Ecology The Economy of Nature Ninth Edition Test Bank
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Chapter 1 Multiple Choice 1. Which ecological level would be of most interest to an ecologist studying adaptations? a. ecosystem b. population c. individual d. community ANSWER: c 2. Which of the following is NOT a property used in the study of populations? a. density b. change in size c. composition d. interactions with other populations ANSWER: d 3. Which level of ecological hierarchy includes the movement of water and air? a. community b. population c. ecosystem d. biosphere ANSWER: d 4. A group of organisms that interbreeds in nature and produces fertile offspring is called a a. population. b. species. c. community. d. prokaryote. ANSWER: b 5. The boundaries of communities are a. difficult for species to cross. b. flexible. c. clear and distinct. d. never overlapping. ANSWER: b 6. Which is the correct hierarchy of ecological systems, from smallest to largest? a. ecosystem, biosphere, community, population, individual b. individual, community, population, ecosystem, biosphere c. individual, population, ecosystem, biosphere, community Copyright Macmillan Learning. Powered by Cognero.
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Chapter 1 d. individual, population, community, ecosystem, biosphere ANSWER: d 7. Which of the following systems is composed of assemblages of organisms together with their physical and chemical environments? a. organism b. population c. community d. ecosystem ANSWER: d 8. An ecologist who studies populations would most likely be interested in a. adaptations that help individual organisms live in their environment. b. births and deaths of individuals belonging to a particular species in a particular place. c. the number and relative abundance of species living in a particular place. d. physical and chemical transformations of energy and materials in the soil, atmosphere, and water. ANSWER: b 9. The first law of thermodynamics states that a. life requires energy to be continually added to Earth. b. matter cannot be created or destroyed. c. when energy changes form, some energy is lost. d. energy cannot be created or destroyed, but only change form. ANSWER: d 10. In a dynamic steady state a. there are no inputs or outputs to the system. b. the second law of thermodynamics does not apply. c. there is no net change in the system. d. the system will continue to grow. ANSWER: c 11. In evolution by natural selection, which of the following is true? a. All individuals within a population are identical. b. Some individuals have a higher fitness because of their traits. c. Offspring inherit every trait from both parents. d. The fitness of an individual refers to the strength of the individual. ANSWER: b 12. How can species interactions increase the rate at which species evolve? a. Interactions reduce the effects of natural selection. Copyright Macmillan Learning. Powered by Cognero.
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Chapter 1 b. Interactions increase the fitness of all individuals. c. Interactions make certain traits more useful. d. Interactions reduce the genetic variety in individuals. ANSWER: c 13. A phenotype is a. the traits an individual can pass on to its offspring. b. the expression of an individual’s traits. c. the genes an individual possesses. d. a trait caused by interaction with another species. ANSWER: b 14. To maintain a dynamic steady state in a community, which two factors must balance? a. new species arrivals and current species extinctions b. immigration and emigration c. births and deaths d. food consumed and energy expended ANSWER: a 15. At what ecological level does evolution occur? a. individual b. population c. ecosystem d. community ANSWER: b 16. Which feature is found in eukaryotic organisms but not in prokaryotic organisms? a. inability to photosynthesize. b. DNA. c. mitochondria. d. single-cell structure. ANSWER: c 17. Blue-green algae are a. protists. b. bacteria. c. plants. d. fungi. ANSWER: b 18. Organisms that use photosynthesis or chemosynthesis are Copyright Macmillan Learning. Powered by Cognero.
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Chapter 1 a. autotrophs. b. consumers. c. heterotrophs. d. herbivores. ANSWER: a 19. Which interaction is characterized by negative effects on the fitness of both species involved? a. predation b. herbivory c. commensalism d. competition ANSWER: d 20. A mixotroph is an organism that a. consumes dead organic matter. b. can be both a parasite and a predator. c. survives only because of a symbiotic relationship. d. can use multiple methods to obtain energy. ANSWER: d 21. The range of biotic and abiotic conditions a species can tolerate is its a. community. b. habitat. c. niche. d. ecosystem role. ANSWER: c 22. Which group of organisms function as decomposers? a. plants. b. animals. c. fungi. d. protists. ANSWER: c 23. Which consumes dead organic matter? a. detritivore b. herbivore c. parasite d. predator ANSWER: a Copyright Macmillan Learning. Powered by Cognero.
