Biodiversity & the Effect of Human Interaction on Ecosystems (AQA GCSE Biology: Combined Science)

Exam Questions

2 hours15 questions
1a2 marks

Draw a ring around the most appropriate word from each of the square brackets to complete the sentence. 

A highly biodiverse ecosystem is [stable / large / successful] because of the

number of [competing / complementary / interdependent] species it contains.

1b1 mark

Which of A - D is most likely to lead to a biodiverse ecosystem?

  • A large number of unconnected food chains

  • A large number of interconnected food chains

  • A small number of unconnected food chains

  • A small number of interconnected food chains

1c1 mark

Figure 1 shows a food web from a marine ecosystem.

Figure 1

food-web---sea-2

Suggest an effect on this ecosystem if the fish were removed by human activity (too much commercial fishing).

1d2 marks

Identify the producer species in Figure 1.

1e1 mark

Which of the factors A - D is not likely to have a negative impact on biodiversity of the marine ecosystem shown in Figure 1?

  • Human introduction of more lobsters into the area

  • Global warming

  • Sewage ingress into the sea

  • Imposition of fishing quotas

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2a1 mark

Choose the row of Table 1 that gives the combination of factors that would lead to an increased amount of human waste being produced. 

Table 1

+ means increasing       - means decreasing

  Standard of Living Population  Life expectancy
A + + +
B - + +
C - - +
D - - -

    2b2 marks

    Give two ways in which pollution can reduce biodiversity.

    2c2 marks

    Figure 2 shows a number of pollutants and the ways that they affect ecosystems.

    Figure 2

    pollution-q-1

    Draw a straight line to match each pollutant with the effect that it creates. 

    2d
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    2 marks

    Pesticide levels in the water of a lake were measured at a level of 877 parts per billion.

    The same pesticide was measured in the gills of a fish living in that lake and showed biomagnification by a factor of 9.75 million (9 750 000) times.

    Calculate the concentration of the pesticide in the fish's gills. Give your answer in standard form. 

    2e1 mark

    Question 2d) gives an example of biomagnification, in which the level of a dangerous compound gets higher at successive trophic levels. 

    Explain how biomagnification differs from bioaccumulation. 

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    3a
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    3 marks

    Figure 3 shows a map of a piece of land with its usage in the years 1600 A.D and 2000 A.D.

    Figure 3

    land-use-16002000-1

     

    Use Figure 3 to complete the missing values in the table below.

    land-use-table

    3b
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    2 marks

    Calculate the percentage decrease in mature woodland area between 1600 and 2000 A.D.

    3c2 marks

    Describe how the removal of woodland areas can have a bad effect on other organisms.

    3d2 marks

    Give two reasons why forests are being cut down.

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    4a2 marks

    Give two reasons why deforestation is contributing to an increase in atmospheric CO2 levels.

    4b1 mark

    Which of A - D is not a possible consequence of global warming?

    • Changes in migration patterns of birds.

    • Sea level rise.

    • Increase in fossil fuel regeneration. 

    • Habitat loss for certain animals. 

    4c2 marks

    State and explain the action that carbon dioxide (CO2) and methane (CH4) both have on the atmosphere that causes them to be greenhouses gases. 

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    5a3 marks

    Suggest three measures that governments can take to maintain levels of biodiversity.

    5b2 marks

    In some countries, conservationists and other groups may disagree about how land is used.

    Name one such group of people and state why they may disagree with conservationists.

    5c2 marks

    One popular and cost-effective measure that farmers can take to promote biodiversity is the use of field margins.

    Describe what a field margin is and how it increases biodiversity. 

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    1a1 mark

    Malaysia is a country in South-East Asia located near the equator.

    Malaysia is one of the 17 megadiverse countries recognised by Conservation International, with a high level of biodiversity and many endemic species.

    Describe what is meant by the term ‘biodiversity’.

    1b4 marks

    Malaysia has one of the world’s highest rates of deforestation.

    Since 2000, Malaysia has lost over 14% of its tropical rainforest.

    The land is either cleared to grow crops to produce palm oil, or to raise livestock for meat production.

    Explain how deforestation impacts the concentration of carbon dioxide in the atmosphere.

    1c6 marks

    Monoculture is the agricultural practice of growing one particular species (a crop plant or livestock animals) in an area.

