2nd Year Biology Chapter 25 Ecosystem Notes MCQs Bank Solution

biology 12th notes chapter 25

1. Biome is a large:

 
 
 
 

2. On an annual basis, approximately what percentage of all the CO₂ in the atmosphere is fixed by photosynthesis?

 
 
 
 

3. Natural selection has led to the evolution of diverse natural history strategies.Which of the following characteristics do these different natural history strategies have in common?

 
 
 
 

4. What percentage of sun’s available energy do the plants capture, while the other trophic levels captures approximately

 
 
 
 

5. Which of the following pyramids can never be inverted in a natural ecosystem?

 
 
 
 

6. Which of the following chemicals enters living organisms primarily from the atmosphere rather than from rocks or soil?

 
 
 
 

7. Which one of the followings would be a detritivore?

 
 
 
 

8. The term niche was first proposed by

 
 
 
 

9. One of the followings do not feed on grasses

 
 
 
 

10. A molecule of nitrogen which you have just breathed in may have been part of a plant that lived thousands of years ago, or part of a dinosaur that lived millions of years ago.This illustrates the principle that

 
 
 
 

11. To measure the population density of monarch butterflies occupying a particular park, 100 butterflies are captured, marked with a small dot on a wing, and then released.The next day, another 100 butterflies are captured, including the recapture of 20 marked butterflies.One would correctly estimate the population to be

 
 
 
 

12. The pattern of dispersion for a certain species of kelp is clumped.The pattern of dispersion for a certain species of snail that lives only on this kelp would likely be

 
 
 
 

13. Net productivity is the gross productivity less that which is consumed by the producers in metabolism.Which of the followings does not contribute to the species diversity of the tropics?

 
 
 
 

14. Charles Eton defined the niche as the species’:

 
 
 
 

15. A group of interbreeding individuals, belonging to same species and sharing a common geographic area, is called

 
 
 
 

16. Many individuals of the same species living together in a defined area form

 
 
 
 

17. The category “detritivore” includes decomposers as well as scavengers.In a salt marsh, the meiofauna

 
 
 
 

18. Major regional ecological community of plants and animals forms

 
 
 
 

19. Nitrogen gas returns to the atmosphere by the action of

 
 
 
 

20. What type of organism carries out nitrogen fixation?

 
 
 
 

21. Which of the following levels of organization is arranged in the correct sequence starting from most to least inclusive?

 
 
 
 

22. Lichens are an example of

 
 
 
 

23. Lithosphere includes

 
 
 
 

24. Root nodules

 
 
 
 

25. Organisms in trophic level 3 are

 
 
 
 

26. Study of single population relationship to its environment is called

 
 
 
 

27. Mutualism

 
 
 
 

28. The total amount of energy that is converted to organic compounds in a given area per unit of time is called the

 
 
 
 

29. Consider the following list of factors
I.Dispersal II.Rainfall
III.Mineral deposits IV.Competition
V.Temperature
Which of the factors listed above are most significant in determining the fact that belts of vegetation at successively higher altitudes often correspond to those at successively higher latitudes?

 
 
 
 

30. While studying the community we come across following levels of integration

 
 
 
 

31. When two different species overlap in the same biological niche, they are

 
 
 
 

32. Which of the following terms best describes the inter-relationship between nitrogen-fixing bacteria and the clover in whose roots they live?

 
 
 
 

33. In each case succession is initiated by a few hardy invaders called:

 
 
 
 

34. The organisms which obtain their energy from the dead and decaying plants and animals are called

 
 
 
 

35. Biological communities change because

 
 
 
 

36. A short food chain of two or three links supports a community

 
 
 
 

37. Fungi causing dandruff is an example of

 
 
 
 

38. A localized group of individuals belonging to the same species is called as:

 
 
 
 

39. Which of the followings are producers?

 
 
 
 

40. The distinct levels or link of food chain are called:

 
 
 
 

41. In which of the following habitats would you expect to find the largest number of K-selected individuals?

 
 
 
 

42. Which of the followings is characteristic of parasitism?

 
 
 
 

43. Which of the followings is an example of Batesian mimicry?

 
 
 
 

44. The conversion of atmospheric free nitrogen gas to ammonia occurs through the activities of certain bacteria and cyanobacteria

