Evolution. Name: Class: Date: Multiple Choice Identify the choice that best completes the statement or answers the question.

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1 Class: Date: Evolution Multiple Choice Identify the choice that best completes the statement or answers the question. 1. The primitive Earth atmosphere is hypothesized to have consisted mostly of. a. oxygen, nitrogen, and water vapor b. hydrogen, methane, ammonia, and water vapor c. amino acids, ATP, carbohydrates, and oxygen d. none of these 2. Since the 1950s, experiments have been conducted that lead scientists to conclude that life may have originated. a. spontaneously as originally thought b. in small pools of water where amino acids could be concentrated c. in other parts of the universe d. when prokaryotes joined together to make the first eukaryotic cell 3. Scientists agree that two developments must have occurred for life to come into being: the formation of simple organic molecules important to life and. a. development of prokaryotic cells in early oceans b. organization of molecules into complex organic molecules c. appearance of amino acids, monosaccharides, and lipids d. an atmosphere rich in water vapor, oxygen, and ATP 4. Before biogenesis became an accepted cornerstone of biology, it was widely accepted that. a. living things could arise spontaneously from other living things b. Francesco Redi and Louis Pasteur would be unable to test the current beliefs c. flies could be produced only from other flies d. maggots were the immature offspring of flies 5. Humans are thought to have evolved during the Era. a. Cenozoic c. Mesozoic b. Paleozoic d. Precambrian 6. The Geologic Time Scale begins at the formation of Earth approximately years ago. a. 4.6 thousand c. 46 million b. 4.6 million d. 4.6 billion 7. Which of the following statements are true about fossils? a. Fossils are usually found in sedimentary rock layers. b. There are many different ways that fossils can be formed. c. Fossil insects that were trapped in ice or hardened into amber. d. all of these 8. Which of the following fossils are not found in sedimentary rock? a. imprints c. amber b. frozen mammoths d. petrified wood 9. While looking for fossils on an eroded hillside, you discover fossil coral and fish in one layer. In a layer just above, you find the fossil imprint of a fern frond and some fossil moss. Assuming the rock has not been disturbed, which of the following is the most probable conclusion? a. The area had been a sea until recent times. b. A forest had once grown there but had become submerged by water. c. A sea had been replaced by land in ancient times. d. A saltwater sea had changed to a freshwater lake in ancient times. 4

2 10. According to one theory, the first prokaryotes probably obtained their food. a. through the synthesis of organic molecules from inorganic molecules b. through a combination of photosynthesis and aerobic respiration c. by eating carbohydrates formed by autotrophs d. by consuming organic molecules available in their environment 11. Which group of organisms is believed to have been the earliest to evolve? a. land plants c. aquatic dinosaurs b. cyanobacteria d. mammals 12. Which fact is the basis for using the fossil record as evidence that evolution has taken place? a. In undisturbed layers of rock strata, the older fossils are found in the deeper layers. b. There are fossils of all life-forms to be found in rock layers. c. All fossils were formed at the same time. d. Fossils have been shown to provide a complete record of human evolution. 13. A clear fish imprint in a rock indicates that the rock is probably. a. volcanic c. metamorphic b. sedimentary d. igneous 14. Urey and Miller subjected water, ammonia, methane, and hydrogen to heating and cooling cycles and jolts of electricity in an attempt to. a. determine how the dinosaurs became extinct b. form complex organic compounds c. determine the age of microfossils d. find out how ozone forms in the atmosphere 15. Which event contributed most directly to the evidence of aerobic organisms? a. an increase in the concentration of methane in the ancient atmosphere b. a decrease in the sun's light intensity c. the presence of organisms able to carry on photosynthesis d. an increase in the number of organisms carrying on fermentation Figure According to Figure 14-4, what was the earliest form of multicellular life on Earth? a. fish c. land plants b. invertebrates d. reptiles 2

3 17. According to Figure 14-4, the correct chronological order of organisms as they develop are. a. birds, dinosaurs, jawed fish, prokaryotes b. dinosaurs, jawed fish, birds, prokaryotes c. jawed fish, dinosaurs, prokaryotes, birds d. prokaryotes, jawed fish, dinosaurs, birds 18. According to Figure 14-4, in how many eras have mammals existed? a. 2 c. 5 b. 4 d Hawaiian honeycreepers are a group of birds with similar body shape and size. However, they vary greatly in color and beak shape. Each species occupies its own niche and is adapted to the foods available in its niche. The evolution from a common ancestor to a variety of species is an example of. a. divergent evolution c. vegetative propagation b. cross-pollination d. convergent evolution 20. The flying squirrel of North America closely resembles the flying phalanger of Australia. They are similar in size and have long, bushy tails and skin folds that allow them to glide through the air. The squirrel is a placental mammal, while the phalanger is a marsupial. These close resemblances, even though genetically and geographically separated by great distances, can best be explained by. a. convergent evolution c. spontaneous generation b. divergent evolution d. vestigial structures 21. Within a decade of the introduction of a new insecticide, nearly all of the descendants of the target pests were immune to the usual-sized dose. The most likely explanation for this immunity to the insecticide is that. a. eating the insecticide caused the bugs to become resistant to it b. eating the insecticide caused the bugs to become less resistant to it c. it destroyed organisms that cause disease in the insects, thus allowing them to live longer d. the pests developed physiological adaptations to the insecticide 22. Natural processes such as speciation and gradualism provide the genetic basis for. a. evolution c. biogenesis b. spontaneous generation d. sexual reproduction 23. Structures that have a similar evolutionary origin and structure but are adapted for different purposes, such as a bat wing and a human arm, are called. a. embryological structures c. homologous structures b. analogous structures d. homozygous structures 24. Natural selection can best be defined as the. a. survival of the biggest and strongest organisms in a population b. elimination of the smallest organisms by the biggest organisms c. survival and reproduction of the organisms that occupy the largest area d. survival and reproduction of the organisms that are genetically best adapted to the environment 25. A pattern of evolution that results when two unrelated species begin to appear similar because of environmental conditions is. a. disruptive selection c. directional selection b. convergent evolution d. divergent evolution 26. The average individuals of a population are favored in selection. a. directional c. disruptive b. stabilizing d. natural 3

