Lesson 7 Community ecology

Transcription

1 Lesson 7 Community ecology 1. The concept of trophic structure of a community emphasized the a. prevalent form of vegetation. b. keystone predator. c. feeding relationships within a community. d. effects of coevolution. e. species richness of the community. 2. According to the concept of competitive exclusion, a. two species cannot coexist in the same habitat. b. extinction or emigration are the only possible results of competitive interactions. c. competition within a population results in the success of the best-adapted individuals. d. two species cannot share the exact same niche in a community. e. resource partitioning will allow a species to utilize all the resources of its niche. 3. The effect of a keystone predator within a community may be to a. competitively exclude other predators from the community. b. maintain species diversity by preying on the prey species that is the dominant competitor. c. increase the relative abundance of other predators. d. encourage the coevolution of predator and prey adaptations. e. create nonequilibrium in species diversity. 4. Food chains are relatively short in communities because a. two herbivore species may not feed on the same plant species. b. local extinction of one species dooms all the other species in a food web. c. energy is lost as it passes from one trophic level to the next higher level. d. very few predatory species have evolved. e. most plant species are inedible. 5. According to the rivet model of community organization, a. two closely related species cannot coexist in the same community. b. extinction is rare in well-organized communities. c. species can be easily replaced if one should be driven extinct by human actions. d. all species in a natural community contribute to its integrity. e. communities are loosely structured groups of individualistic species with similar abiotic requirements. 6. An example of cryptic coloration is the a. green color of a plant. b. bright markings of a poisonous tropical frog. c. stripes of a skunk. d. mottled coloring of moths that rest on lichens. e. bright colors of a insect-pollinated flower. 7. An example of Müllerian mimicry is a. a butterfly that resembles a leaf. b. two poisonous frogs that resemble each other in coloration. c. a minnow with spots that look like large eyes. d. a beetle that resembles a scorpion. e. a carnivorous fish with a wormlike tongue that lures prey.

2 8. Which of the following is the best explanation for the finding that equatorial (tropical) regions have the greatest species richness? a. the species-area curve that predicts high richness in large areas. b. a climate with high levels of solar radiation and water availability. c. the increased speed of speciation due to higher temperatures in the region. d. the inverse relationship between evapotranspiration and biodiversity. e. the greater immigration rate and lower extinction rate found on large tropical islands close to the mainland. 9. According to the hypothesis of island biogeography, species richness would be greatest on an island that is a. small and remote. b. large and remote. c. large and close to a mainland. d. small and close to a mainland. e. environmentally homogeneous. 10. In the process called species act as agents of natural selection on each other. a. succession b. commensalism c. competition d. symbiosis e. coevolution 11. Which of the following is not a major category of interspecific or intraspecific interaction among organisms? a. Symbiosis b. Predation c. Competition d. Speciation e. Mutualism 12. The biologist who studies interactions at the "community" level investigates interactions between a. Organisms of one species b. Organisms of more than one species c. Animals of one species d. Social animals (like insects) e. Ecosystems 13. If you were studying the niche of a species of bird, you might study a. The food it eats b. Its predators c. The temperatures it needs to survive d. The places where it builds its nests e. All of these 14. Which of the following is the best way to define an ecological niche? a. The physical environmental factors needed for survival b. The organism's home or habitat c. An organism's interactions with predators and prey species d. All the aspects of an organism's way of life e. The intraspecific behavior of the species 15. An ecological niche a. Is formed by the physical environment only b. Depends on the weather

3 c. Is a constantly changing place d. Cannot be shared by two species e. Is the same thing as its habitat 16. Competition between members of two species is a. Very intense, and referred to as intraspecific b. Most intense when the species are most similar, and referred to as interspecific c. Very unusual, and referred to as interspecific d. Very common, and referred to as intraspecific e. Least intense between similar species, and referred to as interspecific 17. Two species that have a high degree of niche overlap, will a. Compete intensely b. Speciate c. Interbreed d. Be a predator-prey pair e. Coexist peacefully 18. If similar species each occupy a smaller niche when they live together than they would if they lived alone, they are said to be a. Involved in succession b. Involved in intraspecific competition c. Partitioning their resources d. Coevolving e. Increasing niche overlap 19. The concept that two species cannot occupy the same ecological niche is a. Coevolution b. Mutualism c. Succession d. Competitive exclusion principle e. Commensalism 20. In interspecific competition, a. both species benefit from the interaction because each species expands its ecological niche b. both species are harmed because access to resources is reduced c. one species is harmed because only one species can expand its ecological niche d. either a or b may be true e. either a or c may be true 21. Two species of buttercup can be found in the same field in South Dakota, however, they emerge at different times: one species emerges and flowers in early spring, and the other species does not emerge until the late summer, after the first species has set seed. This is likely to be an example of a. competitive exclusion b. niche fragmentation c. niche realignment d. resource partitioning e. interspecific competition 22. Two species of buttercup can be found in a field in North Dakota, and they tend to flower at the same approximate time in early spring. When some ecology students decide to conduct an experiment in community dynamics, they selectively remove one species from the field by hand picking all emergent plants. When the one species is removed, the other species shows a significant increase in its population the next season. This study demonstrates a. competitive exclusion b. niche fragmentation

4 c. niche realignment d. resource partitioning e. interspecific competition 23. Choose one of the following kinds of organisms and name as many aspects of its niche as you can think of: a. Bear b. Oak tree c. Crabgrass in your yard d. Grasshopper e. Rattlesnake 24. If an insect eats the lettuce seedlings in your yard, it is acting most like a a. parasite b. host c. mutualist d. commensalist e. herbivore 25. If you find a brightly colored insect resting on a dead leaf, it is likely to a. Be poisonous or distasteful b. Be prey for birds c. Be camouflaged d. Have startle coloration e. Have aggressive mimicry 26. Which of the following statements best describes the reason why bright coloration is an effective defense against predators? a. The predators are color blind and cannot see the prey. b. The predators can see the color and, either through natural selection (if the prey is toxic) or learning (if the prey is merely unpalatable), avoid the prey. c. Predatory animals are too stupid to learn anything; thus color is unimportant. d. Symbiosis allows predators to coexist with prey so that neither go extinct. e. Commensal relationships such as this are the result of coevolution. 27. An effective, bright and very distinct color pattern that can be displayed suddenly by a prey species to scare a predator is a. Modelling b. Aggressive mimicry c. Mimicry d. Startle coloration e. Camouflage 28. Which of these describes an effective means that prey species may use to evade predators? a. Mimicry b. Warning coloration c. Chemical warfare d. Startle coloration e. All of these 29. Which of these might a predator use to enable it to catch its prey? a. Startle coloration b. Warning coloration c. Camouflage d. Symbiosis e. Coevolution

5 30. Which behavioral response to the threat of predation is most likely to be selected for in a species that uses camouflage for protection from predators? a. A quick escape response b. Sudden display to startle the predator c. Cooperative behavior d. Behavior that mimics the behavior of the predator e. Motionless behavior 31. Trees often produce secondary chemicals to deter herbivores from feeding on their leaves; in turn, many herbivores have produced ways of avoiding or detoxifying these chemicals. This is an example of a. competitive exclusion b. predatory avoidance c. coevolution d. parasitic evolution e. parasite predation 32. The term mimicry may refer to a. prey species imitating the predators b. nontoxic prey imitation toxic prey c. predators imitating harmless parts of the environment d. a and b but not c e. a, b, and c 33. A close interaction between organisms of two different species which is beneficial to one of the organisms but has no effect on the survival of the other is a. Mutualism b. Commensalism c. Parasitism d. Mimicry e. Symbiosis 34. In its broadest sense, symbiosis includes which of the following relationships between organisms of two different species? a. Mutualism, predation, commensalism b. Mutualism, predation, parasitism c. Predation, commensalism, parasitism d. Mutualism, commensalism, parasitism e. Mutualism, commensalism, competition 35. Which of the following are NOT an example of two organisms in a mutualistic relationship? a. Humans and malaria protozoan b. Flowering plants and pollinators c. Ants and acacias d. Clown fish and sea anemone e. Nitrogen-fixing bacteria and legumes 36. Which of the following is NOT an example of two organisms in a parasitic relationship? a. Carnivorous plant and the insect it captures b. Human Immunodeficiency Virus (the AIDS virus) and an infected human c. Lamprey eel and the fish whose blood it feeds on d. Tapeworm and the goat whose digestive tract it lives in e. Flea and the cat it feeds on 37. What characteristic best distinguishes predators from parasites? a. Predators feed on large animals, parasites attack small organisms

6 b. Predators are long-lived, parasites are short-lived c. Predators kill their hosts immediately, parasites usually do not kill their hosts immediately d. Predators attack both healthy and weak organisms, parasites attack primarily weakened or old organisms e. Predators always harm their prey, parasites have a mutualistic relationship with their hosts 38. Tapeworms in the human gut are an example of a. predators b. parasites c. hosts d. commensalists e. prey 39. Sap-feeding insects that feed on pants may be classified as a. predators b. parasites c. hosts d. commensalists e. prey 40. Many plants are mycorrhizal, where their roots are infected with a specialized fungus. The plant supplies carbon to the fungus, and the fungus supplies nutrients to the plant. Mycorrhizae are an example of a association. a. mutualistic b. commensalistic c. parasitic d. successional e. predator/prey 41. A species that plays a major role in determining the structure of its ecological community is: a. A predator b. A dominator species c. The most abundant species in the community d. A keystone species e. The largest species 42. The African elephant is considered to be a keystone species because: a. Removal of elephants from their community would result in drastic changes in the ecological structure of the community b. It is the largest organism in its community c. Elephants live in large cooperative herds that dominate other smaller groups within the community d. Elephants eat more food than any other species in their community e. Elephant populations are larger than any other populations of organisms in their community 43. When all vegetation is removed from a site by human activity or by natural forces such as volcanic activity, species are the first to colonize the site. a. prokaryotic b. pioneer c. climax d. deciduous e. eukaryotic