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Chapter 5
Which genotype(s) exhibit(s) phenotypic plasticity in response to predators? a. M only b. N only c. O only d. both M and N e. both N and O ANSWER: c 9. This figure shows the tail shape developed by three tadpole genotypes (M, N, and O) when raised in an environment with predators and an environment without predators. In the presence of predators, tadpoles with large tails have high fitness and tadpoles with small tails have low fitness. When predators are not present, tadpoles with large tails have low fitness and tadpoles with small tails have high fitness.
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Chapter 5
Which genotype(s) would have the highest average fitness across both environments? a. M only b. N only c. O only d. both M and N e. both N and O ANSWER: c 10. This figure shows the tail shape developed by three tadpole genotypes (M, N, and O) when raised in an environment with predators and an environment without predators. In the presence of predators, tadpoles with large tails have high fitness and tadpoles with small tails have low fitness. When predators are not present, tadpoles with large tails have low fitness and tadpoles with small tails have high fitness.
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Chapter 5
Under which of the following situations would the plastic genotype be favored over other genotypes? I. if all environments have predators II. if no environments have predators III. if environments with predators are as common as environments without predators a. situation I b. situation II c. situation III d. situations I and II e. situations I and III ANSWER: c 11. Which of the following statements about environmental cues is/are TRUE? I. Environmental cues are necessary for an organism to evolve adaptive phenotypic plasticity. II. Environmental cues can include smell, sight, and sound. Copyright Macmillan Learning. Powered by Cognero.
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Chapter 5 III. Environmental cues are used by animals but not by plants. a. I only b. II only c. III only d. I and II e. I, II, and III ANSWER: d 12. Which shows the order of phenotypically plastic traits from those that typically respond most rapidly to those that typically respond least rapidly? a. behavior, morphology, physiology b. physiology, morphology, behavior c. behavior, physiology, morphology d. morphology, behavior, physiology e. morphology, physiology, behavior ANSWER: c 13. Environmentally induced changes in an individual’s physiology are called a. acclimation. b. environmental cues. c. phenotypic trade-offs. d. nonplastic genotypes. ANSWER: a 14. When the protist Euplotes detects predators, it grows “wings” and other projections to discourage predators. However, developing the projections and wings slows down growth. This is an example of I. phenotypic trade-offs. II. phenotypic plasticity. III. inbreeding depression. a. I only b. II only c. III only d. I and II only e. I, II, and III ANSWER: d 15. Which statement about predator and prey phenotypic plasticity is accurate? I. Prey can change morphology to avoid predators. II. Predators can change morphology to capture prey. III. Both predators and prey exhibit phenotypic trade-offs. a. I only Copyright Macmillan Learning. Powered by Cognero.
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Chapter 10 bottom temperatures, and how species diversity was affected by temperature. According to the figure, what did they find? What did they conclude about the cause of the change in fish diversity?
ANSWER: Over this period of increasing bottom-water temperatures, the diversity of fish increased. This is likely because species from more southern waters moved into the North Sea, where they could survive newly warmed bottom-water temperatures. Copyright Macmillan Learning. Powered by Cognero.