4 27. In selection, individuals with both extreme forms of a trait are at a selective advantage. a. directional c. disruptive b. stabilizing d. natural 28. selection favors one extreme form of a trait in a population. a. Directional c. Disruptive b. Stabilizing d. Natural 29. What is the movement of genes into and out of a gene pool called? a. random mating c. gene flow b. nonrandom mating d. direct evolution 30. Which of the following lines of evidence for evolution is indirect? a. pesticide resistance c. fossils b. observed allele frequency changes d. all of these 31. Which answer BEST shows an animal's adaptation to the tropical rain forest? a. camouflage in a tree frog c. an elephant's long trunk b. the long neck of a giraffe d. migration of birds in winter 32. A mechanism of Darwin's proposed theory is. a. artificial selection c. variation b. evolution d. all of these 33. The founder of modern evolution theory is considered to be. a. Charles Darwin c. Stephen Jay Gould b. Alexander Oparin d. Lynn Margulis 34. Upon close examination of the skeleton of an adult python, a pelvic girdle and leg bones can be observed. These features are an example of. a. artificial selection c. vestigial structures b. homologous structures d. comparative embryology 35. Which combination of characteristics in a population would provide the greatest potential for evolutionary change? a. small population, few mutations c. large population, few mutations b. small population, many mutations d. large population, many mutations 36. The theory of continental drift hypothesizes that Africa and South America slowly drifted apart after once being a single landmass. The monkeys on the two continents, although similar, show numerous genetic differences. Which factor is probably the most important in maintaining these differences? a. comparative anatomy c. geographic isolation b. comparative embryology d. fossil records 37. Which of the following is not a factor that causes changes in the allelic frequencies of individuals in a population? a. stabilizing selection c. random selection b. directional selection d. disruptive selection 4

5 38. When checking shell color for a species of snail found only in a remote area seldom visited by humans, scientists discovered the distribution of individuals that is shown in the graph in Figure Based on the information shown in the graph, the snail population is undergoing. Figure 15-1 a. stabilizing selection c. artificial selection b. disruptive selection d. directional selection 39. What type of adaptation is shown in Figure 15-4? Figure 15-4 a. mimicry c. artificial selection b. camouflage d. homologous structure 40. The structures shown in Figure 15-5 are. Figure 15-5 a. homologous c. analogous b. heterologous d. vestigial 5

6 Figure Which type of natural selection showed in Figure 15-6 favors average individuals? a. A c. C b. B d. D 42. Which type of natural selection shown in Figure 15-6 would favor giraffes that need to reach the tallest branches to eat? a. A c. C b. B d. D 43. Why might the beak of the Akialoa, pictured in Figure 15-7, developed this way? Figure 15-7 a. to reach nectar in flowers c. to scoop up fish b. to dig through tree bark for insects d. to crack open seeds 6

7 44. The major anatomical difference between hominids and the apes is that the foramen magnum is in hominids. a. less developed c. thicker b. located at the bottom of the skull d. all of these 45. Which of the following groups are representative of the first primates? a. lemurs c. New World monkeys b. Old World monkeys d. apes 46. Tailless primates that are most like humans are the. a. apes c. New World monkeys b. Old World monkeys d. lemurs 47. New World monkeys are said to have an extra hand, the. a. opposable thumb c. nails on toes b. prehensile tail d. flexible fingers and toes 48. Lemurs and lorises are members of the primate group called. a. Haplorhines c. Strepsirrhines b. Anthropoids d. Huminoids 49. Primates are adapted to live in trees because their eyes. a. are in the front of their heads c. see in stereovision b. detect color d. all of these 50. The anthropologists who discovered the skull of Homo habilis were. a. the Leakeys c. the Johansons b. the Darts d. the Priestleys 51. Purgatorius is thought to be the earliest of primate fossils. It lived about. a years ago c. 8 million years ago b. 2 million years ago d. 66 million years ago 52. It has been determined that the earliest primates probably lived in the. a. grasslands c. forests b. mountains d. deserts 53. The hominid that had the most advanced toolmaking abilities and spoken language was. a. Cro-Magnon c. Purgatorius b. Neanderthal d. Homo habilis 54. As primates evolved, they developed. a. a good sense of smell and large lower vertebrae b. good vision and large teeth c. more complex brains and upright posture d. large teeth and a well-developed collar bone 55. The first hominids to make and use simple stone tools were. a. Homo sapiens c. Australopithecus afarensis b. Homo habilis d. Australopithecus africanus 56. The earliest primate identifiable from the fossil record is. a. Purgatorius c. Neanderthalus b. Australopithecus d. Afarensis 57. Most early hominid fossils have been found in. a. Egypt c. Africa b. France d. North America 7

