20.1 Human Impact: Biodiversity, Pollution & Conservation

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

Fig. 1

A scientist recorded the nitrate concentrations of the water at site A and site B. 

Table 1 shows the results of this investigation.

Table 1

Calculate the percentage difference in the mean nitrate concentration between site A and B.

Show your working and state the nature of the difference.

Extended only

Scientists observed algae and dead fish at site B.

Suggest an explanation for these observations.

Explain the importance of using chemical fertiliser in modern farming practices.

Further tests revealed that the water at site B contained abnormally high levels of cadmium, which is a heavy metal. After analysing the remains of aquatic organisms from the site, the top carnivores were found to have a very high concentration of cadmium stored in their fat cells.

Suggest the risk of high levels of cadmium to the river ecosystem.

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.

Fig. 1 shows the annual production of palm oil in Colombia (South America) since 2010. 

Fig. 1

Calculate the mean increase in palm oil production per year for the three year period 2014 to 2017.

Show your working and give your answer in thousands of metric tonnes per year.

Biofuels produced from palm oil can be used as a more renewable alternative to fossil fuels. However, the replacement of forests with oil palm plantations to produce biofuels will change the composition of the atmosphere.

Explain how.

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. 

Growing trees for palm oil is an example of monoculture farming.

Explain three disadvantages of monoculture farming.

Extended Only

There are many threats to species such as the marine iguana.

Describe ways endangered plant and animal species can be conserved.

The energy we use comes from a variety of sources. 

Fig. 1 shows the percentage of each source of energy used in one country in 2011. 

Fig. 1

Coal, natural gas and oil are types of fossil fuel.

Calculate the total percentage of energy in Fig. 1 that came from fossil fuels.

Explain why fossil fuels are not sustainable resources.

Combustion of fossil fuels releases carbon dioxide into the atmosphere. 

State the name of two other processes that release carbon dioxide into the atmosphere.

[2]

[1]

Describe the effects on the environment of increasing carbon dioxide concentration in the atmosphere. 

Improvements in food production have allowed human populations to increase.

Describe how modern technology has increased the production of crop plants. 

Fig. 1 shows part of the carbon cycle. Some of the arrows are missing.

Fig. 1

State all the letters in Fig. 1 that represent respiration.

[2]

State the name of the process that the letter J represents.

Draw an arrow on Fig. 1 to represent the process of feeding.

Carbon dioxide is a greenhouse gas.

State the name of one other greenhouse gas.

Deforestation can cause an increase in the concentration of carbon dioxide in the atmosphere.

State two other undesirable effects of deforestation.

[2]

State two uses for land that has been cleared of trees.

Table 1 shows the area of forest that was removed in Brazil each year between 2006–2010.

Table 1

Give your answer in km². Show your working.

[2]

Describe the trend in the data shown in Table 1.

Suggest two reasons for the trend you have described in part (ii).

Some animals are farmed intensively.

Describe the negative impacts to an ecosystem of intensive livestock production.

State why fertilisers, herbicides and insecticides are used in farming.

Fertilisers, herbicides and insecticides can all pollute water.

List two other sources of water pollution.

Extended Only

There are many threats to wildlife in the Galapagos.

Describe ways in which endangered species can be conserved.

Extended Only

One aim of conservation is to maintain resources in natural ecosystems.

State three resources that natural ecosystems provide for humans.

Fig. 1 shows a photograph of an area where the trees have been cut down.

Fig. 1

State the name of the type of habitat destruction shown in Fig. 1.

[1]

State three human activities, other than cutting down large areas of trees, that can cause habitat destruction.

Describe how endangered species can be conserved.

Human activity can cause pollution of the environment.

Table 1 shows some pollutants, the environment they pollute and some of the effects.

Complete Table 1.

Table 1