Chapter 26—Ecosystems Key
1. Ecology is
2. An example of a biotic component is
3. Which contains the largest number of organisms?
4. An ecosystem consists of
5. Which of the following represents an ecosystem that may be studied by an ecologist?
6. ____ dispersion usually results when plant roots produce substances that inhibit the growth of nearby plants.
7. An exponential growth curve
8. When you observe the growth of a population decreasing to zero, you can conclude that
9. A Type III survivorship curve would be observed
10. Interacting ecosystems form a
11. A metapopulation consists of
12. What kinds of organisms in an ecosystem are the producers?
13. Organisms which synthesize their own food using an inorganic energy source such as sunlight are called
14. What kinds of organisms in an ecosystem are the consumers?
15. Carnivores are
16. Herbivores are
17. Organisms that use the tissues of other organisms for food are called
18. An example of a detritivore is
19. Two important decomposers are
20. An organism’s niche includes
21. An organism’s habitat is
22. Intraspecific competition
23. A goat pulling a plant out of the ground to eat is an example of
24. A plant defense mechanism to escape predation includes
25. Mutualism is a type of
26. The type of symbiotic relationship where one symbiont benefits and the other is harmed is called
27. The symbiotic relationships in nature are all the result of
28. An example of commensalism is
29. Keystone species
30. Which of the following is an example of primary succession?
31. Which of the following statements about succession is FALSE?
32. An example of a pioneer organism is a
33. The energy for most communities comes from
34. Which of the following is NOT recycled?
35. Which of the following statements about ecosystems is FALSE?
36. In a food chain, a secondary consumer is
37. Which of the following organisms would be at the first trophic level in a food chain?
38. The complex of interconnected food chains in an ecosystem is known as
39. Which of the following organisms would be found at the base of a pyramid of energy?
40. In the carbon cycle, carbon is returned to the water and atmosphere of the abiotic environment by
41. Carbon is taken from the atmosphere and bound into organic molecules through
42. Nitrogen is taken from the atmosphere and converted into a form usable by plants through a process called
43. In the nitrogen cycle, ____ is the term used when plant roots absorb either ammonia or nitrate from the soil.
44. Which process causes a loss of nitrogen from the soil because of bacterial activity?
45. Nitrogen-fixing bacteria are found
46. Nitrification
47. Which of the following statements about the nitrogen cycle is false?
48. Which of the following statements concerning nitrogen fixation is FALSE?
49. The hydrologic cycle involves
50. Which is an example of top-down regulation of ecosystems?
51. An ecosystem is a community plus its environment.
52. The most common type of dispersion is random dispersion.
53. A population can exhibit a J-shaped growth curve indefinitely.
54. Type I survivorship is observed when mortality is concentrated later in life.
55. Consumers that eat only producers are called omnivores.
56. Detritus feeders are consumers that feed on dead organic matter such as leaf litter and feces.
57. Interspecific competition affects population size and sometimes results in one or more species being
eliminated from an area.
58. Symbiotic relationships are always beneficial to the organisms involved.
59. The type of symbiotic relationship where both symbionts are benefited is called commensalism.
60. Keystone species are usually the dominant species.
61. The Earth is essentially a closed system, from which matter cannot normally escape.
62. The passage of energy in an ecosystem from one organism to the next in sequence is known as a food
chain.
63. As energy moves from one trophic level to the next, some of the energy is lost as heat.
64. Primary consumers occupy the base of a pyramid of energy.
65. The location of most of the Earth’s carbon is the atmosphere.
66. Bacteria perform four of the five steps in the nitrogen cycle.
67. Members of the same species that live together in the same area at the same time are called a(n)
____________________.
68. All the communities on Earth, taken together, are considered the ____________________.