8 58. The skeleton of the hominid nicknamed "Lucy" gave anthropologists evidence that. a. cavemen coexisted with dinosaurs b. Neanderthals coexisted with Homo habilis c. upright walking evolved after large brains d. upright walking evolved before large brains 59. Which is the oldest hominid species to be unearthed? a. Homo habilis c. Australopithecus afarensis b. Homo erectus d. Australopithecus africanus 60. Evidence for the determination of bipedal locomotion in an animal could be found by an examination of the. a. pelvis c. finger (carpal) b. upper arm (humerus) d. jaw 61. The skulls and pelvic bones of australopithecines have structures that appear those of apes and modern humans. a. vestigial to c. intermediate between b. nothing like d. identical to 62. Some primate skeletons were located in a cave in association with these things: a variety of tools, the charred bones of some animals they had cooked and eaten, and numerous paintings on the walls. Carbon-14 dating techniques determined that the bones and other artifacts were about years old. The skeletal remains probably belonged to. a. afarensis c. Cro-Magnons b. Homo habilis d. Homo erectus 63. Evidence that Homo erectus was more intelligent than its predecessors would include. a. a small cranial capacity as indicated by their skeletal remains b. involved messages they wrote on cave walls c. signs of agriculture and tilled fields d. tools such as hand axes that have been found near their fire pits 64. Which factor may have played a large role in human evolution? a. a geologic event that released much radiation into the environment, which in time resulted in an increased mutation rate b. climatic changes that caused existing primates to search for new food sources c. flooding due to melting glaciers causing primates to seek refuge in the trees d. massive grassland fires that caused existing primates to flee to the mountains 8

9 Figure Which adaptation shown in Figure 16-2 is not used for climbing? a. A c. C b. B d. D 66. Which adaptation shown in Figure 16-2 was lost as monkeys evolved into homonoids? a. A c. C b. B d. D Figure According to Figure 16-3, which species shares the closest ancestor with humans? a. A c. C b. B d. D 68. According to Figure 16-3, which was the first primate to evolve? a. A c. C b. B d. D 9

10 69. Where would orangatans fall in Figure 16-3? a. between gorillas and chimpanzees c. above chimpanzees b. between gorillas and lemurs d. between lemurs and gibbons 70. Predict where homo habilus would fall in Figure a. between gorillas and chimpanzees c. above chimpanzees b. between gorillas and lemurs d. between lemurs and gibbons Figure Which characteristic of the skulls in figure 16-4 shows an increase in intelligence? a. increased brain cavity size c. smaller eye sockets b. decreased teeth size d. rounder jaw 72. Which characteristic of the skulls in Figure 16-4 most impacts diet? a. increased brain cavity size c. smaller eye sockets b. decreased teeth size d. rounder jaw 73. Predict what will happen to the characteristics shown in Figure 16-4 as evolution continues. a. skulls will get smaller c. brain cavity size will increase b. teeth will get smaller d. heads will get flatter Completion Complete each statement. 74. Structures called, capable of growth and metabolism, have been produced in the laboratory. Structures like these may have eventually evolved into heterotrophic prokaryotes. 75. Organisms known as are chemosynthetic autotrophs that survive in harsh conditions where there is little sunlight or oxygen. 76. The ancient belief that nonliving materials could be transformed into living organisms was referred to as. 77. The idea that life arises only from life is referred to as. 78. The evolution of an ancestral species into an array of species that occupy diverse habitats is called. 79. Any structure that is reduced in function in a living organism but may have been used in an ancestor is known as a(n). 80. The concept that evolution occurs over long periods of stability that are interrupted by geologically brief periods of change is known as. 10

11 81. is a mechanism for change in a population in which organisms with favorable variations live, reproduce, and pass on their favorable traits. 82. Any species with a multiple set of chromosomes is known as a(n). 83. is the type of selection that favors average individuals in a population. 84. The alteration of allelic frequencies by chance processes is known as. 85. The is the percentage of a particular allele in a population. 86. The total number of genes present in a population is the. 87. A variety of structural adaptations called provides protection for an organism by copying the appearance of another species. 88. A structural adaptation enabling an organism to blend in with its environment is. 89. is a technique in which the breeder selects particular traits. 90. African skulls that show both humanlike and apelike characteristics are thought to be derived from early African primates and are collectively referred to as. 91. Homo sapiens may have first evolved by years ago, and evidence from burial sites around years ago indicates the use of communication by one group of people called the. 92. A group of people called the lived from to years ago, when they disappeared from the fossil record. 93. The ability to touch the thumb to the forefinger, permitting objects to be tightly grasped, is called. 94. Modern humans and humanlike fossils are classified as. 95. A distinctive characteristic of humans is locomotion, the ability to walk on two legs in an upright position. 96. Anthropologists propose that modern primates have evolved from two groups, the strepsirrhines and the. Short Answer 97. Explain how the evolution of photosynthetic organisms helped protect life from the sun's ultraviolet radiation. 98. Explain the relationship between early photosynthetic autotrophs and the eventual rise of aerobic life-forms. 99. How did Stanley Miller and Harold Urey's experiments affect modern ideas about the origin of life on Earth? 100. How did Francesco Redi and Louis Pasteur support the concept of biogenesis with their experiments? 101. How do scientists learn about organisms of the past when studying fossils? 102. Discuss four types of fossils and how they are formed. 11

12 Figure What major evolutionary event occurred at the point on the graph indicated by Z in Figure 14-3? 104. How did the evolution of photoautotrophs affect the level of oxygen in the atmosphere? 105. Describe what major event occurred in the evolution of life on Earth at point X, which is directly related to the change in the graph in Figure Figure Based on the fossil record shown in Figure 14-2, explain what has happened to the type of habitat found in the area as time passed Assuming that the oldest of the strata in Figure 14-2 is layer IV and that the youngest is layer I, name and describe two techniques that could be used to determine the age of fossil A How do changes in genetic equilibrium lead to speciation? 109. List and describe the indirect evidence available to support the theory of evolution What direct evidence is available to support the theory of evolution? 111. How is Darwin's theory of evolution by natural selection related to the origin of structural and physiological adaptations? 112. Summarize Darwin's theory of evolution by natural selection. 12

