Human Influences on the Environment (Edexcel GCSE Biology)

Figure 1 shows a river and the location of a fertiliser factory. The arrows indicate the direction of the flow of the river.

Figure 1

A scientist recorded the nitrate concentrations of the water at site A and site B. Her results are shown in the table.

Higher Tier Only

Scientists observe living organisms in an environment to assess the level of pollution.

Describe how the level of water pollution and air pollution can be assessed using living organisms.

Higher Tier Only

Suggest why levels of pollution cannot always be accurately determined using indicator species as described in part (b).

Higher Tier Only

Figure 1 shows some information about three different species of lichen.

Figure 1

Explain which one of these species is most likely to be found near a coal burning power station.

Higher Tier Only

Figure 4 show the presence of organisms in six lakes. 

Each lake has a different pH. 

The bars show if a particular organism is present at a certain pH.  

Water pollution can be caused by an increase in nitrates and phosphates.

Explain the problems associated with an increase of nitrates and phosphates levels in a lake.

Higher Tier Only

A group of students investigated the level of pollution in two different streams, A and B. Figure 1 shows the students results.

Figure 1

Use of indicator species to monitor and control pollution is a key tool for maintaining biodiversity.

Tayrona National Park is a popular nature attraction in Colombia. It receives around half a million visitors per year. Dung beetles are used by ecologists in the park as an indicator of the impact that human activities has on the biodiversity of the area.

Outline the economic benefits of maintaining biodiversity in a national park such as Tayrona.

The size of the dung beetle popultation in Tayrona National Park showed a significant negative impact of human activity to the biodiversity of the area.

Suggest a suitable conservation method to protect and maintain the species in this ecosystem.

Figure 1 shows a salmon fish farm in the sea.

Figure 1

Complete the Figure 2 to provide a solution to each of the problems associated with farming fish in fisheries.

Higher Tier Only

Figure 1 shows changes in the abundance of several invertebrate species in a river as distance from a sewage outflow increases.

Figure 1

Describe the data shown in Figure 1.

Higher Tier Only

The Tubificidae are a family of aquatic worms, such as sludge worms, while Chironomus are a family of flies, the larvae of which are blood red in colour.

Use this information to explain what Figure 1 shows about the effects of sewage in freshwater habitats.

Higher Tier Only

Give two examples of organisms that could fall within the group of invertebrates described in Figure 1 as 'clean water species'.

Higher Tier Only

A worker from an environmental charity viewed the data in Figure 1 and concluded that sewage release lowers oxygen levels in freshwater habitats.

Evaluate this conclusion.

Figure 1 shows the mass of fish caught by traditional fishing and produced by fish farming between 1970 and 2023 in three countries; country M, country N and country O.

Figure 1

Compare and contrast the changes in the mass of fish caught by traditional fishing and the mass of fish produced by fish farming from 1970 to 2023.

Calculate the percentage increase in fish production by fish farming in country M between 1970 and 2023.

Explain how each of the following aspects of fish farming might affect biodiversity:

Many fish are kept together in large enclosures within a lake or area of ocean.

(2)

(ii)

Carnivorous fish species are fed food that contains fish from wild populations.

(1)

Farmed fish may escape from their enclosures.

(1)

Table 1 contains information about the occurrence of two species of crayfish at different river sites in the UK between the 1960s and the early 2000s.

Table 1

The data in Table 1 were collected by repeated sampling at 26 different sites over several decades.

Explain the importance of sampling in this type of investigation.

(2)

(ii)

Suggest three factors that the researchers undertaking the sampling would have needed to control over the extended period of the investigation.

(3)

Use the data in Table 1 to complete Table 2 below.

(2)

Use the graph paper provided to draw a graph to represent the data in Table 2.

(3)

Suggest which of the two crayfish species represented in Table 1 and Table 2 is not indigenous to the UK.

(1)

(ii)

Explain your answer to part (i).

(2)

The Rivers Trust has introduced advice designed to reduce the damage caused by non-indigenous crayfish in the UK.

One piece of advice given to river users in the UK is to ensure that boats, shoes and equipment are thoroughly cleaned between uses.

Suggest how this may help to reduce crayfish damage.

(2)

(ii)

Another measure taken has involved trapping and removing crayfish. This often results in the removal of larger crayfish while leaving smaller individuals behind.

Suggest how this measure may result in an increase in crayfish numbers.

(1)