Ecology Exam 2

84. At which stage of succession is facilitation usually the most significant factor? a. Early b. Middle c. Late d. Facilitation is equally important in middle and late stages.

a. Early

94. Plants with bacterial symbionts that fix _______ are often important players in _______ stages of succession. a. nitrogen; early b. phosphorus; late c. sulfur; early d. phosphorus; early

a. nitrogen; early

21. A fish maturing late with large body size and producing many small offspring would be said to have a(n) a. periodic life history. b. opportunistic life history. c. equilibrium life history. d. precocial life history. e. stress-tolerant life history.

a. periodic life history.

93. In their studies of succession in Glacier Bay, Alaska, Chapin and colleagues found that the survival rate of germinated spruce seeds was highest at the _______ stage. a. pioneer b. Dryas c. alder d. spruce

a. pioneer

64. What is the Shannon index value for an area in which only a single species is present? a. 0 b. 1 c. ‒1 d. Infinity

a. 0

51. In the study by Jennifer Hughes and colleagues, in which community did it appear that the species richness had been adequately sampled? a. A plant community from a forest in Michigan b. East Amazonian soil bacteria c. Human oral bacteria d. Costa Rican moths

a. A plant community from a forest in Michigan

45. Mushroom-feeding Drosophila species, including the species Drosophila neotestacea, D. falleni, D. putrida, and D. recens, are prevalent in the Great Lakes region of the United States. Suppose a biologist collects flies from three different communities and obtains the results shown in the tables. Reference: Ref 16-2 Based on the Shannon index, rank the species diversity from highest to lowest. a. Community 1 > Community 2 > Community 3 b. Community 1 > Community 3 > Community 2 c. Community 2 > Community 1 > Community 3 d. Community 3 > Community 2 > Community 1

a. Community 1 > Community 2 > Community 3

68. Which conclusion was the primary finding of Buss and Jackson's study of coral-associated invertebrates and algae in Jamaica? a. Competitive networks can be circular. b. Environmental context can change the outcome of species interactions. c. Diversity is maintained due to the existence of keystone species. d. Species diversity estimates vary with sampling effort.

a. Competitive networks can be circular.

71. Which statement about food webs is true? a. Most food webs do not include information about symbiotic relationships. b. All species occupy only a single trophic level in a food web. c. Food webs generally provide much information about the strengths of interactions across trophic levels. d. Food webs provide information about trophic and non-trophic interactions.

a. Most food webs do not include information about symbiotic relationships.

67. Refer to the diagram. Reference: Ref 16-5 Where would a keystone species most likely be located in the diagram? a. Position A b. Position B c. Position D d. Position E

a. Position A

79. Which value can be measured the most easily? a. Species richness b. Species evenness c. Species diversity d. Species evenness and species richness are equally easy to measure.

a. Species richness

18. Seeds bearing eliasomes are likely to be dispersed by a. ants. b. wind. c. water. d. birds. e. scatterhoarding mammals.

a. ants.

46. Ecologists are concerned about the establishment of invasive species in new areas because invasive species a. can have large ecological effects in their new communities. b. that become established are easy to control. c. are often toxic. d. always cause a decline in biological diversity of the communities they invade.

a. can have large ecological effects in their new communities.

32. In the Lotka-Volterra predation model, a prey (host) population in the absence of predators would a. grow exponentially. b. grow logistically. c. grow exponentially, and then crash when it has outstripped its own food supply. d. decline to extinction. e. The model makes no assumptions about what happens in the absence of predators.

a. grow exponentially.

22. The principle of allocation states a. if an organism uses energy for one function it reduces the amount of energy available for other functions. b. organisms have a tendency to select the smallest prey available rather than exert more energy in capturing larger prey. c. organisms that build larger nests produce fewer offspring. d. organisms have a tendency to allocate more time and energy to a single preferred offspring while neglecting others. e. plants allocate their energy such that larger seedlings come from smaller seeds.

a. if an organism uses energy for one function it reduces the amount of energy available for other functions.