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Chapter 10 51. Why are endemic species more at risk for becoming rare or endangered than cosmopolitan species? ANSWER: Endemic species live in a single, often isolated location. If habitat is lost through natural or anthropogenic disturbance, there may be no other habitat available to these species. Cosmopolitan species have very large geographic ranges that can span several continents, so they can tolerate a much greater habitat loss or other disturbance. 52. Compare and contrast the terms dispersion and dispersal. ANSWER: Both terms are related to spatial patterns of organisms. Dispersion refers to the spatial patterning of individuals of a particular species, and it can be described as clustered, evenly spaced, or random. Dispersal refers to movements of individuals within a population. The dispersal of individuals can affect their dispersion. For example, if individuals remain close to the place where they were born, a clumped dispersion may result. More active dispersal away from the natal site may result in evenly spaced or random dispersion patterns. 53. You conduct a mark-recapture survey of eastern fence lizards (Sceloporus undulatus) in a 2-hectare plot in eastern Arizona. You mark 250 lizards and are able to recapture 75, of which 24 are marked. What is the estimated size of the population of fence lizards in this plot? Calculate the estimated population size for the plot and the estimated lizard density per hectare and per square meter. Use the following formula: where M is the number of initially marked individuals, N is the population size, R is the number of recaptured marked individuals, and C is the total number of individuals recaptured. ANSWER:
54. Imagine that you are conducting a mark-recapture survey of common pill bugs (Armadillidium vulgare), a terrestrial isopod, in a field. Unbeknownst to you, the majority of the pill bugs molt between marking and recapturing. How does this affect your estimate of the population size? How could you have foreseen this? How could you prevent this in the future? ANSWER: Based on the equation for estimating population size using mark-recapture surveys, if the number of recaptured and marked (R) individuals was very small compared to the original number, the population estimate would be much higher than the actual population size. To avoid this problem, you could do a side experiment in which pill bugs captured at the same time as the original capture were placed in a contained terrarium to see what happened to marked pill bugs over the course of the study. You could also research the interval between molting and try to time the survey between molts. Copyright Macmillan Learning. Powered by Cognero.
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Chapter 10 55. Based on the relationship between geographic range and population, what would you expect to happen if a large portion of a species’ habitat is converted to agriculture? ANSWER: Habitat converted to agriculture would probably not be suitable for the species, and total geographic range for this species would decline. The decline in geographic range would most likely cause the population of the species to decline. 56. The relationship between population density and adult body size is demonstrated in many organisms. Would you expect this relationship to hold true for body size averaged across all developmental stages (juveniles to adults)? Why or why not? ANSWER: For some species, such as mice, the difference between sizes of adults and juveniles is not great, and the relationship would hold true. In other organisms the size difference can be immense. For example, adult giant sequoia trees are much larger than seedlings. Many seedlings of giant sequoia may die over time, until a small number reach adulthood. In the case of giant sequoias, the relationship would not hold true. 57. Researchers used an experimental design in which they cleared large patches of pine forest in five areas. The central cleared area served as the source of dispersers. The four remaining cleared patches were (1) a rectangular unconnected patch, (2) a rectangular patch connected to the central patch by a cleared path that served as a corridor, and (3) two rectangular patches with wings (patches with corridors that did not connect to other patches). The researchers were interested in the importance of habitat corridors to the movement of seeds, pollen, and butterflies between central and peripheral habitat patches. What was the purpose of the unconnected winged patches?