13 Figure A study of the squirrel population in a large northern city revealed that many of the squirrels inhabited large park areas that were also populated by numerous squirrel predators. The graph in Figure 15-2 reflects the data collected in regard to color and number of squirrels. Explain how this type of disruptive selection can lead to the separation of this population into two distinct species A study of the squirrel population in a large northern city revealed that many of the squirrels inhabited large park areas that were also populated by numerous squirrel predators. The graph in Figure 15-2 reflects the data collected in regard to color and number of squirrels. Explain why the light- and dark-colored squirrels might be selected for and the medium-colored squirrels selected against. A biologist studying a variety of fly in the rain forest noticed that the types of foods the fly preferred were located either high in the trees or in the foliage on the ground. There didn't seem to be any of the preferred foods anywhere in between. An experiment was designed that would select for a genetically determined behavior known as geotaxis. If a fly shows positive geotaxis, it flies downward. If a fly shows negative geotaxis, it flies upward. To conduct the experiment, the flies being studied were marked and placed in a maze (illustrated in Figure 15-3). Each fly was placed in the "start" chamber. To exit from this area, the fly had to make a decision about which of the three exits to enter. One exit faced upward, indicating negative geotaxis, and another exit aimed downward, indicating positive geotaxis. A third exit permitted the fly to remain on middle ground. Each fly was placed in the maze 15 times and its choice of direction recorded. Some flies consistently went upward and entered the food vial at the end of the exit tube. Others consistently went downward and entered the food vial at the lower end. Some flies chose the upward and downward exits equal numbers of times; others went for the middle exit. Figure What might eventually happen if, in the wild, the flies developed into two populations with one showing positive geotaxis and the other showing negative geotaxis? Refer to Figure What might be acting in the flies' environment to select for flies that do not exhibit a distinct preference for flying upward at every trial or downward at every trial? Refer to Figure

14 117. Referring to Figure 15-3, describe what would be happening to the frequency of the allele for negative geotaxis in the above question If the selection of direction is a genetic trait, what should happen when flies consistently selecting the upward exit are mated and those selecting the downward exit are mated, and the "no preference" and middle choice flies are discarded? Refer to Figure What type of selection pressure is operating in this experiment? Use Figure 15-3 to explain your answer In terms of evolution and natural selection, why would the researcher suspect that the flies being studied would show geotaxis? Refer to Figure Summarize the major anatomical changes in hominids during human evolution Describe the apes Compare and contrast Old World and New World monkeys Describe some of the adaptations primates have for dwelling in trees Explain why we are still piecing together a picture of how human evolution occurred, and how is it possible that our understanding of it might be flawed? 126. Why is bipedal locomotion probably the most important of all hominid traits? 127. Early primates spent most, if not all, of their time in the trees. How did their successful adaptations there eventually lead to important hominid adaptations? 128. When African forests declined and were replaced with vast areas of grassland, competition for food among animal species intensified. In an attempt to survive, hominids radiated outward from small forested areas. A vegetarian group, the australopithecines, emerged a few thousand years after the cooling period 2.8 million years ago. These hominids had to rely on seeds and tubers during the harsher seasons and on dense vegetation along riverbanks during the remainder of the year. Exploiting a variety of habitats at about the same time as the australopithecines was the first representative of the genus Homo. Members of this group consumed many kinds of food, including meat. How would a diet of meat select for a different jaw and tooth structure than is seen in earlier primates? 129. When African forests declined and were replaced with vast areas of grassland, competition for food among animal species intensified. In an attempt to survive, hominids radiated outward from small forested areas. A vegetarian group, the australopithecines, emerged a few thousand years after the cooling period 2.8 million years ago. These hominids had to rely on seeds and tubers during the harsher seasons and on dense vegetation along riverbanks during the remainder of the year. Exploiting a variety of habitats at about the same time as the australopithecines was the first representative of the genus Homo. Members of this group consumed many kinds of food, including meat. How would a diet of meat improve the chances of this group's survival, compared to australopithecines? 14

15 It is speculated that environmental changes in the African habitat from warm, moist forest to cool, dry grassland exerted selection pressures on all native species, including prehumans. Of all the theories attempting to explain hominid evolution, the one presently receiving much attention links the emergence of humankind to widescale climatic change. Two such major events in human evolution occurred, the first 2.8 million years ago, and the second occurred 1 million years ago. Ocean-bottom core samples (see Figure 16-1) taken from the west coast of Africa, the Arabian Sea, and the Gulf of Aden off the east coast of Africa lend credibility to this theory. A thick layer of dust and silicate particles has been found in the cores at levels determined to have been deposited 2.8 million and 1 million years before the present. Scientists attribute the deposits to the fact that grasses draw large quantities of silicates from the soil and concentrate them in their tissues for structural use. In a grassland environment, as grasses live, die, and decompose over many years, quantities of silicates accumulate in the surface soil. Deposits of dust and silicates also coincide with ice sheet formation and the onset of two ice ages in the Northern Hemisphere. Computer models show that the cooling and ice sheet formation influenced weather in both hemispheres. The models illustrate how cool, dry winds would have been diverted toward Africa as the ice sheets grew. Another important piece of information has been obtained from the Gulf of Aden core. It contains volcanic ash, along with dust and silicates blown by monsoon winds from the Rift Valley. This type of ash is also found in association with some hominid fossils discovered in the Rift Valley. Figure In what way does the presence of volcanic ash in the Gulf of Aden cores and in the Rift Valley help in tracing human evolution? Refer to Figure Describe what the African environment might have been like 2.0 million years ago. You may refer to Figure Describe the African environment that existed approximately 2.8 million and 1 million years ago. Use Figure 16-1 to explain your answer. 15