90. In his studies of succession in Glacier Bay, Chapin found that as communities went from early to latter stages of succession, soil moisture _______ and nitrogen _______. a. increased; increased b. increased; decreased c. stayed about the same; increased d. decreased; increased

a. increased; increased

57. Suppose two populations of Anolis lizards are of equal size at the beginning of an experiment. One population (the experimental group) is exposed to a predator (16 predatory lizards), and the other (the control) is not. The final size of the experimental population is 50, and the final size of the control population is 200. What is the per capita interaction strength of predatory lizards on Anolis lizards? a. ln (4/16) b. ln (4/50) c. ln (16/4) d. ln (16/50)

a. ln (4/16)

44. The presence of a mutualist spider in a certain area improves the survival of an herbaceous shrub by reducing the impact of herbivorous insects. These spiders are preyed on by lizards, and lizards are eaten by birds. Reference: Ref 16-4 An increase in the density of lizards would most likely have a direct _______ effect on spiders and a _______ effect on the plant. a. negative; indirect negative b. negative; indirect positive c. negative; direct negative d. positive; indirect positive

a. negative; indirect negative

96. Suppose that a late succession plant that is surrounded by early succession plants grows at a rate of 0.5 cm per day. If the early succession plants are removed experimentally, the late succession plants are observed to grow at a rate of 0.9 cm per day. This experiment shows that the early succession plants have a _______ effect on the late succession plants, and this observation is most consistent with the _______ model of succession. a. positive; facilitation b. positive; inhibition c. negative; facilitation d. negative; inhibition

a. positive; facilitation

89. If Cowles is correct about succession, then a. space can be substituted for time. b. the unique conditions in particular locations are of great importance. c. we do not have the ability to make inferences about the changes in communities over time scales that span centuries. d. succession is usually unpredictable.

a. space can be substituted for time.

9. The Africanized honeybee stopped spreading southward through South America by about 1983 in response to a. unfavorable climatic factors. b. aggressive pest control measures. c. introduction of a species-specific parasite as a means of biological control. d. severe competition with the closely related European honeybee. e. None of the choices are correct.

a. unfavorable climatic factors.

83. Assume that the melting of a glacier is taking place at a constant rate of 50 meters per year, and that site A is 1.6 km farther from the ice edge than site B is. Based on this data, and the principle of "space for time substitution," we can assume that the conditions seen at site A in the year 2011 are the same as those that _______ seen at site B in _______. a. were; 1979 b. were; 1995 c. will be; 2027 d. will be; 2043

a. were; 1979

48. Four species of fish in a pond are found in equal abundance. The Shannon index of the fish community is therefore a. -1 [4 (ln 4)]. b. -4 [0.25 (ln 0.25)]. c. -0.25 [0.25 (ln 4)]. d. -0.25 (ln 0.25).

b. -4 [0.25 (ln 0.25)].

49. How many total trophic levels are present in a food web in which the top trophic level consists of secondary consumers? (Do not consider decomposers or omnivores.) a. 2 b. 3 c. 4 d. 5

b. 3

91. In the dunes near Lake Michigan studied by Cowles, the dominant plant species in the early stages of succession was a. spike grass. b. American beach grass. c. Indiana dune grass. d. Michigan cord grass.

b. American beach grass.

88. Farrell's studies of algal succession on the Oregon coast showed that a. algal succession is driven primarily by inhibition. b. Balanus facilitated the growth of algae by protecting them from limpet herbivory. c. Balanus facilitated the growth of algae by secretion of nitrogenous compounds. d. Limpets facilitated the growth of algae by providing surfaces on which they could rest.

b. Balanus facilitated the growth of algae by protecting them from limpet herbivory.

73. Which statement about the difference between a competitive network and a competitive hierarchy is true? a. A competitive network comprises more species than interaction networks. b. In a competitive hierarchy, one species dominates the interaction; in an interaction network, no one species dominates the interaction. c. The interactions are stronger in a competitive network than in interaction networks. d. In a competitive hierarchy, indirect species interactions always buffer strong competition; in interaction networks, they do not.

b. In a competitive hierarchy, one species dominates the interaction; in an interaction network, no one species dominates the interaction.

