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UPSC IAS Prelims : Environment and Ecology : Ecosystem MCQs

May 12, 2015 16:10 IST

    1. On the Earth surface three abiotic systems are overlapping to form the realm of biotic system. The abiotic spheres are the atmosphere, hydrosphere, and lithosphere. The overlapping biotic sphere is called as ________?

     (a)Troposphere
     (b) Biosphere
     (c)Stratosphere
     (d) Mesosphere

    Answer .b

    2. Consider the following statements:

       1. Three-fourth of the earth surface is covered by water but less than 3% is fresh water used for human consumption.
       2. Of the total fresh water available, Ice-cap has highest share of 2% followed by ground water 0.68%.

    Select the correct answer using the code given below.

     (a) 1 only
     (b) 2 only
     (c) Both 1 and 2
     (d)  Neither 1 nor 2

    Answer .c

    3. Consider the following pairs:

           Personality                                   Concept/Term

    1.    Ernst Haeckel                                  Ecosystem
    2.    A.G. Tansley                                    Ecology
    3.    Elton                                               Ecological explosion

    Which of the above pairs are correctly matched?

       (a) 1 only
       (b) 2 and 3 only
       (c) 3 only
       (d) 1 and 2 only

    Answer .c

    4. Among these which is not an abiotic component of an ecosystem?

    (a)Climate
    (b)Water
    (c) Minerals
    (d) Microorganisms

    Answer .d

    5. Consider the following statements:

        1. Consumers are called as Autotrophs.
        2. The duration of sun exposure is the photo-period.
        3. Producers are also called as Heterotrophs.

    Which of the statements given above is/are correct?

      (a) 1 and 2 only
      (b) 2 only
      (c) 1, 2 and 3
      (d) 2 and 3 only

    Answer .b

    6. With reference to Chemosynthesis, consider the following statements:

       1. The synthesis of organic compounds from inorganic compounds using energy stored in inorganic substances such as sulphur, ammonia, and hydrogen. Energy is released when these substances are oxidised by certain organisms.
      2. Organisms at the bottom of oceans and in dark caves develop their food through the process of Chemosynthesis.

    Select the correct answer using the code given below.

    (a) 1 only
    (b) 2 only
    (c) Both 1 and 2
    (d) Neither 1 nor 2

    Answer .c

    7. With reference to productivity, consider the following statements:

       1. Primary production is defined as the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis.
       2. The rate of biomass production is called productivity.  

       3. Net primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis.
       4. Secondary productivity is defined as the rate of formation of new organic matter by consumers.

    Which of the statements given above is/are correct?

      (a) 1, 2 and 3 only
      (b) 1, 2 and 4 only
      (c) 1, 2, 3 and 4
      (d) 1 and 3 only

    Answer .b

    8. Choose the false statement among the following statements:

      (a) The productivity of the oceans is 110 billion tons as it occupies more than two-third of the surface.
      (b) The annual net primary productivity of the whole biosphere is approximately 170 billion tons (dry weight) of organic matter.
      (c) Primary productivity depends on the plant species inhabiting a particular area. It also depends on a variety of environmental factors, availability of nutrients and photosynthetic capacity of plants.
      (d) Gross primary productivity minus respiration losses, is the net primary productivity.

    Answer .a

    9. Plants and photosynthetic bacteria, fix suns’ radiant energy to make food from simple inorganic materials. Of the incident solar radiation less than 50 per cent of it is photosynthetically active radiation (PAR).Plants capture less than _____ percent of the PAR to sustain the entire world.

     (a) 40    
     (b) 30
     (c) 20
     (d) 10

    Answer .d

    10. With reference to detritus food chain (DFC), Consider the following statements:

       1. Decomposers are also known as saprotrophs.
       2. Dead plant remains such as leaves, bark, flowers and dead remains of animals, including fecal matter, constitute detritus.
       3.  Detritivores break down detritus into smaller particles. This process is called fragmentation.

    Select the correct answer using the code given below.

     (a) 1 and 2 only
     (b) 2 only
     (c) 1, 2 and 3
     (d)  2 and 3

    Answer .c

    For more IAS prelims Questions please click here

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