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Chapter 10
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Chapter 22 63. How has agriculture led to losses of genetic diversity? Why is this a problem? ANSWER: Modern livestock operations favor relatively few breeds of animals. Crop diversity has declined: Most people’s diets consist of just 12 species of plants. Commercial agriculture favors topproducing varieties rather than diversity. Loss of diversity can be a problem when a new pathogen or environmental challenge occurs for which the crops or livestock do not have resistance or adaptations. 64. Methylmercury is an organic mercury compound that is a waste product of industrial processes and also results from the burning of fossil fuels. Methylmercury has been shown to increase up food chains by biomagnification. Bigeye tuna (Thunnus obesus) can have tissue concentrations of methylmercury of 0.69 ppm (parts per million). Assuming a food web that starts with phytoplankton (0.00069 ppm) and a 10-fold biomagnification from each level in the food chain to the next level, calculate the concentration of methylmercury at each level in the food chain. How many levels are there in the food chain, including the phytoplankton and the tuna? ANSWER: Phytoplankton are assumed to be the first level in the food chain. Level 2, 0.00069 ppm × 10 = 0.0069 ppm Level 3, 0.0069 ppm × 10 = 0.069 ppm Level 4, 0.069 ppm × 10 = 0.69 ppm (tuna) There are four levels in this food chain. 65. You measure 1,000 mg of the pesticide DDT in the soil, and 30 days later the amount in the soil is 998.1 mg. What is the half-life (in years) of DDT in this soil? ANSWER:
66. The California condor (Gymnogyps californianus) reintroduction was very successful in increasing natural populations of condors. In addition to reintroduction, what strategies were used to conserve this species? ANSWER: Prior to reintroduction of condors, all known wild condors were captured and bred in captivity to increase their numbers. Biologists were able to increase the egg output of females and raise chicks in large numbers for release. Large areas of habitat were also preserved in southern California. Awareness of the importance of protecting the species was raised among the residents near condor habitat. 67. The reintroduction of wolves to Yellowstone National Park has had effects beyond the conservation of wolves. What are other benefits of the reintroduction? ANSWER: Reintroduction of wolves had cascading effects on the prey species that the wolves consume. Elk have changed their behavior to reduce predation, which has increased populations of aspens and cottonwoods that elk grazed. The populations of coyotes, a mesopredator, have declined because of competition with and predation by wolves. Scavenger populations have benefited from increased predation by wolves. The reintroduction of wolves has brought the ecosystem to more closely resemble its earlier condition when its fauna was intact. Copyright Macmillan Learning. Powered by Cognero.
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Chapter 22 68. Briefly describe what is known about the causes of the five past mass extinctions and the possible sixth mass extinction that may be under way. ANSWER: The cause of the first mass extinction (443 mya) is thought to have been an ice age that caused sea levels to drop and ocean chemistry to change. The cause of the second mass extinction (359 mya) is unclear, though it is known that much of the ocean lacked oxygen. The cause of the third mass extinction (248 mya) is likewise uncertain. The cause of the fourth mass extinction (200 mya) is believed to have been increased volcanic activity, an asteroid collision with Earth, and climate change. The cause of the fifth mass extinction (65 mya) is also thought to have been volcanic eruptions, an asteroid strike, and climate change, specifically an extended period of cooling. It is hypothesized that the possible sixth mass extinction under way (over the course of the past 10,000 years) is driven by increasing human population. 69. Explain how an insecticide like DDT, which was found in low concentrations in water after its application for insect control, nearly caused the loss of species like the bald eagle in some places in the United States during the 1960s. ANSWER: DDT is a fat-soluble chemical that is biomagnifiable as one proceeds up the food chain. Starting with low concentrations in the water after insecticide application, the DDT was taken up by phytoplankton (algae) in levels 10 times greater than that found in the water. The phytoplankton were then consumed by zooplankton and further magnification was observed as the DDT accumulated in the fat molecules of the zooplankton. This magnification continued through the various predator fish, ending at the top-level carnivore, the bald eagle. At each step (small fish, larger fish, and bald eagle) the DDT level increased as the chemical was stored in the fatty tissue of each species in the succeeding trophic levels. At the highest level (bald eagle), the level of DDT was problematic and caused a physiological impairment in eggshell formation. The eggshells were too thin and when adult eagles attempted to incubate their eggs, the thin-shelled eggs broke, killing the embryo inside. This biomagnifiable chemical nearly led to the loss of bald eagles during the 1960s. 70. It has been documented (see Figure 23.12) that forest cover has declined in many regions of the world for nearly the past 20 years. In other parts of the world, forest cover has increased during this time. Why do conservation biologists see both of these developments as potentially problematic for biodiversity? ANSWER: The loss of forest cover in many regions of the tropics (the Amazon, Southeast Asia, etc.) has led to a large number of species becoming critically endangered. In addition, in some regions (the United States, Europe, etc.) that have seen an increase in forest cover during the last 20 years, the original level of biodiversity/species composition has been lost because the trees being replanted are often a single or a few species with high economic value as opposed to a more naturally diverse forest structure.
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