76. Which statement best describes the difference between the theoretical concept of a community and the ways in which communities are delineated in practice? a. In theory, a community is defined only by abiotic factors of the area; in practice, communities are delineated by biological attributes as well. b. In theory, communities consist of all species present; in practice, biologists usually study only a subset of the species. c. In theory, communities can be defined by physical or biological characteristics, but in practice, these characteristics are difficult to measure and are not used. d. There is no difference between the theoretical concept of a community and how it is defined in practice.

b. In theory, communities consist of all species present; in practice, biologists usually study only a subset of the species.

38. ______________ is/are defined as a group of potentially breeding organisms within a species in a given space and time. a. Density b. Populations c. Distribution d. Abundance e. Community

b. Populations

74. Which statement about the studies by Mary Power and colleagues on California rivers is true? a. In drought years the number of trophic levels increased. b. Species, such as the steelhead, that are keystone predators during normal years are minor players in the food web during drought years. c. The alga Cladophora completely died out during droughts. d. Species interactions remained constant despite changes in environmental conditions.

b. Species, such as the steelhead, that are keystone predators during normal years are minor players in the food web during drought years.

97. Suppose that following a lava flow, pine grass (a hypothetical species) is the first species to colonize the area. Chemicals produced by pine grass change the soil chemistry in the environment, but these chemicals have little or no effect on subsequent colonization by later species. Which model would best explain this scenario of succession? a. Inhibition b. Tolerance c. Facilitation d. Both a and b

b. Tolerance

80. Refer to the diagram. Reference: Ref 16-1 Which web in the diagram is an interaction web? a. Web I b. Web II c. Web III d. All of the above

b. Web II

1. Cornell studied the distribution of barnacles Chthamalus stellatus and Balanus balaoides along the coast of Scotland and indicated that, along with the physiology of each barnacle, ______________ also played a large role in their distribution pattern. a. topography b. competition c. salinity d. predation e. temperature

b. competition

87. Connell and Sousa criticized Sutherland's experiments on alternative stable states in fouling communities on the grounds that a. the experiments were conducted over too much time. b. fouling communities without predators may not be sustainable in nature. c. the system clearly demonstrated hysteresis. d. the predator-exclusion cages were not totally effective.

b. fouling communities without predators may not be sustainable in nature.

10. An annual plant when initially colonizing an area will probably demonstrate a. annual growth rate. b. geometric population growth. c. exponential growth rate. d. logistic growth. e. None of the choices are correct.

b. geometric population growth.

60. Cougars prey on both white-tailed deer and mule deer. Because of their shared predator, each deer species' abundance is affected by the presence of the other deer species. Reference: Ref 16-3 The cougar and the mule deer are engaged in a(n) a. direct interaction. b. indirect interaction. c. trophic facilitation. d. trophic cascade.

b. indirect interaction.

62. Cougars prey on both white-tailed deer and mule deer. Because of their shared predator, each deer species' abundance is affected by the presence of the other deer species. Reference: Ref 16-3 The white-tailed and mule deer are engaged in a(n) a. direct interaction. b. indirect interaction. c. trophic facilitation. d. predator-prey relationship.

b. indirect interaction.

25. Ecologists sometimes use __________________ as simpler representations of the complex natural world. a. character displacement b. mathematical or laboratory models c. competition coefficients d. replication e. None of the choices are correct.

b. mathematical or laboratory models

31. A species feeding on the tissue of its host, while not killing it directly, is a a. predator. b. parasite. c. parasitoid. d. cannibal. e. debilitator.

b. parasite.

15. If the age distribution diagram has the smallest concentration of individuals in the bottom portion or is considered to be an urn shape, this indicates that a. the population is stable b. the population is declining c. the population is growing slowly d. the population is growing rapidly e. cannot be determined

b. the population is declining

13. Human populations are clumped on a large scale with the greatest concentration in a. Africa. b. Europe. c. Asia. d. North America. e. South America.

c. Asia.

86. Bertness and Shumway's studies of high salt stress conditions in the middle intertidal regions of New England salt marshes led to which conclusion? a. Juncus drove Distchlis to extinction. b. Spartina inhibited colonization by Juncus. c. Distichlis facilitated colonization by Juncus. d. Distichlis inhibited colonization by Juncus.

c. Distichlis facilitated colonization by Juncus.