16 Problem Radioactive isotopes, atoms with unstable nuclei, decay over time, giving off radiation as they break down. The decay rate of every radioactive element is known; moreover, radioactive decay continues at a steady rate. Scientists compare the amount of the original radioactive element to the amount of the new element present, which has formed as a result of the decay. Suppose that you start with 100 g of a certain radioisotope that decays to half its original amount in years. Amount of Parent Material Amount of Daughter Material Years Passed 100 grams 0 grams grams grams Table On the grid in Figure 14-1, graph the data in Table 14-1 in order to show the relationship between the passage of time and the amount of original radioisotope. Then, place an X on the graph to indicate the point at which modern humans first appeared on Earth. Consider time 0 as that point at which the decay of the full amount of the isotope begins. The year point is the present time. Figure Complete Table 14-1 so that the amount of parent material (original radioisotope) and the amount of daughter material (nonradioactive end product) are correct for the number of years passed. 16

17 Evolution Answer Section MULTIPLE CHOICE 1. ANS: B PTS: 1 DIF: B OBJ: 14-4 NAT: C3 C6 D2 STA: ANS: B PTS: 1 DIF: B OBJ: 14-3 NAT: C1 C3 C6 STA: ANS: B PTS: 1 DIF: B OBJ: 14-3 NAT: C1 C3 C6 STA: ANS: A PTS: 1 DIF: B OBJ: 14-3 NAT: C1 C3 C6 STA: ANS: A PTS: 1 DIF: B OBJ: 14-2 NAT: C3 C6 G1 STA: ANS: D PTS: 1 DIF: B OBJ: 14-2 NAT: C3 C6 G1 STA: ANS: D PTS: 1 DIF: B OBJ: 14-1 NAT: C3 C6 G1 8. ANS: B PTS: 1 DIF: B OBJ: 14-1 NAT: C3 C6 G1 9. ANS: C PTS: 1 DIF: B OBJ: 14-1 NAT: C3 C6 G1 10. ANS: D PTS: 1 DIF: B OBJ: 14-5 NAT: C1 C3 C6 STA: ANS: B PTS: 1 DIF: B OBJ: 14-4 NAT: C3 C6 D2 STA: ANS: A PTS: 1 DIF: B OBJ: 14-1 NAT: C3 C6 G1 13. ANS: B PTS: 1 DIF: B OBJ: 14-1 NAT: C3 C6 G1 14. ANS: B PTS: 1 DIF: B OBJ: 14-4 NAT: C3 C6 D2 STA: ANS: C PTS: 1 DIF: B OBJ: 14-5 NAT: C1 C3 C6 STA: ANS: B PTS: 1 DIF: A OBJ: 14-2 NAT: C3 C6 G1 STA: ANS: D PTS: 1 DIF: A OBJ: 14-2 NAT: C3 C6 G1 STA: ANS: A PTS: 1 DIF: A OBJ: 14-2 NAT: C3 C6 G1 STA: ANS: A PTS: 1 DIF: B OBJ: 15-6 NAT: C6 F4 G1 STA: ANS: A PTS: 1 DIF: B OBJ: 15-6 NAT: C6 F4 G1 STA: ANS: D PTS: 1 DIF: B OBJ: 15-2 NAT: C3 C6 F4 STA:

18 22. ANS: A PTS: 1 DIF: B OBJ: 15-2 NAT: C3 C6 F4 STA: ANS: C PTS: 1 DIF: B OBJ: 15-3 NAT: C3 G1 G3 STA: ANS: D PTS: 1 DIF: B OBJ: 15-1 NAT: C3 C6 G3 STA: ANS: B PTS: 1 DIF: B OBJ: 15-6 NAT: C6 F4 G1 STA: ANS: B PTS: 1 DIF: B OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: C PTS: 1 DIF: B OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: A PTS: 1 DIF: B OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: C PTS: 1 DIF: B OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: C PTS: 1 DIF: B OBJ: 15-3 NAT: C3 G1 G3 STA: ANS: A PTS: 1 DIF: B OBJ: 15-2 NAT: C3 C6 F4 STA: ANS: D PTS: 1 DIF: B OBJ: 15-1 NAT: C3 C6 G3 STA: ANS: A PTS: 1 DIF: B OBJ: 15-1 NAT: C3 C6 G3 STA: ANS: C PTS: 1 DIF: B OBJ: 15-3 NAT: C3 G1 G3 STA: ANS: B PTS: 1 DIF: B OBJ: 15-5 NAT: C6 F4 G1 STA: ANS: C PTS: 1 DIF: B OBJ: 15-5 NAT: C6 F4 G1 STA: ANS: C PTS: 1 DIF: B OBJ: 15-5 NAT: C6 F4 G1 STA: ANS: D PTS: 1 DIF: B OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: B PTS: 1 DIF: B OBJ: 15-2 NAT: C3 C6 F4 STA: ANS: C PTS: 1 DIF: B OBJ: 15-3 NAT: C3 G1 G3 STA: ANS: A PTS: 1 DIF: A OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: C PTS: 1 DIF: A OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: A PTS: 1 DIF: A OBJ: 15-5 NAT: C6 F4 G1 STA: ANS: B PTS: 1 DIF: B OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: A PTS: 1 DIF: B OBJ: 16-3 NAT: C3 C4 G2 STA:

19 46. ANS: A PTS: 1 DIF: B OBJ: 16-2 NAT: C6 G2 G3 STA: ANS: B PTS: 1 DIF: B OBJ: 16-1 NAT: C6 G2 G3 STA: ANS: C PTS: 1 DIF: A OBJ: 16-2 NAT: C6 G2 G3 STA: ANS: D PTS: 1 DIF: B OBJ: 16-1 NAT: C6 G2 G3 STA: ANS: A PTS: 1 DIF: B OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: D PTS: 1 DIF: A OBJ: 16-3 NAT: C3 C4 G2 STA: ANS: C PTS: 1 DIF: B OBJ: 16-1 NAT: C6 G2 G3 STA: ANS: A PTS: 1 DIF: B OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: C PTS: 1 DIF: B OBJ: 16-3 NAT: C3 C4 G2 STA: ANS: B PTS: 1 DIF: B OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: A PTS: 1 DIF: B OBJ: 16-3 NAT: C3 C4 G2 STA: ANS: C PTS: 1 DIF: B OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: D PTS: 1 DIF: B OBJ: 16-4 NAT: C3 C6 G3 STA: ANS: C PTS: 1 DIF: B OBJ: 16-4 NAT: C3 C6 G3 STA: ANS: A PTS: 1 DIF: B OBJ: 16-4 NAT: C3 C6 G3 STA: ANS: C PTS: 1 DIF: B OBJ: 16-4 NAT: C3 C6 G3 STA: ANS: C PTS: 1 DIF: B OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: D PTS: 1 DIF: B OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: B PTS: 1 DIF: B OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: B PTS: 1 DIF: A OBJ: 16-1 NAT: C6 G2 G3 STA: ANS: D PTS: 1 DIF: A OBJ: 16-1 NAT: C6 G2 G3 STA: ANS: B PTS: 1 DIF: B OBJ: 16-3 NAT: C3 C4 G2 STA: ANS: D PTS: 1 DIF: A OBJ: 16-3 NAT: C3 C4 G2 STA: ANS: B PTS: 1 DIF: A OBJ: 16-3 NAT: C3 C4 G2 STA:

20 70. ANS: C PTS: 1 DIF: A OBJ: 16-3 NAT: C3 C4 G2 STA: ANS: A PTS: 1 DIF: A OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: B PTS: 1 DIF: A OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: C PTS: 1 DIF: A OBJ: 16-5 NAT: C3 G1 G3 STA: COMPLETION 74. ANS: protocells PTS: 1 DIF: B OBJ: 14-4 NAT: C3 C6 D2 STA: ANS: archaebacteria PTS: 1 DIF: B OBJ: 14-5 NAT: C1 C3 C6 STA: ANS: spontaneous generation PTS: 1 DIF: B OBJ: 14-4 NAT: C3 C6 D2 STA: ANS: biogenesis PTS: 1 DIF: B OBJ: 14-3 NAT: C1 C3 C6 STA: ANS: adaptive radiation PTS: 1 DIF: B OBJ: 15-6 NAT: C6 F4 G1 STA: ANS: vestigial structure PTS: 1 DIF: B OBJ: 15-3 NAT: C3 G1 G3 STA: ANS: punctuated equilibrium PTS: 1 DIF: B OBJ: 15-5 NAT: C6 F4 G1 STA: ANS: Natural selection PTS: 1 DIF: B OBJ: 15-1 NAT: C3 C6 G3 STA: ANS: polyploid PTS: 1 DIF: B OBJ: 15-5 NAT: C6 F4 G1 STA:

21 83. ANS: Stabilizing selection PTS: 1 DIF: B OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: genetic drift PTS: 1 DIF: B OBJ: 15-5 NAT: C6 F4 G1 STA: ANS: allelic frequency PTS: 1 DIF: B OBJ: 15-5 NAT: C6 F4 G1 STA: ANS: gene pool PTS: 1 DIF: B OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: mimicry PTS: 1 DIF: B OBJ: 15-2 NAT: C3 C6 F4 STA: ANS: camouflage PTS: 1 DIF: B OBJ: 15-2 NAT: C3 C6 F4 STA: ANS: Artificial selection PTS: 1 DIF: B OBJ: 15-5 NAT: C6 F4 G1 STA: ANS: australopithecines PTS: 1 DIF: B OBJ: 16-4 NAT: C3 C6 G3 STA: ANS: Neanderthals PTS: 1 DIF: B OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: Cro-Magnons PTS: 1 DIF: B OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: opposable thumb PTS: 1 DIF: B OBJ: 16-1 NAT: C6 G2 G3 STA: ANS: hominids PTS: 1 DIF: B OBJ: 16-5 NAT: C3 G1 G3 STA:

22 95. ANS: bipedal PTS: 1 DIF: B OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: haplorhines PTS: 1 DIF: B OBJ: 16-2 NAT: C6 G2 G3 STA: SHORT ANSWER 97. ANS: Photosynthetic organisms gave off O 2. Lightning converted some of the atmospheric oxygen into ozone (O 3 ). The ozone eventually built up a layer, which shields Earth's surface from the damaging effects of ultraviolet radiation. PTS: 1 DIF: A OBJ: 14-5 NAT: C1 C3 C6 STA: ANS: The photoautotrophs released oxygen, which was missing from the ancient atmosphere and necessary for aerobic respiration. Thus, the autotrophs produced the O 2 needed for the aerobic organisms to evolve. PTS: 1 DIF: A OBJ: 14-5 NAT: C1 C3 C6 STA: ANS: Miller and Urey's experiments supported the proposed and widely accepted hypothesis by Alexander Oparin that life began in the early oceans. Using a model of the primitive Earth atmosphere, oceans, and climatic conditions, Miller and Urey produced amino acids and other organic compounds. This demonstrated that the formation of life was possible establishing a foundation for the modern theories. PTS: 1 DIF: A OBJ: 14-4 NAT: C3 C6 D2 STA: ANS: Biogenesis is the idea that living things come only from other living things. Redi proved that large organisms, such as flies, do not spontaneously appear as had been previously thought. Pasteur took Redi's work even further and showed by experiments with broth that even bacteria do not spontaneously arise. PTS: 1 DIF: A OBJ: 14-3 NAT: C1 C3 C6 STA: ANS: Scientists identify different kinds of fossils found in sedimentary rock layers. From the way the rock is formed, the scientists can determine approximately when the organism lived and what the climate was like. By observing many different layers, conclusions can be drawn about the evolution of certain organisms from their fossils. PTS: 1 DIF: A OBJ: 14-1 NAT: C3 C6 G1 6