 
 
 
 

45. The accumulation of herbivore biomass in an ecosystem is an example of

 
 
 
 

46. Biosphere is spread out over the surface of planet earth extending about

 
 
 
 

47. Problems with ground water include slow movement, increasing use rate, and increasing rate of pollution.The term “detritivore” includes

 
 
 
 

48. The bacteria living in the root nodules of the legume plants serve to fix atmospheric?

 
 
 
 

49. The abiotic component of an ecosystem is

 
 
 
 

50. Diseases in living organisms caused by parasites are called:

 
 
 
 

51. Carbon dioxide makes up approximately what percentage of the atmosphere?

 
 
 
 

52. A change in the community, structure of an ecosystem over a period of time is:

 
 
 
 

53. What is happening to the amount of carbon dioxide in the atmosphere?

 
 
 
 

54. The branch of biology which deals with the study of relationship between organism and their environment

 
 
 
 

55. Resource partitioning would be most likely to occur between

 
 
 
 

56. Which of the following communities is the most productive?

 
 
 
 

57. Which of the followings is a secondary consumer?

 
 
 
 

58. Nitrogen makes following percent of gases in atmosphere

 
 
 
 

59. One of the followings is not the primary form of succession

 
 
 
 

60. Which trophic level is incorrectly defined?

 
 
 
 

61. A population is correctly defined as having which of the following characteristics?
I.Inhabiting the same general area
II.Individuals belonging to the same species
III.Possessing a constant and uniform density and dispersion

 
 
 
 

62. All of the followings act to increase species diversity except

 
 
 
 

63. The earth is an open system with respect to

 
 
 
 

64. The legume plants, pea and bean are the hosts

 
 
 
 

65. Which of the following organisms is a primary consumer?

 
 
 
 

66. C.Eton defined the Niche as the species

 
 
 
 

67. Once nitrate enters the plant cell it is reduced as:

 
 
 
 

68. All populations within an ecosystem are known as:

 
 
 
 

69. On an average, for a crop plant to produce one kilogram of food it requires how many kilograms of water?

 
 
 
 

70. Two barnacles, Balanus and Chthamalus, can both survive on the lower rocks just above the low tide line on the Scottish coast, but only Balanus actually does so, with Chthamalus living in a higher zone.Which of the followings is the most likely cause of this niche separation?

 
 
 
 

71. Pond

 
 
 
 

72. As energy is transferred from one trophic level to next following percent of energy is lost

 
 
 
 

73. Study of relationship of different communities to environment is called:

 
 
 
 

74. In a terrestrial ecosystem, the trophic level that would contain the largest biomass would be the

 
 
 
 

75. The actual location of place where an organism lives is called its:

 
 
 
 

76. If a meteor impact or volcanic eruption injected a lot of dust into the atmosphere and reduced sunlight reaching Earth’s surface by 70 percent for one year, all of the following communities would be greatly affected except a

 
 
 
 

77. Dry habitat

 
 
 
 

78. The process in which micro-organisms use the proteins and amino acids and release ammonia of ammonium ions known as

 
 
 
 

79. The hydrologic cycle is driven primarily by

 
 
 
 

80. All of the statements regarding models of logistic population growth are correct except

 
 
 
 

81. Which of the followings is not a problem with ground water?

 
 
 
 

82. Species transplant experiments are one way of determining

 
 
 
 

83. An association between two organisms by which both are benefited is called

 
 
 
 

84. Carnivores represent what trophic level?

 
 
 
 

85. In the past decade, which of the followings has not been a major cause of the increase in the world’s population?

 
 
 
 

86. All of the following can contribute to density-dependent regulation of population except

 
 
 
 

87. Owl

 
 
 
 

88. Which of the followings contains a lot of carbon?

 
 
 
 

89. Several bacteria in the soil are able to oxidize ammonia or ammonium ions, this oxidation is known as:

 
 
 
 

90. Joseph Grinnel

 
 
 
 

91. Which of the following statements is most consistent with the interactive hypothesis?

 
 
 
 

92. What is true of turnover rates of chemicals in ecosystems?

 
 
 
 

93. Goats depend on autotrophs for the production of

 
 
 
 