33. __________ consume live plant material but do not usually kill plants. a. Predators b. Pathogens c. Herbivores d. Parasites e. Parasitoids

c. Herbivores

6. Humans would best be represented by which of the following survivorships curves? a. III b. II c. I d. IV e. None of the choices are correct.

c. I

77. Which statement describes a limitation of a species accumulation curve in terms of its ability to determine whether species diversity has been adequately sampled? a. It can be used only for a community of large spatial scale. b. It can be used only for a community of small spatial scale. c. It assumes that the sampling methods are consistent throughout the study. d. It assumes a high Shannon index.

c. It assumes that the sampling methods are consistent throughout the study.

75. Which statement about the "killer alga," Caulerpa taxifolia, is false? a. It was unintentionally released into the Mediterranean by the Oceanographic Museum of Monaco. b. Its invasive range extends at least as far as Spain on the west and Croatia on the east. c. It is toxic to humans and other mammals. d. It has evolved cold resistance.

c. It is toxic to humans and other mammals.

47. Estimates show that oceans absorb about _______ of all the atmospheric CO2. a. 1% b. 10% c. 40% d. 48%

d. 48%

43. An experiment by Alsterberg and colleagues showed that with ocean acidification and warming, the biomass of benthic microalgae a. did not change with omnivores. b. declined without omnivores. c. increased with omnivores. d. Both a and b

d. Both a and b

85. Suppose you are studying succession patterns in two species, species A and species B, both small aquatic organisms that colonize bare surfaces underwater. You replicated Sutherland's experiments in this new system by placing bare tiles underwater in predator-protected areas and areas with predators. You collect data on the percent of cover for each species, as shown in the figure. Reference: Ref 17-2 Based on the data, what would you expect that a newly colonized area in a natural pond would look like? a. Species A would dominate species B, although species B would still occupy some space. b. Species A and B would coexist at about equal proportions. c. Species B would dominate species A, although species A would still occupy some space. d. The predators in the natural ponds would cause both species A and species B populations to decrease significantly.

c. Species B would dominate species A, although species A would still occupy some space.

70. Refer to the diagram. Reference: Ref 16-1 Which species in the diagram is an omnivore? a. Species A b. Species B c. Species C d. Species D

c. Species C

98. The figure is derived from studies of algal succession in the presence and absence of the barnacle Balanus and limpets. Which condition is represented by the red line (indicated by the black arrow)? a. The presence of both limpets and Balanus b. The presence of limpets and the absence of Balanus c. The presence of Balanus and the absence of limpets d. The absence of both limpets and Balanus

c. The presence of Balanus and the absence of limpets

72. Which statement about keystone predators is true? a. They usually are abundant in number and/or have disproportionately high biomass. b. They usually influence primary producers directly. c. They usually influence primary producers indirectly. d. They are the same as foundation species.

c. They usually influence primary producers indirectly.

30. The process of evolution toward niche divergence in the face of competition is called ____________. a. niche displacement b. niche evolution c. character displacement d. character evolution e. allopatric displacement

c. character displacement

36. In the Lotka-Volterra predation model, a predator population in the absence of prey (hosts) would a. grow exponentially. b. grow logistically. c. decline as predators die. d. decline at first, but then increase as predators switch to other modes of feeding. e. decline at first, but then reach a small equilibrium population size.

c. decline as predators die.

55. Menge and colleagues performed experiments in which they exposed some populations of mussels to sea stars and excluded sea stars from other mussel populations. Suppose two populations of mussels are the same size prior to treatment, and after treatment there are 600 mussels in the treatment without sea stars and 200 mussels in the treatment with sea stars. Suppose further that the sea star population consists of 10 individuals. What is the per capita interaction strength of sea stars on mussels? a. ln (3/10) b. (ln 600)/(ln 200) c. ln (0.33/10) d. ln (0.33/200)

c. ln (0.33/10)

20. Which of the following is NOT a characteristic favored by K-selection? a. low intrinsic rate of increase b. late reproduction c. many, small offspring d. repeated bouts of reproduction e. strong competitive ability

c. many, small offspring

56. Species that feed on more than one trophic level are called a. tertiary consumers. b. herbivores. c. omnivores. d. primary producers.

c. omnivores.