7 44. Which of the following is not true of the general trend from recently disturbed to stable self-sustaining community? a. An increase in depth and organic content of soil occurs. b. Long lived species become dominant in the community. c. Productivity increases. d. The rate at which populations replace each other increases. e. All of the choices above are true of a community that is developing towards a climax community. 45. Succession which begins on bare rock after glaciers have passed, or on newly formed volcanic islands is a. Primary b. Secondary c. Allogenic d. Pioneer e. Autogenic 46. A sand dune in Georgia might take several years to reach a climax community, whereas a former corn field that has been left unfarmed is likely to take a couple of years to reach the same climax. a. hundred; hundred b. thousand; hundred c. thousand; thousand d. hundred; thousand e. million; thousand 47. The first plant community that forms on bare rock often has organisms such as a. Herbs, conifers b. Grasses, weeds c. Broad-leaf trees, conifers d. Lichens, moss e. Woody shrubs, conifers 48. When succession occurs after a field is abandoned in the southeastern U.S., the rich soil and intense sunlight allow fast-growing species such as to thrive. a. ragweed and crabgrass b. mosses c. pine trees d. oaks and maples e. tulip poplars and sweetgum 49. Which of the following statements is true of climax communities? a. All areas will have the same climax community if enough time is allowed for succession. b. The climax community which develops is determined by many factors such as temperature, rainfall, elevation and type of rock. c. The climax community at a site changes rapidly. d. As the earth gets older the area covered by climax communities is increasing. e. Climax communities are made up of all the species that were found in each successional community. 50. After a forested area such as a national forest is clear cut, what type of succession occurs? a. Primary b. Secondary c. Subclimax d. Climax e. Biome

8 51. The next time you need to mow the grass, you can excuse yourself on the basis that by mowing you are helping to maintain the system in a man-made. a. climax b. subclimax c. biome d. community e. population 52. When a community like the tallgrass prairie is maintained by regular disturbances such as periodic fires set by Native Americans or by lightning, a community exists. a. taiga b. subclimax c. climax d. chaparral e. deciduous 53. The term "exotic" to a biologist means: a. an unusual species in a tropical environment b. a particularly beautiful species c. a species that has been introduced into a different ecosystem from the one in which it evolved d. a very desirable species cultivated for the benefit of humans e. an extinct species 54. What ecological process changes a lake to a marsh over a long period of time? a. Eutrophication b. Competitive exclusion c. Succession d. Extinction e. Coevolution 55. Which of the following is NOT a concern with the introduction of an exotic species into a non-native ecosystem? a. Displacement of native species b. Rapid spread of the exotic species from the introduction area to other areas c. Alteration of the ecosystem d. Alteration of the climate e. Predation on native species by the exotic species Essay 56. Kudzu, a leguminous vine native to Japan, is considered an exotic invader in this country but not in its native habitat. In many parts of the United States, kudzu is rapidly expanding and outcompeting native species. Why might this be so? 57. Several ecology students were tracking the population ranges of two species of squirrels that live in the Cascade range of Oregon. These students noted that when both species of squirrels were present in a region, species A could be found from sea level to about 900 feet above sea level, and species B could be found from about 900 feet to 1500 feet above sea level. However, when species B was found alone, then it had a range of about 500 feet to 1500 feet. Why might this be true? 58. Write a paragraph comparing the color (or lack of color) that you would most likely see on an insect that is poisonous with one that is a slow-moving prey for birds. Explain why there are such differences. 59. There are several species of plain-looking, brownish-grey moths which when they spread their wings have large bright red or orange eye-shaped circles on their hind wings. What is this called and what advantage does it give to the moth?

9 60. In what ways are Pseudomyrmex ants and bull's-horn acacias dependent on each other? What type of interspecific interaction is this? 61. Most bacteria can reproduce very quickly, hence their populations can rapidly increase. Describe the evolutionary process which prevents most human disease-causing bacterial parasites from causing the human population to become extinct. 62. You suspect that the American alligator is a keystone species in specific habitats in Florida. How might you experimentally prove or disprove this hypothesis? 63. What kind of species are likely to be pioneers in secondary succession? Explain why. 64. After forest harvest in an old-growth forest of the Oregon Cascades, ecologist noted that the species that were present after 5 years differed from the species that were present 25 year laterääand these differed from the species that were present 75 years later. What are the general characteristics of the species at each stage, and why does the community change over time? 65. Fire is increasingly used as a management tool in both forest and grassland ecosystem to increase species diversity. How might fire influence the occurrence of a climax community and species diversity?