23 102. ANS: Answers will vary. Insects, plants, and small animals may be preserved in amber, a fossilized tree sap. Casts of organisms produce a replica of the original organism when minerals fill in a mold created by the organism. Trace fossils are the markings or evidence of animal activities, such as footprints and trails. The hard parts of organisms may be fossilized and replaced by minerals, creating a stone copy. PTS: 1 DIF: A OBJ: 14-1 NAT: C3 C6 G ANS: At this stage in Earth's history, aerobic organisms evolved. PTS: 1 DIF: A OBJ: 14-2 NAT: C3 C6 G1 STA: ANS: Photoautotrophs released O 2 into the atmosphere. Prior to that, there was no large source of atmospheric oxygen. PTS: 1 DIF: A OBJ: 14-2 NAT: C3 C6 G1 STA: ANS: Photoautotrophs evolved and released O 2 into the atmosphere. PTS: 1 DIF: A OBJ: 14-2 NAT: C3 C6 G1 STA: ANS: The leaf fossils in layer IV would indicate that this area was dry land with plants growing. The fish fossils in layers III and II indicate that the area was later under water and supported aquatic life. Layer I has no visible fossils. This could indicate that the area was a desert with little life and no water present to allow large numbers of fossils to form. Or, the conditions in the area did not allow the formation of fossils. PTS: 1 DIF: A OBJ: 14-1 NAT: C3 C6 G ANS: In order to determine the age of fossil A, scientists could use an absolute dating technique called radiometric dating. It relies on the rate at which unstable radioactive nuclei break down and, over time, give off radiation and eventually become different, stable elements. The ratio of the amount of unstable radioisotopes to the amount of the stable end product allows scientists to calculate how much time has passed since the fish was alive. Another method, relative dating, relies on scientists knowing the age of fossils above, below, or within the same layer as the unknown specimen. The age of fossil A can then be estimated. PTS: 1 DIF: A OBJ: 14-1 NAT: C3 C6 G ANS: Answers will vary. Allele frequency is altered by genetic drift, natural selection, migration, mutation, or nonrandom mating. This results in a change in genetic equilibrium in a population that is evolving. Evolution leads eventually to speciation. PTS: 1 DIF: A OBJ: 15-5 NAT: C6 F4 G1 STA:

24 109. ANS: Fossils can show evolutionary changes over time. Anatomical studies indicate evolutionary relationships. Vestigial structures indicate evolutionary pathways. Embryological development and genetic comparisons show evolution from a common ancestor. PTS: 1 DIF: A OBJ: 15-3 NAT: C3 G1 G3 STA: ANS: Direct evidence that supports the theory of evolution is drug resistance by bacteria, pesticide resistance by insects, and changes in allele frequencies within certain other populations such as the peppered moth. PTS: 1 DIF: A OBJ: 15-3 NAT: C3 G1 G3 STA: ANS: Structural and physiological adaptations occur at random within populations because of adaptations. Darwin's theory explains how these are fixed within populations. PTS: 1 DIF: A OBJ: 15-2 NAT: C3 C6 F4 STA: ANS: Darwin's theory of evolution by natural selection can be summarized by the following four statements. First, variations exist within populations. Second, some variations are more advantageous for survival and reproduction than others. Organisms produce more offspring than can survive. Finally, over time, offspring of survivors will make up a larger proportion of the population. PTS: 1 DIF: A OBJ: 15-1 NAT: C3 C6 G3 STA: ANS: After a long period of time, squirrels with the once-most-common phenotype, medium fur color, will produce fewer and fewer offspring and will gradually be eradicated. The light- and dark-colored individuals will live and reproduce successfully. After a while, disruptive selection will concentrate the color distribution at the two extremes. Eventually, the two groups may no longer recognize each other for mating purposes. This reproductive isolation could lead to the two types becoming separate species. Another possibility with the same end result is that these squirrels would tend to survive most successfully in areas where either dark or light coat color variation would be most advantageous. This would lead to geographic isolation. PTS: 1 DIF: A OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: The light-colored squirrels blend in well with the soil found in the area and with the leaves that fall from the trees and cover the ground in the autumn. The darker-colored squirrels blend in well with the paved walkways of the park area and also with the darkened tree trunks. The medium-colored squirrels would be more visible to predators and thus be selected against. PTS: 1 DIF: A OBJ: 15-4 NAT: C2 C4 G1 STA:

