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DP IB Biology: HL

Topic Questions

Home / IB / Biology: HL / DP / Topic Questions / 4. Ecology / 4.2 Carbon Cycling & Climate Change / Structured Questions: Paper 2


4.2 Carbon Cycling & Climate Change

Question 1a

Marks: 1
a)

Methane (CH4) is a simple hydrocarbon gas present in the atmosphere or underground as part of natural gas fossil fuel. A group of single-celled organisms, called archaeans, can produce methane by means of different mechanisms.

State the name of the process by which methane is produced.

[1 mark]

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    Key Concepts
    Methanogenesis

    Question 1b

    Marks: 2
    b)

    Archaeans can produce methane in a range of different environments.

    List two of these environments where methane can be produced.

    [2 marks]

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      Key Concepts
      Methanogenesis

      Question 1c

      Marks: 1
      c)

      When methane is released into the atmosphere, it is involved in the following reaction:7Td-ipoa_e-1c

      Identify the type of reaction that is illustrated above.

      [1 mark]

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        Key Concepts
        Oxidation of Methane

        Question 1d

        Marks: 2
        d)

        Carbon compounds, such as methane, can become trapped in peat which can be burned as fuel.

        Briefly describe how peat is formed.

        [2 marks]

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          Key Concepts
          Formation of Peat

          Question 2a

          Marks: 1
          a)

          Many marine animals, such as mussels and corals, extract carbon from their surroundings to produce hard body parts such as shells.

          State the chemical substance that these hard body parts consist of.

          [1 mark]

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            Key Concepts
            Limestone Formation

            Question 2b

            Marks: 2
            b)

            Describe the process by which the hard body parts of marine organisms, such as molluscs and corals, can become a carbon store.

            [2 marks]

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              Key Concepts
              Limestone Formation

              Question 2c

              Marks: 2
              c)

              The following table shows the atmospheric carbon dioxide levels over time.

              Year Carbon dioxide concentration / ppm
              1960 316
              1970 325
              1980 338
              1990 354
              2000 369
              2010 387

              Calculate the percentage increase in carbon dioxide concentration between 1960 and 2010. Record your answer to one decimal place.

              [2 marks]

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                Question 2d

                Marks: 1
                d)

                Atmospheric carbon dioxide levels have shown a dramatic increase since the industrial revolution.

                State the main reason for this increase.

                [1 mark]

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                  Question 3a

                  Marks: 2
                  a)

                  Carbon dioxide is an example of a greenhouse gas.

                  Define the term 'greenhouse gas'.

                  [2 marks]

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                    Question 3b

                    Marks: 2
                    b)

                    List two other examples of greenhouse gases, other than carbon dioxide.

                    [2 marks]

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                      Question 3c

                      Marks: 2
                      c)

                      The impact of greenhouse gas in the atmosphere can vary considerably.

                      State two factors that determine the significance of the impact that a greenhouse gas can have.

                      [2 marks]

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                        Key Concepts
                        Greenhouse Effect

                        Question 4a

                        Marks: 3
                        a)
                        Study the diagram below.Z_t94isP_e-4a

                        i)
                        State the name of the process illustrated by the diagram.

                        [1 mark]

                        ii)
                        Label the type of radiation represented by A and B in the diagram.

                        [2 marks]

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                          Key Concepts
                          Greenhouse Effect

                          Question 4b

                          Marks: 1
                          b)

                          Greenhouse gases, especially carbon dioxide, have increased in the atmosphere over the past few decades.

                          State the effect this increase in greenhouse gases will have on global average temperatures.

                          [1 mark]

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                            Question 4c

                            Marks: 2
                            c)

                            List two possible impacts on climate patterns caused by the change in global temperatures described in part (b).

                            [2 marks]

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                              Question 5a

                              Marks: 4

                              One mark is available for clarity of communication throughout this question.

                              a)

                              Describe the role of autotrophs within the carbon cycle.

                              [4 marks]

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                                Question 5b

                                Marks: 4
                                b)

                                There are several processes in the carbon cycle that increase the levels of carbon dioxide in the atmosphere.

                                List two of these processes and state how they increase carbon dioxide levels in the atmosphere.

                                [4 marks]

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                                  Question 5c

                                  Marks: 7
                                  c)

                                  Increased carbon dioxide levels in the atmosphere are having an effect on ocean chemistry.

                                  Outline the way in which atmospheric carbon dioxide affects the pH of oceans and how this change may impact marine organisms.

                                  [7 marks]

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