27. Joseph Connell discovered that Balanus barnacles were excluded from the upper intertidal zone by ____________, while Chthalamus barnacles were excluded from the middle intertidal zone by ___________. a. competition from mussels, prolonged immersion in water b. competition from mussels, competition with Balanus c. prolonged exposure to air, competition with Balanus d. prolonged exposure to air, competition with algae e. predation by wading birds, predation by starfish

c. prolonged exposure to air, competition with Balanus

53. Lions prey on animals such as zebras and wildebeest, which feed primarily on grasses. Lions thus should be considered a. primary consumers. b. herbivores. c. secondary consumers. d. tertiary consumers

c. secondary consumers.

59. The Shannon index is a measure of a. interaction strength. b. species richness alone. c. species diversity. d. the extent of trophic facilitation.

c. species diversity.

39. Density is defined as a. the number of individuals within a population. b. abundance. c. the number of individuals per unit area. d. the distribution of individuals within a given area. e. None of the choices are correct.

c. the number of individuals per unit area.

82. Alternative stable states most often arise a. in terrestrial ecosystems. b. in intertidal zones. c. when there are strong interactions among species. d. under the tolerance model of succession.

c. when there are strong interactions among species.

42. Although beavers are relatively rare, they have considerable influence over species interactions in communities in which they are present because of the dams that they construct. The beaver is thus an example of a(n) a. foundation species. b. ecosystem engineer. c. keystone species. d. Both b and c

d. Both b and c

100. The studies by Chapin and colleagues on Glacier Bay succession provide empirical support for which model of succession? a. Facilitation only b. Tolerance only c. Inhibition only d. Facilitation, tolerance, and inhibition

d. Facilitation, tolerance, and inhibition

65. What is the primary difference between interaction webs and food webs? a. Interaction webs include more trophic levels. b. Interaction webs include fewer trophic levels. c. Interaction webs do not consider primary producers, whereas food webs do. d. Interaction webs include non-trophic interactions; food webs do not.

d. Interaction webs include non-trophic interactions; food webs do not.

52. In their studies of a salt marsh community, Sally Hacker and colleagues found that removing _______ led to a(n) _______. a. Juncus; increase in the abundance of Iva b. Iva; increase in the abundance of Juncus c. Juncus; increase in the abundance of aphids through indirect effects d. Juncus; decrease in the abundance of aphids through indirect effects

d. Juncus; decrease in the abundance of aphids through indirect effects

54. Members of the same functional group must belong to the same a. guild. b. trophic level. c. taxonomic group. d. None of the above

d. None of the above

81. According to the _______ model of succession, the early successional species modify the environment so as to facilitate the subsequent colonization of other early colonizing species. a. facilitation b. tolerance c. inhibition d. None of the above

d. None of the above

66. Refer to the diagram. Reference: Ref 16-5 Where would a foundation species most likely be located in the diagram? a. Position A b. Position B c. Position C d. Position D

d. Position D

69. Refer to the diagram. Reference: Ref 16-1 Which species in the diagram is a primary producer? a. Species A b. Species B c. Species C d. Species E

d. Species E

37. Ephemerellid mayflies under attack by stoneflies will typically a. swim away to escape possible predation. b. rely on their cryptic coloration to escape detection. c. rely on their spiny appendages to deter attack. d. adopt a posture which increases their apparent size, so that the predator will avoid them. e. burrow into the stream bottom.

d. adopt a posture which increases their apparent size, so that the predator will avoid them.

4. Caghley found the distributions of the three largest kangaroo species in Australia are determined by a. hunting pressure. b. severe competition for den sites. c. severe predation. d. climate. e. All of the choices are correct.

d. climate.

99. The final theoretical stage of succession is called the _______ stage. a. omega b. ultimate c. penultimate d. climax

d. climax

8. Which of the following cannot be determined using a fecundity schedule combined with a life table? a. per capita rate of increase b. net reproductive rate c. mean generation time d. dispersal rates e. geometric rate of increase

d. dispersal rates

40. The __________ defines the physical conditions under which a species might live, in the absence of interaction with other species. a. functional niche b. realized niche c. principle niche d. fundamental niche e. primary niche

d. fundamental niche

14. If the age distribution diagram is bottom heavy or pyramidal in shape, this indicates that the population is a. stable. b. declining. c. growing slowly. d. growing rapidly. e. cannot be determined

d. growing rapidly.