25 115. ANS: Eventually, the two populations would become reproductively isolated owing to their height preferences. Two distinct species with their separate gene pools would result. PTS: 1 DIF: A OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: The preferred foods could ripen at different times so that at one point in the year, it would be beneficial to fly upward and at a different time of the year, it would be more productive to fly downward. It might be, for example, that they feed on the pollen or other product of a particular species of flower. The flower may open only in the evening. So at that time of the day, the fly would do better to fly upward toward the flower. At other times, the fly may do better moving downward. There could also be a variety of predators that feed on the flies. Perhaps some of these predators also have preferred niches that are related to height levels in the vegetation. PTS: 1 DIF: A OBJ: 15-2 NAT: C3 C6 F4 STA: ANS: The frequency of the allele for negative geotaxis would be decreasing. PTS: 1 DIF: A OBJ: 15-5 NAT: C6 F4 G1 STA: ANS: You should end up with two different types of flies. One type will consistently fly only upward and the other will fly only downward. PTS: 1 DIF: A OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: Disruptive selection would be operating. The two extremes are being favored while the middle choice (sometimes positive geotaxis and sometimes negative) is being selected against. This is true because the middle flies are being discarded in the experiment while the two extremes are being retained and allowed to mate. PTS: 1 DIF: A OBJ: 15-4 NAT: C2 C4 G1 STA: ANS: It would be reasonable to expect that the flies would move either directly upward toward food or directly downward toward food because there wasn't anything for them to eat in between those areas. PTS: 1 DIF: A OBJ: 15-4 NAT: C2 C4 G1 STA:

26 121. ANS: Hominids are bipedal, with large brains. The braincase was originally apelike, and the first australopithecines had a face and teeth that were chimplike. The position of the foramen magnum was at the bottom of the braincase. A. afarensis and A. africanus had larger teeth and jaws that enabled them to eat tough plant materials. Neanderthal humans were powerfully built and were replaced by Cro-Magnons, who were apparently much like modern humans of today. PTS: 1 DIF: A OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: Apes are primates without tails. They are the closest animal relatives of humans. Apes live in Africa and Southeast Asia, are tailless, and have large brains. Apes include chimpanzees, gibbons, gorillas, orangutans, and siamangs. Although all groups have been observed occasionally to kill and eat animals, all are herbivores. PTS: 1 DIF: A OBJ: 16-2 NAT: C6 G2 G3 STA: ANS: Old World monkeys are natives of Africa and Asia. They are a varied group with most species living in trees. Although most species are tropical, they are the only primates, other than humans, that naturally occur outside the tropics. New World monkeys are native to Central and South America. All live in trees and have prehensile tails. These monkeys travel from tree to tree by using their hands for grasping as they swing through the branches. PTS: 1 DIF: A OBJ: 16-2 NAT: C6 G2 G3 STA: ANS: Primates have a highly developed sense of vision with forward-facing eyes, stereoscopic vision, and color vision. Flexible shoulder and hip joints are important for climbing, swinging, and clinging to branches. Opposable thumbs allow tight grasping and manipulation of small objects. PTS: 1 DIF: A OBJ: 16-1 NAT: C6 G2 G3 STA: ANS: The fossil record is not complete. Many of our interpretations of which primate or hominid preceded the other are based on fragments of skeletons. In addition, ancient human fossils are rare due to poor conditions for fossilization at most of the sites. PTS: 1 DIF: A OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: Being bipedal allowed hominids to use their hands for tasks other than locomotion, such as toolmaking and food gathering. PTS: 1 DIF: A OBJ: 16-5 NAT: C3 G1 G3 STA:

27 127. ANS: Successful primate adaptations for arboreal life include three-dimensional (stereoscopic) vision, an opposable thumb, the rotating ball-and-socket shoulder joint, and in some cases, the prehensile tail. All but the last adaptation have been significant in the evolution of hominids. Three-dimensional vision permits depth perception, which is critical for tree life, allows for better judgment of predator and prey distances, and also makes the fashioning of tools possible. The opposable thumb makes grasping and crafting tools possible. The flexible shoulder joint made movement through the trees easier for primates and, for hominids, was a necessary step in the evolution of efficient arm movements. PTS: 1 DIF: A OBJ: 16-1 NAT: C6 G2 G3 STA: ANS: The jaw of a vegetarian animal is necessarily heavy with broad, flat teeth. This allows for the chewing and grinding necessary to prepare the food for further digestion. The tooth and jaw structure of an omnivore or carnivore does not require the same massive structure. Meat does not require the same amount and kind of mechanical processing. A meat eater would also need teeth modified for tearing the flesh of the animals consumed. PTS: 1 DIF: A OBJ: 16-4 NAT: C3 C6 G3 STA: ANS: By eating meat, the chances of survival were greatly increased because meat is available year-round. Thus, eating a variety of foods, including meat, enhanced the quality of their diet. PTS: 1 DIF: A OBJ: 16-4 NAT: C3 C6 G3 STA: ANS: The presence of volcanic ash in the cores and in the Rift valley allows for a more precise time correlation between hominid fossils found on land and the climatic record provided by the ocean cores. PTS: 1 DIF: A OBJ: 16-5 NAT: C3 G1 G3 STA: ANS: The African habitat had changed from grassland back to large expanses of forest. This change would have been due to the recession of the ice sheets in the Northern Hemisphere, which resulted in a climate change from cool and dry to warm and moist. The warmer air could hold more moisture. Also, core samples did not contain silicates and dust deposits 2 million years ago, indicating that large expanses of grassland were no longer present. PTS: 1 DIF: A OBJ: 16-3 NAT: C3 C4 G2 STA: ANS: The silicate deposits indicate a relatively dry grassland environment. This hypothesis is reinforced by the computer models predicting cool, dry air being diverted toward Africa as ice sheets grew in the Northern Hemisphere. PTS: 1 DIF: A OBJ: 16-3 NAT: C3 C4 G2 STA:

28 PROBLEM 133. ANS: See Solution Solution 14-1 PTS: 1 DIF: A OBJ: 14-1 NAT: C3 C6 G ANS: Amount of Parent Material Amount of Daughter Material Years Passed 100 grams 0 grams 0 50 grams 50 grams grams 75 grams grams 87.5 grams grams grams grams grams Table 14-1 PTS: 1 DIF: A OBJ: 14-2 NAT: C3 C6 G1 STA: