CHAPTER 18 STUDY GUIDE FOR EXAM

CHAPTER 18 STUDY GUIDE FOR EXAM Multiple Choice Identify the choice that best completes the statement or answers the question. 1. The primary reason that dragonflies grew so much larger 300 million years ago than they do today is that a. they lacked predators then. b. they were able to exploit an aquatic niche that no longer exists. c. there was more oxygen in the air then. d. there was more nitrogen in the air then. e. Earth was much colder then. 2. The first person to realize that the relative ages of rocks can be determined by examining strata was a. Charles Darwin. b. Alfred Russel Wallace. c. Stephen Jay Gould. d. Nicolaus Steno. e. Alfred Wegener. 3. Which of the following geological periods is the most recent (closest to the present)? a. Devonian b. Cambrian c. Jurassic d. Silurian e. Cretaceous 4. Which of the following geological periods is the most ancient? a. Devonian b. Cambrian c. Jurassic d. Silurian e. Cretaceous 5. Fossils that are one hundred million years old date from the period. a. Devonian b. Cambrian c. Jurassic d. Silurian e. Cretaceous 6. Which of the following represents a correct chronological ordering of Earth s geological history, from the most ancient to the most recent period? a. Cambrian, Cretaceous, Devonian, Permian b. Cretaceous, Devonian, Permian, Cambrian c. Cambrian, Devonian, Permian, Cretaceous d. Permian, Cambrian, Cretaceous, Devonian e. Cretaceous, Permian, Devonian, Cambrian 7. Which of the following statements about radiometric dating is true? a. Radioactive decay of 14 C is balanced by its production from neutrons reacting with 14 N in the upper atmosphere. b. Dead organisms continue to exchange carbon compounds with the environment. c. Carbon dating can be used to date organisms more than a million years old. d. The half-life of 14 C is less than 1,000 years. 8. If the half-life of a radioactive substance is 600 years, what fraction of the original material is left after 1,800 years? a. One-half b. One-fourth c. One-eighth d. One-sixteenth 9. The half-life of carbon-14 is 5,700 years. If 10 percent of the original carbon-14 is left in a structure, that structure is years old. a. less than 2,850 b. about 5,700 c. between 11,400 and 17,100 d. between 17,100 and 22,800

10. Which of the following would be possible to date by means of radioactive carbon? a. A mastodon that is about 15,000 years old b. Remains thought to be associated with King Tut (who lived 2,500 years ago) c. A Homo erectus skeleton thought be around 800,000 years old d. Both a and b 11. In the upper atmosphere, the bombardment of neutrons with nitrogen-14 varies somewhat over time. If in the past this rate had been higher, objects dated by dating would now appear than they really are. a. potassium; younger b. potassium; older c. carbon; younger d. carbon; older e. uranium; younger 12. Which of the following statements about geological dating is false? a. The isotopes in sedimentary rocks contain reliable information about the dates of their formation. b. Igneous rocks are formed when molten material cools. c. The decay of potassium-40 to argon-40 has been used to date most of the ancient events in the evolution of life. d. Paleomagnetic dating relates the ages of rocks to patterns in Earth s magnetism. e. All of the above are true; none is false. 13. The first person to put forth the idea that Earth s continents are in continual but slow motion was a. Charles Darwin. b. Alfred Russel Wallace. c. Stephen Jay Gould. d. Nicolaus Steno. e. Alfred Wegener. 14. Suppose you were to drill a hole toward the center of Earth. Which of the following is the correct order of the layers you would encounter? a. Magma, mantle, lithospheric plate b. Mantle, magma, lithospheric plate c. Lithospheric plate, magma, mantle d. Lithospheric plate, mantle, magma e. Mantle, lithospheric plate, magma 15. Which of the following statements about continental drift is true? a. When it was proposed, the idea received almost immediate acceptance. b. Continents move because rising magma exerts tremendous pressure on the plates that float on top of it. c. Deep rift valleys have been generated from the same process that causes continental drift. d. Both a and b e. Both b and c 16. The heat that drives plate tectonics is driven by a. radiant energy from the sun. b. chemical energy from bacteria. c. chemical energy from inorganic enzymatic cycles. d. radioactive decay inside Earth s crust. e. kinetic energy from meteorite collisions. 17. Which of the following leads to the formation of mountain ranges? a. The mantle pushing against a lithospheric plate b. Lithospheric plates moving sideways past one another c. One lithospheric plate sliding under another d. Magma pushing plates apart 18. Near the ends of several geological periods, including the Devonian, Permian, and the Triassic, sea level dramatically, most likely due to. a. rose; increased glaciation b. rose; decreased glaciation c. rose; cessation of continental drift

d. fell; increased glaciation e. fell; cessation of continental drift 19. Which of the following is not considered a plausible hypothesis for the causes of mass extinctions? a. Extraterrestrial events, such as meteorite or asteroid collisions b. Glaciations c. Massive volcanic activity d. Competition among organisms e. All of the above are considered plausible hypotheses. 20. Which of the following gases has substantially increased in concentration in the last 200 years? a. Oxygen b. Carbon dioxide c. Nitrogen d. Argon e. Hydrogen 21. Which of the following gases have opposite effects on Earth s climate? a. Nitrogen and oxygen b. Nitrogen and carbon dioxide c. Carbon dioxide and sulfur dioxide d. Carbon dioxide and oxygen 22. Observations from Krakatau and Mt. Pinatubo a. provide evidence for mass extinctions caused by extraterrestrial events. b. challenge the notion that extraterrestrial events can cause mass extinctions. c. demonstrate that volcanic activity can increase global temperatures. d. demonstrate that volcanic activity can decrease global temperatures. 23. Supporting the claim that a meteorite caused the mass extinction at the end of the Cretaceous period, abnormally high concentrations of have been found in rocks dating from that time. a. lithium b. iridium c. mercury d. nickel e. tungsten 24. The possible collision of a large meteorite with Earth 65 million years ago may explain a. the existence of Gondwana. b. continental drift, according to Alfred Wegener. c. the mass extinction that killed off the dinosaurs. d. contemporary atmospheric conditions on Earth. 25. Which continent was most likely affected the most by the meteor strike that led to the demise of non-avian dinosaurs? a. Asia b. Europe c. Africa d. Australia e. North America 26. Which of the following statements about oxygen and ancient Earth is true? a. The atmosphere of early Earth contained almost as much free oxygen as present-day Earth, but most of this oxygen was lost in the Cambrian. b. Early bacteria generated free oxygen as a by-product of the chemical splitting of water. c. The oxygen-generating cyanobacteria have gone extinct. d. All of the above

27. Rocklike structures formed by the oxygen-generating cyanobacteria are known as a. strata. b. stromatolites. c. igneous rocks. d. lithospheres. e. rift valleys. 28. Which of the following statements about the early history of life on Earth is false? a. The evolution of life changed the physical nature of Earth. b. Changes in the physical nature of Earth affected the evolution of early life forms. c. Early bacteria generated oxygen as a waste product of chemical reactions that split water molecules. d. Symbiosis of bacteria with eukaryotic cells led to increased oxygen concentrations. e. All of the above are true; none is false. 29. As compared to anaerobic metabolism, aerobic metabolism is advantageous to cells because it a. proceeds at a more rapid rate. b. is more efficient. c. permits the growth of larger, more complex cells. d. All of the above 30. The appearance of multicellular organisms coincided with increased levels of in Earth s atmosphere. a. sulfur b. hydrogen c. nitrogen d. carbon e. oxygen 31. At normal levels of oxygen, selection is for body size in Drosophila. At higher levels of oxygen, the flies experience selection. a. stabilizing; directional b. stabilizing; disruptive c. directional; stabilizing d. directional; disruptive e. disruptive; stabilizing 32. Approximately fossil species have been described. a. 3,000 b. 30,000 c. 150,000 d. 1.7 million e. 10 million 33. All of the plants living at a particular time or place are called its a. biota. b. flora. c. fauna. d. igneous species. e. Gondwana. 34. Which of the following conditions would increase the likelihood of an animal s being fossilized? a. Living in an oxygen-rich environment b. Having an exoskeleton c. Living in an area where geological processes often transform rocks d. Both a and b 35. The period of time between life s first appearance on Earth and the definite appearance of multicellular life was about years. a. 200 million b. 500 million c. 1 billion d. 3 billion e. 4.5 billion 36. In the late Precambrian, the first evolved. a. vascular plants b. multicellular eukaryotes c. jawed fish d. photosynthetic bacteria

e. insects 37. The Cambrian explosion started the Cambrian and lasted 42. Fishlike amphibians began to occupy land during the for of years. a. Cretaceous. a. before; tens of thousands b. Cambrian. b. before; millions c. Devonian. c. during; hundreds d. Silurian. d. during; tens of thousands e. Holocene. e. during; millions 43. The first flying animals were, which first appeared in the 38. Which of the following statements about the Cambrian is true? period. a. The Burgess Shale is a Cambrian fossil bed. a. birds; Carboniferous b. The first multicellular life occurred during the Cambrian. b. birds; Cretaceous c. The Cambrian marks the end of the Paleozoic era. c. bats; Jurassic d. Oxygen concentrations were much lower during the Cambrian d. insects; Carboniferous than they are today. e. insects; Permian 44. Vertebrates whose well-protected eggs that can withstand a dry 39. Which of the following statements about the Cambrian is false? environment are known as a. Arthropods were abundant and diverse during this period. a. trilobites. b. There was abundant multicellular terrestrial life. b. ediacaran. c. Large continents had already formed. c. crinoides. d. Oxygen concentrations were approaching current levels. d. amniotes. e. All of the above are true; none is false. e. dinosaurs. 40. Which of the following statements about the Ordovician is false? 45. During the Permian period, all of the continents came together to a. In an undisturbed formation, fossils from this period will be form one supercontinent known as located directly above those from the Cambrian. a. Pangaea. b. There was a major extinction at the end of this period. b. Gondwana. c. This was a period of great diversification of marine life. c. Laurasia. d. The end of this period occurred less than 300 million years d. Crinoid. ago. e. Ork. e. All of the above are true; none is false. 46. Which of the following organisms would you not expect to see 41. Vascular plants first appeared during the during a walk in a Permian forest? a. Cambrian. a. Dragonflies b. Ordovician. b. Amphibians c. Silurian. c. Club mosses and horsetails d. Carboniferous. d. Flowering plants e. Permian. e. Gymnosperms

47. The most dramatic mass extinction in Earth s history, which destroyed about 96 percent of the species, 51. Which of the following statements about the mass extinction at a. killed off the dinosaurs. the end of the Cretaceous is false? b. occurred at the end of the Cretaceous. a. A meteorite was involved. c. occurred at the end of the Permian. b. Many marine invertebrates and insect species died out. d. Both a and b c. Almost all land animals larger than about 25 kilograms, e. Both a and c including dinosaurs, became extinct. 48. The Permian extinction occurred approximately million d. It was the largest mass extinction in Earth s history. years ago. e. All of the above are true; none is false. a. 40 52. The Cenozoic era began about years ago. b. 65 a. 1 million c. 150 b. 15 million d. 250 c. 65 million e. 550 d. 225 million 49. During which period did the following events occur: recovery of e. 1 billion the biota after a major mass extinction, increase in the species 53. The current geological period is the richness of invertebrate groups, appearance of the first turtles a. Tertiary. and frogs, and beginnings of a large radiation of reptiles? b. Quaternary. a. Permian c. Triassic. b. Cambrian d. Devonian. c. Jurassic e. Pleistocene. d. Cretaceous 54. Humans reached North America approximately years e. Triassic ago. 50. Which of the following represents the correct chronological order a. 500 of events, from earliest to latest? b. 1,500 a. 100 million years ago, first mammals appear, dinosaurs go c. 15,000 extinct d. 100,000 b. 100 million years ago, dinosaurs go extinct, first mammals e. 1 million appear c. Dinosaurs go extinct, first mammals appear, 100 million years ago d. First mammals appear, 100 million years ago, dinosaurs go extinct e. First mammals appear, dinosaurs go extinct, 100 million years ago

Figure 18-1 Refer to the diagram below showing the decay of a radioactive substance. 55. Refer to Figure 18-1. What is the half-life of this substance? a. 50,000 years b. 70,000 years c. 100,000 years d. 140,000 years e. 300,000 years Completion Complete each statement. 56. The layers of rocks, also known as, are often found in a chronological sequence, with the oldest rocks at the. 57. In an undisturbed formation, fossils from the Jurassic period are immediately below those from the period. 58. The time in which half of a certain amount of a radioactive substance decays is known as its. 59. It takes 14 days for half of the radioactive isotope phosophorous- 32 to decay. After days, one-eighth of the original quantity will be left. 60. The half-life of a radioactive substance is 47 years. If you start with 20 mg of the substance, will be left after 94 years. 61. If 50 mg of a radioactive substance becomes 12.5 mg in 2,600 years, the half-life of the substance is years. 62. Suppose the half-life of a radioactive isotope is 900 years. Of the total amount of that element assimilated by living organisms into their tissues, 0.002 percent consists of the radioactive isotope. If you were to find a skeleton of an organism that had 0.0005 percent of the element as the radioactive isotope, it would be estimated to be years old. 63. The dating method makes use of changes in patterns of Earth s magnetism to date rocks. 64. The study of the movement of major land masses, also known as, led to strong evidence for continental drift. 65. Heat generated in Earth s core results in currents in the magma. This process pushes the plates along with the land masses on top of them. 66. Volcanic activity releases the gas into the atmosphere, which can cause a in the global temperature. 67. The rapid climate change we are experiencing currently is mainly caused by the buildup of atmospheric. 68. Evidence that meteorites hit Earth at times of mass extinctions comes from the presence of, a metal that is rare on Earth but common in some meteorites. 69. A group of oxygen-generating bacteria called formed rocklike structures known as stromatolites.

70. The long time lag between the origin of life and the appearance of multicellular life was probably partly due to the lack of in the atmosphere for much of Earth s existence. 71. Experiments with Drosophila have demonstrated that an increase in atmospheric oxygen concentration leads to a selection for body size. 72. The entire composition of plants in a given locality is known as its. 73. One billion years ago, Earth was in the era. 74. Of the total time that life has been on Earth, the period beginning with the Cambrian and going up to the present constitutes approximately percent of the total. 75. Great evolutionary radiations of corals and shelled squidlike cephalopods occurred during the period. 76. The largest mass extinction event occurred at the end of the period, due at least in part to declines in the concentration of in the atmosphere. 77. In comparison to the total time that life has been on Earth, the proportion that has been since the Permian extinction is approximately percent. 78. The first period of the Mesozoic, called the, saw the breakup of the supercontinent. 79. The mass extinction responsible for the demise of the dinosaurs occurred at the end of the period. 80. During the most recent geological era, which is called the, certain plants such as formed symbioses with nitrogen-fixing bacteria. Short Answer Scenario 18-1 Suppose life is found on another planet and you are part of a team assigned to provide the relative ages of different assemblages of fossils: Hadley, Leverett, Northampton, Sunderland, and Ware. In location A, the Hadley assemblage is found below the Ware assemblage and above the Leverett assemblage. In location B, the Northampton assemblage is found above the Sunderland assemblage. In location C, Ware is found below Sunderland. In location D, Hadley is found below Ware. Assume that the rocks are undisturbed in all locations. 81. Refer to Scenario 18-1. Construct a diagram showing the relative positions of all five strata. 82. Refer to Scenario 18-1. Which assemblage is the oldest? Which is the youngest? 83. Refer to Scenario 18-1. Did you need the information in location D to determine the relative ages of all five strata? Explain.

CHAPTER 18 STUDY GUIDE FOR EXAM Answer Section MULTIPLE CHOICE 1. ANS: C PTS: 1 REF: Page 347 TOP: 18.0 Introduction 2. ANS: D PTS: 1 REF: Page 348 TOP: Concept 18.1 Events in Earth s History Can Be Dated 3. ANS: E PTS: 1 REF: Page 348 TOP: Concept 18.1 Events in Earth s History Can Be Dated 4. ANS: B PTS: 1 REF: Page 348 TOP: Concept 18.1 Events in Earth s History Can Be Dated 5. ANS: E PTS: 1 REF: Page 348 TOP: Concept 18.1 Events in Earth s History Can Be Dated 6. ANS: C PTS: 1 REF: Page 348 TOP: Concept 18.1 Events in Earth s History Can Be Dated 7. ANS: A PTS: 1 REF: Page 349 TOP: Concept 18.1 Events in Earth s History Can Be Dated 8. ANS: C PTS: 1 REF: Page 349 TOP: Concept 18.1 Events in Earth s History Can Be Dated 9. ANS: D PTS: 1 REF: Page 349 TOP: Concept 18.1 Events in Earth s History Can Be Dated 10. ANS: D PTS: 1 REF: Page 349 TOP: Concept 18.1 Events in Earth s History Can Be Dated SKL: 4. Analyzing 11. ANS: C PTS: 1 REF: Page 349 TOP: Concept 18.1 Events in Earth s History Can Be Dated SKL: 5. Evaluating 12. ANS: A PTS: 1 REF: Page 349-350 TOP: Concept 18.1 Events in Earth s History Can Be Dated 13. ANS: E PTS: 1 REF: Page 351 14. ANS: C PTS: 1 REF: Page 351 15. ANS: E PTS: 1 REF: Page 351 16. ANS: D PTS: 1 REF: Page 351 17. ANS: C PTS: 1 REF: Page 351 18. ANS: D PTS: 1 REF: Page 351

19. ANS: D PTS: 1 REF: Page 352 20. ANS: B PTS: 1 REF: Page 352 21. ANS: C PTS: 1 REF: Page 352 SKL: 4. Analyzing 22. ANS: D PTS: 1 REF: Page 352 23. ANS: B PTS: 1 REF: Page 353 24. ANS: C PTS: 1 REF: Page 353 25. ANS: E PTS: 1 REF: Page 353 26. ANS: B PTS: 1 REF: Page 353-354 27. ANS: B PTS: 1 REF: Page 354 28. ANS: E PTS: 1 REF: Page 354 29. ANS: D PTS: 1 REF: Page 354 30. ANS: E PTS: 1 REF: Page 354 31. ANS: A PTS: 1 REF: Page 355 32. ANS: C PTS: 1 REF: Page 356 33. ANS: B PTS: 1 REF: Page 356 34. ANS: B PTS: 1 REF: Page 356

35. ANS: D PTS: 1 REF: Page 357 36. ANS: B PTS: 1 REF: Page 357 37. ANS: B PTS: 1 REF: Page 358 38. ANS: A PTS: 1 REF: Page 358 39. ANS: B PTS: 1 REF: Page 358 40. ANS: D PTS: 1 REF: Page 358-359 41. ANS: C PTS: 1 REF: Page 358-359 42. ANS: C PTS: 1 REF: Page 358-359 43. ANS: D PTS: 1 REF: Page 358-360 44. ANS: D PTS: 1 REF: Page 360-362 45. ANS: A PTS: 1 REF: Page 360-362 46. ANS: D PTS: 1 REF: Page 360-362 47. ANS: C PTS: 1 REF: Page 360-362 48. ANS: D PTS: 1 REF: Page 360-362 49. ANS: E PTS: 1 REF: Page 360-362 50. ANS: D PTS: 1 REF: Page 360-362 51. ANS: D PTS: 1 REF: Page 362

52. ANS: C PTS: 1 REF: Page 363 53. ANS: B PTS: 1 REF: Page 363 54. ANS: C PTS: 1 REF: Page 363 55. ANS: D PTS: 1 REF: Page 349 TOP: Concept 18.1 Events in Earth s History Can Be Dated COMPLETION 56. ANS: strata, bottom PTS: 1 REF: Page 348 TOP: Concept 18.1 Events in Earth s History Can Be Dated 57. ANS: Cretaceous PTS: 1 REF: Page 348 TOP: Concept 18.1 Events in Earth s History Can Be Dated 58. ANS: half-life PTS: 1 REF: Page 349 TOP: Concept 18.1 Events in Earth s History Can Be Dated 59. ANS: 42 PTS: 1 REF: Page 349 TOP: Concept 18.1 Events in Earth s History Can Be Dated 60. ANS: 5 mg PTS: 1 REF: Page 349 TOP: Concept 18.1 Events in Earth s History Can Be Dated 61. ANS: 1,300 PTS: 1 REF: Page 349 TOP: Concept 18.1 Events in Earth s History Can Be Dated 62. ANS: 1,800 PTS: 1 REF: Page 349 TOP: Concept 18.1 Events in Earth s History Can Be Dated 63. ANS: paleomagnetic PTS: 1 REF: Page 350 TOP: Concept 18.1 Events in Earth s History Can Be Dated 64. ANS: plate tectonics

PTS: 1 REF: Page 351 65. ANS: convection, lithospheric PTS: 1 REF: Page 351 66. ANS: sulfur dioxide, decrease sulfur dioxide, decline sulfur dioxide, drop sulfur dioxide, reduction PTS: 1 REF: Page 352 67. ANS: carbon dioxide PTS: 1 REF: Page 352 68. ANS: iridium PTS: 1 REF: Page 353 69. ANS: cyanobacteria PTS: 1 REF: Page 354 70. ANS: oxygen PTS: 1 REF: Page 354 71. ANS: directional, larger PTS: 1 REF: Page 355 72. ANS: flora PTS: 1 REF: Page 356 73. ANS: Precambrian

PTS: 1 REF: Page 357 74. ANS: 14 PTS: 1 REF: Page 357 75. ANS: Devonian PTS: 1 REF: Page 358-359 76. ANS: Permian, oxygen PTS: 1 REF: Page 360-362 77. ANS: 6.5 PTS: 1 REF: Page 362 78. ANS: Triassic, Pangaea PTS: 1 REF: Page 362 79. ANS: Cretaceous PTS: 1 REF: Page 362 80. ANS: Cenozoic, legumes PTS: 1 REF: Page 363 SHORT ANSWER 81. ANS: Northampton should be on top, followed by Sunderland, then Ware, then Hadley, and finally Leverett on the bottom.

PTS: 1 REF: Page 348 TOP: Concept 18.1 Events in Earth s History Can Be Dated SKL: 6. Creating 82. ANS: Leverett is the oldest; Northampton is the youngest. PTS: 1 REF: Page 348 TOP: Concept 18.1 Events in Earth s History Can Be Dated 83. ANS: No. The information gathered from location D is a subset of what was gained from location A. Thus, it is not necessary. PTS: 1 REF: Page 348 TOP: Concept 18.1 Events in Earth s History Can Be Dated SKL: 4. Analyzing