    Malaysia is the world’s biggest exporter of palm oil which is mainly used for biofuel production, and for many farmers it provides an essential source of income.

    Palm oil monoculture in Malaysia is causing much concern amongst environmentalists, not least due to the loss of habitat and because farmers rely on chemical fertilisers to improve the quality of soil.

    Evaluate the benefits and risks of growing monoculture crops.

    Give a conclusion in your answer.

    1d2 marks

    There is a growing level of concern about how human activity and population growth are affecting biodiversity.

    Suggest why it is important that we maintain a high level of biodiversity. 

    1e2 marks

    Describe two ways in which the negative effects of humans on biodiversity and the ecosystem can be reduced.

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    2a2 marks

    Deforestation is a major contributor to the general decline of biodiversity worldwide. 

    Suggest two ways in which deforestation impact biodiversity negatively. 

    2b4 marks

    With an increased need for food security due to a rapidly increasing population, farmers are keen to maximise their crop yields. 

    One way in which they can achieve this is to prevent the growth of weeds using plant growth hormones. 

    Evaluate the use of plant growth hormones by farmers, considering the impact of such hormones on biodiversity.

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    3a3 marks

    There is a general consensus amongst the scientific community that increased levels of carbon dioxide emissions as a result of human activity are causing global warming due to an enhanced greenhouse effect. 

    Explain how increases in the proportions of greenhouse gases in the atmosphere have led to global warming.

    3b2 marks

    Global warming, and the climate change that it brings, have an overall detrimental effect on biodiversity and ecology in general.

    Suggest and explain one effect of global warming that may be beneficial to an individual species.

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    4a6 marks

    Peat bogs are areas of wetland that contain partially-decomposed plant material (peat). 

    The conditions in a peat bog are usually acidic, which is one of the reasons why the decay of plant material is so slow (forming peat). 

    Peat is an excellent natural fertiliser. 

    Suggest why the destruction of peat bogs is controversial. 

    4b
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    3 marks

    Data from the United Nations suggests that globally, we are losing 88,000 km2 of natural forest every year to timber and paper production, and to clearance of land for crops and livestock grazing.

    A football pitch has an area of 7 140 m2.

    Calculate the time taken, at the current rate of deforestation, for a football pitch-sized piece of land to be deforested. Give your answer to the nearest whole second. 

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    5a2 marks

    Humans are reducing the area of land available for other living species. 

    Give two ways in which humans are doing this. 

    5b2 marks

    Growth in demand for biofuel has led to large areas of rainforest being cleared in South America to grow sugarcane. 

    Sucrose is extracted from sugarcane and is fermented by microorganisms to produce ethanol, which is used in biofuels for cars.

    The graph in Figure 1 shows how the production of sugarcane has changed for one country in South America. 

    sugarcane

    Calculate the percentage change in sugarcane growth over a 10 year period between 2007 and 2017.

    Show clearly how you have worked out your answer. 

    5c5 marks

    Clearing rainforests to create sugarcane plantations to produce biofuels for cars is controversial, with some scientists arguing that biofuels are not carbon neutral. 

    Explain why. 

    5d6 marks

    Almost 70% of the world’s almond supply is grown in California. 

    Intensive farming of almonds in California has decreased the quality of the soil. 

    To combat this, and to meet demand, farmers are increasingly reliant on fertilisers.

    Excess fertiliser ends up running off into rivers and streams. 

    Suggest the consequences of excess fertiliser ending up in the water supply. 

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    1a
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    1 mark

    The graph in Figure 1 shows the area of forest land lost in Ecuador in the years 2014 - 2019 inclusive. 

    Figure 1

    ecuador-deforestation-1

    Determine the total area of land lost to deforestation in Ecuador from the beginning of 2014 to the end of 2019. 

    1b2 marks

    Identify (in Table 1 below) the possible reasons for the change in the area of forest lost per year between 2014 and 2017.

    Place a tick (✔) in the boxes below that apply.

    Table 1

    The local people stop growing maize  
    Less new house-building is needed for the population  
    The local people decided to farm sheep and goats  
    More trees have been planted  
    A company starts growing sugar cane for the production of biofuel  



    1c2 marks

    Suggest two explanations for the reductions in loss of forest land in Ecuador in the years 2018 and 2019. 

    1d2 marks

    Government officials looked at the graph shown in Fig. 1 in late 2019 and concluded that the forest was starting to recover.

