and a shortage of life's basic needs would force organisms to compete for resources.

62. 15-3 Darwin Presents His Case Slide 62 of 41 Copyright Pearson Prentice Hall Evolution by Natural Selection The struggle for existence means that members of each species compete regularly to obtain food, living space, and other necessities of life. The struggle for existence was central to Darwin's theory of evolution.

63. 15-3 Darwin Presents His Case Slide 63 of 41 Copyright Pearson Prentice Hall Evolution by Natural Selection How is natural selection related to a species' fitness?

64. 15-3 Darwin Presents His Case Slide 64 of 41 Copyright Pearson Prentice Hall Evolution by Natural Selection Survival of the Fittest The ability of an individual to survive and reproduce in its specific environment is fitness. Darwin proposed that fitness is the result of adaptations. An adaptation is any inherited characteristic that increases an organism's chance of survival.

65. 15-3 Darwin Presents His Case Slide 65 of 41 Copyright Pearson Prentice Hall Evolution by Natural Selection Successful adaptations enable organisms to become better suited to their environment and better able to survive and reproduce.

66. 15-3 Darwin Presents His Case Slide 66 of 41 Copyright Pearson Prentice Hall Evolution by Natural Selection Individuals with characteristics that are not well suited to their environment either die or leave few offspring. Individuals that are better suited to their environment survive and reproduce most successfully. Darwin called this process survival of the fittest.

67. 15-3 Darwin Presents His Case Slide 67 of 41 Copyright Pearson Prentice Hall Evolution by Natural Selection Because of its similarities to artificial selection, Darwin referred to the survival of the fittest as natural selection. In natural selection, the traits being selected contribute to an organism's fitness in its environment.

68. 15-3 Darwin Presents His Case Slide 68 of 41 Copyright Pearson Prentice Hall Evolution by Natural Selection Over time, natural selection results in changes in the inherited characteristics of a population. These changes increase a species' fitness in its environment.

69. 15-3 Darwin Presents His Case Slide 69 of 41 Copyright Pearson Prentice Hall Evolution by Natural Selection Descent With Modification Natural selection produces organisms that have different structures, establish different niches, or occupy different habitats. Each living species has descended, with changes, from other species over time. Darwin referred to this principle as descent with modification.

70. 15-3 Darwin Presents His Case Slide 70 of 41 Copyright Pearson Prentice Hall Evolution by Natural Selection Descent with modification implies that all living organisms are related to one another. This is the principle known as common descent.

71. 15-3 Darwin Presents His Case Slide 71 of 41 Copyright Pearson Prentice Hall Evidence of Evolution What evidence of evolution did Darwin present?

72. 15-3 Darwin Presents His Case Slide 72 of 41 Copyright Pearson Prentice Hall Evidence of Evolution Darwin argued that living things have been evolving on Earth for millions of years. Evidence for this process could be found in the fossil record, the geographical distribution of living species, homologous structures of living organisms, and similarities in early development, or embryology.

73. 15-3 Darwin Presents His Case Slide 73 of 41 Copyright Pearson Prentice Hall Evidence of Evolution The Fossil Record Darwin saw fossils as a record of the history of life on Earth. By comparing fossils from older rock layers with fossils from younger layers, scientists could document that life on Earth has changed over time.

74. 15-3 Darwin Presents His Case Slide 74 of 41 Copyright Pearson Prentice Hall Evidence of Evolution Geographic Distribution of Living Species Darwin decided that all Galápagos finches could have descended with modification from a common mainland ancestor. Darwin’s theory was that species now living on different continents had each descended from different ancestors.

75. 15-3 Darwin Presents His Case Slide 75 of 41 Copyright Pearson Prentice Hall Evidence of Evolution However, because some animals on each continent were living under similar ecological conditions, they were exposed to similar pressures of natural selection. Because of these similar selection pressures, different animals ended up evolving certain features in common.