94. The sequence of energy flow through a food chain is

 
 
 
 

95. Energy from sun flows through an ecosystem in the form of:

 
 
 
 

96. “Owls prey on rabbits and mice”, this is an example of

 
 
 
 

97. The process of converting nitrate to nitrogen gas and nitrous oxide is called

 
 
 
 

98. Dry soi

 
 
 
 

99. A carrot plant is exposed to carbon dioxide containing radioactive carbon for 24 hours.After this exposure, the carrot roots are found to have accumulated radioactivity.These carrots are then fed to a rabbit.One week later, the rabbit’s tissue is tested for radioactivity and is found to have a higher than normal background count.Which biogeochemical cycle is apparent from this study?

 
 
 
 

100. Biotic component

 
 
 
 

101. Some water, a small amount of soil, a few green aquatic plants and a fish were placed in a large bottle.The bottle was scaled to prevent the exchange of gases and other materials between its contents and the outside.The bottle was placed in a window to receive light during the daytime.Is carbon dioxide produced by the plants?

 
 
 
 

102. Insects

 
 
 
 

103. One of the followings is not a biotic factor

 
 
 
 

104. Mycorrhiza

 
 
 
 

105. When bacteria in oxidize ammonia or ammonium ions, this is called:

 
 
 
 

106. The major reservoir for phosphorus is

 
 
 
 

107. Foliage lichen

 
 
 
 

108. Who defined the niche as the species occupation?

 
 
 
 

109. Bacteria in the root nodules fix nitrogen and convert it into:

 
 
 
 

110. The progressive series of changes that eventually produce a climax community on wheat was once a bare rocky island is an example of

 
 
 
 

111. During the growth of a tomato plant from a seed, it increases considerably in biomass.Which of the following materials, obtained from the environment, are necessary for the growth and increase in biomass?

 
 
 
 

112. Carrying capacity

 
 
 
 

113. Primary Succession starting in a pond is called:

 
 
 
 

114. The rate of growth of a natural population

 
 
 
 

115. Net primary productivity is the gross primary productivity less

 
 
 
 

116. The amount of energy actually incorporated into the biomass of phototrophs is

 
 
 
 

117. Dermatocarpon is an example of

 
 
 
 

118. All the food chains and food webs begin with

 
 
 
 

119. Eagle

 
 
 
 

120. Ecology

 
 
 
 

121. In 1917, term niche was first proposed by American Ornithologist named

 
 
 
 

122. Study of a single population relationship to its environment is called as

 
 
 
 

123. Autecology

 
 
 
 

124. Abiotic component

 
 
 
 

125. Of the fresh water in the United States, 96 percent consists of

 
 
 
 

126. Following percent of total energy from the sun is trapped by the producers in an ecosystem

 
 
 
 

127. The total energy from sun trapped by producer in an ecosystem is;

 
 
 
 

128. Lichens are dual organism composed of symbiotic association of

 
 
 
 

129. Evidence shows that some grasses benefit from being grazed.Which of the following terms would best describe this plant-herbivore interaction?

 
 
 
 

130. Net primary production

 
 
 
 