    Explain why this conclusion may be incorrect. 

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    2a2 marks

    Deforestation causes an increase in the level of carbon dioxide (CO2) in the atmosphere.

    Give two reasons why.

    2b6 marks

    A dairy farmer hoses down the floors of his milking shed at the end of each day's milking. The effluent flows from the shed floor and is pumped into a waste water storage tank. The effluent contains urine and faeces from the cattle.

    On one occasion, the effluent overflows his waste water storage tank and finds its way into a nearby stream.

    Explain the effect that the effluent will have on the plants and animals living in the stream.

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    3a
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    2 marks

    The oil palm is a tree that grows in tropical areas, whose oil has many uses in cooking, food preparation and as a detergent. It is also used in the manufacture of biofuels. Figure 2 shows the annual production of palm oil in Colombia (South America) since 2010. 

    Figure 2

    palm-oil-production---colombia-2

    Calculate the mean increase in palm oil production per year for the three year period 2014 to 2017. Show clearly how you work out your answer.

    Give your answer in thousands of metric tonnes per year.

    3b5 marks

    The replacement of forests with oil palm plantations to produce biofuels will change the composition of the atmosphere.

    Explain how.

    3c1 mark

    When palm oil plantations are created, native forest is cut down and the biodiversity in the forest reduces dramatically. Even when demand for palm oil is low, there is still a benefit to the palm oil manufacturers in cutting down the native forest.

    Suggest what that benefit is. 

    3d1 mark

    Conservationists concerned about the loss of habitats caused by oil palm plantations are urging farmers to use methods that allow humans to take what they need from the land but to do so in a way that oil palms can coexist with native species.

    What is the name of this kind of farming?

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    4a
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    4 marks

    Table 2 gives data about how the carbon dioxide (CO2) concentration of the air has changed over time. 

    Year CO2 concentration in parts per million
    1800 282
    1900 295
    1950 310
    2000 370
    2020 410
    2022 420

    Plot the data from Table 2 in the graph paper provided below. blank-graph-paper-7x8-big-squares

    4b3 marks

    Explain why carbon dioxide concentrations in the atmosphere are changing.

    4c
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    2 marks

    In 2022, a climate activist claimed that, to arrest global warming, the atmospheric CO2 level should be brought back to the level of the year 1900.

    Using the data from Table 2, calculate the percentage decrease that the climate activist claims would be needed to return the atmospheric CO2 level to its 1900 level. 

    4d2 marks

    Figure 3 shows some damage to a piece of furniture caused by woodworm. 

    Figure 3

    woodworm-damage-1

    Describe how the action of woodworm can contribute to global warming. 

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    5a2 marks

    When fossil fuels are burned, they release carbon dioxide (CO2) into the atmosphere. In addition, because they contain levels of sulfur, sulfur dioxide gas (SO2) can also be released into the atmosphere. 

    Flue gases from the burning process can be captured and desulfurised, which traps the flue gases and reacts the sulfur dioxide with calcium hydroxide. 

    Ca(OH)2(s) + SO2(g) → CaSO3(s) + H2O(l)

    A further step results in the formation of calcium sulfate which is a major component of plasterboard used in the building industry. 

    Apart from supplying the building industry, state and explain the advantage of the process of flue gas desulfurisation. 

    5b2 marks

    Another product of burning fossil fuels, especially the heavier fractions of crude oil like diesel, are so-called particulates

    Explain what particulates are and describe their detrimental effect on people who come into contact with them. 

    5c6 marks

    There are currently two main ways in which domestic trash is disposed of by local authorities in the UK. These are:

    1. Landfill
    2. Incineration (burned at 1000°C)

    Table 3 below outlines some of the features of both ways of disposing of trash. 

    Table 3

    Landfill Incineration
    Traditional, trusted More recent method
    Needs a large hole in the ground eg. a disused quarry Involves a high-tech incineration plant
    Generates CO2 and methane Generates a lot of CO2
    Causes odours and insect/rat infestations Clean-burning; few pollutants emitted to the atmosphere/rivers
    Requires waste to be transported a long way, even exported Generates heat and electricity for the local grid
    Suitable sites running out Unpopular but effective
      Can be set up in all localities

    Use the data in Table 3 and your knowledge of waste treatment to evaluate both methods of waste disposal and to recommend a policy to a UK local authority. 

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