34. Plagiorhynchus worms and Puccinia rusts are parasites that share the ability to change their host's behavior in way that a. increase the length of time they can survive in their hosts. b. decrease their host's mortality rates. c. increase their hosts reproduction, thereby increasing production of parasite-infected offspring. d. increase the likelihood of their (the parasites') transmission to a new host. e. decrease the hosts' vulnerability to other parasites.

d. increase the likelihood of their (the parasites') transmission to a new host.

61. The presence of a mutualist spider in a certain area improves the survival of an herbaceous shrub by reducing the impact of herbivorous insects. These spiders are preyed on by lizards, and lizards are eaten by birds. Reference: Ref 16-4 The removal of birds from the area would most likely have a(n) _______ effect on spiders and a(n) _______ effect on the plant. a. indirect positive; indirect positive b. indirect negative; indirect positive c. direct negative; direct negative d. indirect negative; indirect negative

d. indirect negative; indirect negative

29. Competition between members of a single species is called a. cohort specific competition. b. species specific competition. c. interspecific competition. d. intraspecific competition. e. interference competition.

d. intraspecific competition.

26. During droughts in the Galápagos Islands, the ground finches most likely to survive are those with a. smaller bodies. b. smaller bills. c. earlier maturation. d. larger bills. e. larger territories.

d. larger bills.

24. Gause's "competitive exclusion principle" states that a. when two species occur together, competition is always prevented by some behavioral adjustment. b. no two species can coexist indefinitely. c. no two competing species can coexist indefinitely. d. no two species with identical niches can coexist indefinitely. e. None of the choices are correct.

d. no two species with identical niches can coexist indefinitely.

23. In plants, "self-thinning" refers to reduction in a. the biomass of an individual in response to competition. b. the total biomass of a population in response to competition. c. both population density and population biomass in response to competition. d. population density in response to competition, as population biomass increases. e. population density due to grazing by herbivores.

d. population density in response to competition, as population biomass increases.

95. Sousa's studies of intertidal zones in southern California showed that a. succession was driven primarily by facilitation. b. the first species to colonize was the same across patches. c. the first species to colonize varied across patches. d. succession was driven primarily by inhibition.

d. succession was driven primarily by inhibition.

12. Density dependent factors include all of the following except: a. competition. b. disease. c. predation. d. temperature. e. None of the choices are correct.

d. temperature.

92. In their manipulative studies of succession in a New England salt marsh, Bertness and Shumway altered salt stress in certain fields by a. adding salt. b. introducing microbes that filter out salt. c. shading the soil's surface. d. watering the fields with fresh water.

d. watering the fields with fresh water.

3. Which of the following are characteristics of a population? a. consist of a single species b. have an age distribution c. have a birth rate d. have an emigration rate e. All of the choices are correct.

e. All of the choices are correct.

11. The factors that determine carrying capacity include all of the following except: a. space. b. disease. c. food. d. competition. e. None of the choices are correct.

e. None of the choices are correct.

16. Logistic population growth produces a __________ population growth curve. a. J-shaped b. K-shaped c. N-shaped d. R-shaped e. S-shaped

e. S-shaped

2. Research on North American bird populations have indicated that populations are _____________, distributed on a __________________ scale. a. clumped; small b. random; small c. regular; small d. regular; large e. clumped; large

e. clumped; large

19. Which of the following environments for germinating seed is most likely to favor a plant species that makes many small seeds, compared to one that makes fewer larger seeds? a. nutrient limitation b. competition from established plants c. shade d. deep burial in soil e. disturbance

e. disturbance

5. Type II survivorship curve indicates a. low juvenile mortality and high mortality in older adults. b. high juvenile mortality and low mortality in older adults. c. low juvenile mortality and low mortality in older adults. d. high juvenile mortality and high mortality in older adults. e. equal chance of dying at any age.

e. equal chance of dying at any age.

7. The age distribution of a population can reveal a. growth potential. b. survivorship. c. reproduction. d. both growth potential and survivorship. e. growth potential, survivorship and reproduction.

e. growth potential, survivorship and reproduction.

28. Two species occurring together in the same place are said to be a. competitors. b. precocial. c. mutualists. d. allopatric. e. sympatric.

e. sympatric.