Short Questions

1. Briefly write about secondary succession.
2. Define and describe biotic components of an ecosystem.
3. Define Assimilation?
4. Define biogeochemical cycles. What are biogeochemical cycles?
5. Define biosphere. What is biosphere. Define biosphere and ecosystem.
6. Define commensalism.Give one example. Define commensalism with the help of an example.
7. Define ecological niche according to Charles Eton.
8. Define ecology?
9. Define ecosystem.Write its components. Define ecosystem.
10. Define environment?
11. Define exosystem?
12. Define food chain and food web. Define food chain by giving an example.
13. Define grazing?
14. Define habitat?
15. Define Niche?
16. Define oecologic or ecology?
17. Define parasitism.Give its significance. Differentiate between predation and parasitism.
18. Define Parasitism?
19. Define predation. Give the significance of predation.
20. Define Predation?
21. Define producers?
22. Define productivity of an ecosystem and differentiate between gross primary production and net primary production.
23. Define Secondary succession?
24. Define succession and name its types.
25. Define Succession?
26. Define synecology or community ecology.
27. Define the environment?
28. Define the term ecosystem?
29. Describe food chain?
30. Differentiate between actoparasite and endoparasite?
31. Differentiate between autecology and synecology. What is synecology? What is autecology?
32. Differentiate between autecology and synecology?
33. Differentiate between Biotic and A-biotic components?
34. Differentiate between consumers and decomposers. What are consumers?
35. Differentiate between derosere and hydrosere?
36. Differentiate between food chain and food web?
37. Differentiate between habitat and niche. Define niche. Explain ecological niche.
38. Differentiate between habitat and niche?
39. Differentiate between hydrosere and xerosere.
40. Differentiate between micro and macro nutrients?
41. Differentiate between Mutualism and commensalism?
42. Differentiate between population and community.
43. Differentiate between predator and prey?
44. Differentiate between primary and secondary succession. How primary succession differ from secondary succession?
45. Explain biosphere (ecosphere).What are its limits?
46. Give definition of autecology.
47. Give some examples of predator-prey cycle?
48. Give the similarities between the following: i) Root nodules and Mycorrhiza.ii) Mutualism and Lichens.iii) Parasitism and Cormmensalism.
49. How does food web help maintain stability of the ecosystem?
50. How many basic interaction components of exosystem are there?
51. Name different stages of Xerosere?
52. Name some ways of nitrogen depletion from soil and its remedy.
53. Name the biotic (living) and the abiotic (non-living) components of the ecosystem?
54. Name the levels of integration that we come across while studying the community?
55. Name the three main ecological components of the abiotic world.
56. Name the various possible trophic levels (food links) in an ecosystem?
57. Suggest alternative names for primary, secondary and tertiary consumer animals?
58. What are biogenic elemetns?
59. What are biogeochemical cycles?
60. What are consumers?
61. What are decomposers? Quote examples?
62. What are Lichens?
63. What are Micronutrients?
64. What are Producers?
65. What are Root Nodules?
66. What are the main components of an ecosystem?
67. What are the three principal stages of nitrogen cycle?
68. What aree infestations?
69. What constitutes planetary ecosystem?
70. What does ornithology mean?
71. What does pioneer community mean in plant succession?
72. What ecological terms are used for air water and soil?
73. What is a biome? Quote examples?
74. What is a population?
75. What is a predator?
76. What is ammonification?
77. What is assimilation?
78. What is autecology?
79. What is biomass?
80. What is biome?
81. What is biome? Differentiate between biome and biosphere?
82. What is biosphere?
83. What is Denitrification?
84. What is food web in an ecosystem?
85. What is grazing? How grazing affect the texture of soil? Define grazing.How grazers affect the ecosystem?
86. What is meant by a community in the ecosystem?
87. What is mycorrhiza?
88. What is Nitrification?
89. What is nitrogen cycle?
90. What is phytoplankton?
91. What is Primary succession?
92. What is succession in ecology?
93. What is Symbiosis?
94. What is the term ecology derived from?
95. What is Xerosere?
96. What percentage of sun energy reaches to plants?
97. Who proposed the term niche in ecology and when?
98. Who used the term ecology for the first time and when?
99. Why nutrient cycles are called biogeochemical cycles?

Long Questions

1. Define ecosystem. Describe various components of an ecosystem.
2. Define succession.Explain the different stages of xerosere. Explain the stages of xerosere. Describe different stages of succession in xerosere.
“3. Define the following terms
(i)- Habitat (ii)- Niche (iii)- Food web (iv)- Succession. “
4. Define the following terms i) Habitat ii) Niche iii) Food Web iv) Succession
5. Define Xerosere. Describe its different stages.
6. Describe nitrogen cycle.
7. Describe predation and parasitism and their significance.
8. Differentiate between biotic and abiotic components and describe different types of biotic component of an ecosystem.
9. Discuss the flow of energy in food chain of an ecosystem.
10. Explain the biotic component of an ecosystem.
11. Explain the biotic component of an ecosystem.
12. What is biogeochemical cycle? Explain nitrogen cycle?
13. What is food web? How it is constructed to show various trophic levels?
14. What is symbiosis? Explain its types with examples.
15. Write a note on grazing.
16. Write a note on nitrogen cycle.
17. Write a short note on Grazing.

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