76. 15-3 Darwin Presents His Case Slide 76 of 41 Copyright Pearson Prentice Hall Evidence of Evolution Similar, But Unrelated Species and

77. 15-3 Darwin Presents His Case Slide 77 of 41 Copyright Pearson Prentice Hall Evidence of Evolution Homologous Body Structures Structures that have different mature forms but develop from the same embryonic tissues are called homologous structures. Similarities and differences in homologous structures help biologists group animals according to how recently they last shared a common ancestor.

78. 15-3 Darwin Presents His Case Slide 78 of 41 Copyright Pearson Prentice Hall Evidence of Evolution Homologous Structures Turtle Alligator Bird Mammal Ancient, lobe- finned fish

79. 15-3 Darwin Presents His Case Slide 79 of 41 Copyright Pearson Prentice Hall Evidence of Evolution Not all homologous structures serve important functions. The organs of many animals are so reduced in size that they are just vestiges, or traces, of homologous organs in other species. These organs are called vestigial organs.

80. 15-3 Darwin Presents His Case Slide 80 of 41 Copyright Pearson Prentice Hall Evidence of Evolution Similarities in Embryology The early stages, or embryos, of many animals with backbones are very similar. The same groups of embryonic cells develop in the same order and in similar patterns to produce the tissues and organs of all vertebrates.

81. 15-3 Darwin Presents His Case Slide 81 of 41 Copyright Pearson Prentice Hall Summary of Darwin's Theory Individual organisms differ, and some of this variation is heritable. Organisms produce more offspring than can survive, and many that do survive do not reproduce. Because more organisms are produced than can survive, they compete for limited resources.

82. 15-3 Darwin Presents His Case Slide 82 of 41 Copyright Pearson Prentice Hall Summary of Darwin's Theory Individuals best suited to their environment survive and reproduce most successfully. These organisms pass their heritable traits to their offspring. Other individuals die or leave fewer offspring. This process of natural selection causes species to change over time.

83. 15-3 Darwin Presents His Case Slide 83 of 41 Copyright Pearson Prentice Hall Summary of Darwin's Theory Species alive today are descended with modification from ancestral species that lived in the distant past. This process, by which diverse species evolved from common ancestors, unites all organisms on Earth into a single tree of life.

84. 15-3 Darwin Presents His Case Slide 84 of 41 Copyright Pearson Prentice Hall Strengths and Weaknesses of Evolutionary Theory Scientific advances in many fields of biology, geology, and physics have confirmed and expanded most of Darwin’s hypotheses. Evolutionary theory continues to change as new data are gathered and new ways of thinking arise.

85. - or - Continue to: Click to Launch: Slide 85 of 41 Copyright Pearson Prentice Hall 15-3

86. Slide 86 of 41 Copyright Pearson Prentice Hall 15-3 The scientist who motivated Darwin to publish On the Origin of Species was a.Alfred Russel Wallace. b.Charles Lyell. c.Jean-Baptiste Lamarck. d.Thomas Malthus.

87. Slide 87 of 41 Copyright Pearson Prentice Hall 15-3 Differences among individuals of a single species are referred to as a.artificial selection. b.genetic variation. c.survival of the fittest. d.environmental adaptation.

88. Slide 88 of 41 Copyright Pearson Prentice Hall 15-3 Changes that increase a species' fitness in its environment over time are due to a.the principle of common descent. b.the geographic distribution of that species. c.natural selection. d.habitat selection.

89. Slide 89 of 41 Copyright Pearson Prentice Hall 15-3 An inherited characteristic that increases an organism's chance of survival is called a(an) a.homologous structure. b.vestigial organ. c.adaptation. d.analogous structure.

90. Slide 90 of 41 Copyright Pearson Prentice Hall 15-3 Evidence used by Darwin to support the idea of evolution included all the following EXCEPT a.fossils that demonstrate change over time. b.the genetic mechanism by which useful traits are inherited. c.the geographic distribution of living things. d.the presence of many homologous structures in plants and animals.

91. END OF SECTION