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Which one of the following is the best description of the term ‘ecosystem’?

(a)

A community of organisms interacting with one another

(b)

That part of the Earth which is inhabited by living organisms

(c)

A community of organisms together with the environment in which they live

(d)

The flora and fauna of a geographical area

Correct Answer

(c)

Explanation

An ecosystem is a community of living organisms in conjunction with the non-living components of their environment, interacting as a system. These biotic and abiotic components are regarded as linked together through nutrient cycles and energy flows.Tikdam: organism + environment + their interaction

Microtheme: Ecological Theory —
17 questions asked in Prelims in the past.

  1. [2017] Biological Oxygen Demand (BOD) is a standard criterion for

    • (a) Measuring oxygen levels in blood
    • (b) Computing oxygen levels in forest ecosystems
    • (c) Pollution assay in aquatic ecosystems
    • (d) Assessing oxygen levels in high altitude regions
    Correct Answer: (C) Pollution assay in aquatic ecosystems
  2. [2015] Which one of the following is the best description of the term ‘ecosystem’?

    • (a) A community of organisms interacting with one another
    • (b) That part of the Earth which is inhabited by living organisms
    • (c) A community of organisms together with the environment in which they live
    • (d) The flora and fauna of a geographical area
    Correct Answer: (C) A community of organisms together with the environment in which they live
  3. [2014] Which one of the following is the correct sequence of a food chain?

    • (a) Diatoms-Crustaceans-Herrings
    • (b) Crustaceans-Diatoms-Herrings
    • (c) Diatoms-Herrings-Crustaceans
    • (d) Crustaceans-Herrings-Diatom
    Correct Answer: (A) Diatoms-Crustaceans-Herrings
  4. [2014] Which one of the following is the process involved in photosynthesis?

    • (a) Potential energy is released to form free energy.
    • (b) Free energy is converted into potential energy and stored.
    • (c) Food is oxidized to release carbon dioxide and water.
    • (d) Oxygen is taken, and carbon dioxide and water vapour are given out.
    Correct Answer: (B) Free energy is converted into potential energy and stored.
  5. [2013] With reference to the food chains in ecosystems, which of the following kinds of organism is/are
    known as decomposer organism/organisms?
    1.Virus
    2.Fungi
    3.Bacteria
    Select the correct answer using the codes given below.

    • (a) 1 only
    • (b) 2 and 3 only
    • (c) 1 and 3 only
    • (d) 1, 2 and 3
    Correct Answer: (B) 2 and 3 only
  6. [2013] Which one of the following terms describes not only the physical space occupied by an
    organism, but also its functional role in the community of organisms?

    • (a) Ecotone
    • (b) Ecological niche
    • (c) Habitat
    • (d) Home range
    Correct Answer: (B) Ecological niche
  7. [2013] In the grasslands, trees do not replace the grasses as a part of an eological succession because
    of

    • (a) insects and fungi
    • (b) limited sunlight and paucity of nutrients
    • (c) water limits and fire
    • (d) None of the above
    Correct Answer: (C) water limits and fire
  8. [2013] Which one of the following is the correct sequence of ecosystems in the order of decreasing
    productivity?

    • (a) Oceans, lakes, grasslands, mangroves
    • (b) Mangroves, oceans, grasslands, lakes
    • (c) Mangroves, grasslands, lakes, oceans
    • (d) Oceans, mangroves, lake, grasslands
    Correct Answer: (C) Mangroves, grasslands, lakes, oceans
  9. [2013] With reference to food chains in ecosystems, consider the following statements :
    (1). A food chain illustrates the order in which a chain of organisms feed upon each other.
    (2). Food chains are found within the populations of a species.
    (3). A food chain illustrates the numbers of each organism which are eaten by others.
    Which of the statements given above is/are correct?

    • (a) 1 only
    • (b) 1 and 2 only
    • (c) 1, 2 and 3
    • (d) None
    Correct Answer: (A) 1 only
  10. [2011] Consider the following:
    1. Photosynthesis
    2. Respiration
    3. Decay of organic matter
    4. Volcanic action
    Which of the above add carbon dioxide to the carbon cycle on earth?

    • (a) 1 and 4 only
    • (b) 2 and 3 only
    • (c) 2, 3 and 4 only
    • (d) 1, 2 ,3 and 4
    Correct Answer: (C) 2, 3 and 4 only
  11. [2011] Consider the following statements: 1. Biodiversity is normally greater in the lower latitudes as compared to the higher latitudes. 2. Along the mountain gradients, biodiversity is normally greater in the lower altitudes as compared to the higher altitudes. Which of the statements given above is/are correct?

    • (a) 1 only
    • (b) 2 only
    • (c) Both 1 and 2
    • (d) Neither 1 nor 2
    Correct Answer: (C) Both 1 and 2
  12. [2011] Biodiversity forms the basis for human existence in the following ways:
    1. Soil formation
    2. Prevention of soil erosion
    3. Recycling of waste
    4. Pollination of crops
    Select the correct answer using the code given below:

    • (a) 1, 2, and 3 only
    • (b) 2, 3, and 4 only
    • (c) 1 and 4 only
    • (d) 1, 2, 3 and 4 only
    Correct Answer: (D) 1, 2, 3 and 4 only
  13. [2010] Some species of plants are insectivorous. Why?

    • (a) Their growth in shady and dark places does not allow them to undertake sufficient photosynthesis and thus they depend on insects for nutrition.
    • (b) They are adapted to grow in nitrogen deficient soils and thus depend on insects for sufficient nitrogenous nutrition.
    • (c) They cannot synthesize certain vitamins themselves and depend on the insects digested by them.
    • (d) They have remained in that particular stage of evolution as living fossils a link between autotrophs and heterotrophs.
    Correct Answer: (B) They are adapted to grow in nitrogen deficient soils and thus depend on insects for sufficient nitrogenous nutrition.
  14. [2010] Sustainable development is described as the development that meets the needs of the present without compromising the ability of future generations to meet their own needs. In this perspective, inherently the concept of sustainable development is intertwined with which of the following concepts?

    • (a) Social Justice and Empowerment
    • (b) Inclusive Growth
    • (c) Globalization
    • (d) Carrying capacity
    Correct Answer: (D) Carrying capacity
  15. [2010] From the point of view of evolution of living organisms, which one of the following is the correct sequence of evolution?

    • (a) Otter-Tortoise-Shark
    • (b) Shark-Tortoise-Otter
    • (c) Tortoise-Shark-Otter
    • (d) Shark-Otter-Tortoise
    Correct Answer: (B) Shark-Tortoise-Otter
  16. [2010] A pesticide which is a chlorinated hydrocarbon is sprayed on a food crop. The food chain is: Food crop – Rat -Snake – Hawk. In this food chain, the highest concentration of the pesticide would accumulate in which one of the following?

    • (a) Food crop
    • (b) Rat
    • (c) Snake
    • (d) Hawk
    Correct Answer: (D) Hawk
  17. [2009] With reference to the evolution of living organisms, which one of the following sequences is correct ?

    • (a) Octopus-Dolphin-Shark
    • (b) Pangolin-Tortoise-Hawk
    • (c) Salamander-Python-Kangaroo
    • (d) Frog-Crab-Prawn
    Correct Answer: (C) Salamander-Python-Kangaroo