Human Impact: Biodiversity, Pollution & Conservation (Cambridge (CIE) IGCSE Biology): Exam Questions

The chimpanzee lives in forests in central and western Africa. The chimpanzee is classified as an endangered species because its population has decreased greatly. 

(i)

Suggest why the chimpanzee population has decreased.

[2]

(ii)

Describe how a captive breeding programme can help to conserve chimpanzees in the wild.

[2]

(iii)

State two methods, other than captive breeding, of conserving endangered species.

[2]

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. 

(i)

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

[2]

(ii)

State the name of one process that removes carbon dioxide from the atmosphere.

[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

(i)

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

[2]

(ii)

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

[1]

(iii)

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

[1]

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.

(i)

State two other undesirable effects of deforestation.

[2]

(ii)

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

[2]

The forests in Brazil contain many endangered species.

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

Table 1

(i)

Calculate the average area of forest removed per year from 2006 to 2010.

Give your answer in km². Show your working.

[2]

(ii)

Describe the trend in the data shown in Table 1.

[1]

(iii)

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

[2]

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

(i)

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

[1]

(ii)

List three undesirable effects of habitat destruction.

[3]

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

Researchers investigated the effect of adding cattle manure (cattle faeces) to fields where snap bean plants, Phaseolus vulgaris, were grown. Cattle manure contains some protein.

Explain how protein in the cattle manure is converted to the type of ions that plants can absorb.

Snap bean plants are legumes which have root nodules that contain nitrogen‑fixing bacteria.

Fig. 4.1 shows some root nodules.

(i)

Suggest the advantage to farmers of having snap bean plants that have a large number of root nodules.

[1]

(ii)

The researchers investigated the effect of adding cattle manure to fields of snap bean plants.

• Field 1 was treated with a small quantity of cattle manure.

• Field 2 was treated with a medium quantity of cattle manure.

• Field 3 was treated with a large quantity of cattle manure.

• Field 4 was not treated with any cattle manure.

The researchers counted the number of root nodules on samples of plants from each field when the snap beans were harvested.

The results of the investigation are shown in Fig. 4.2

Calculate the percentage increase in the average number of root nodules per plant when snap bean plants were grown with a large quantity of cattle manure (field 3) compared with no cattle manure (field 4).

Give your answer to two significant figures.

Space for working.

[3]

(iii)

When large quantities of manure are put on fields it can lead to eutrophication of streams and rivers. This can lead to the death of fish.

Describe how eutrophication of streams and rivers can lead to the death of fish.

[4]

The Mulanje cedar, Widdringtonia whytei, is the national tree of Malawi. This species of tree grows naturally only on Mount Mulanje in Malawi. Many of the trees have been overharvested or destroyed by wildfires, resulting in deforestation, as shown in Fig. 5.1.

State the genus name of the Mulanje cedar tree.

Explain the undesirable effects of deforestation on habitats that are on mountains, such as Mount Mulanje.

Scientists in Malawi are working to prevent the extinction of the Mulanje cedar tree in its natural habitat.

Explain the benefits to other organisms on Mount Mulanje of conserving the Mulanje cedar tree in its natural habitat.

The seeds of many endangered tree species are kept in seed banks.

Suggest why it is important to collect seeds from many individual trees of each species rather than just one tree.

Intensive livestock production is used to improve food production. 

Describe the negative effects of intensive livestock production.

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

Fig. 1

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

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

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

Conservationists looking at the data in Fig. 1 would not be fully satisfied with the 2018 - 2019 trend shown in the data.

Explain why. 

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.

Large quantities of plastic waste are polluting the oceans. 

A survey published in March 2018 showed the increase in plastic waste in the Pacific Ocean. One area of the Pacific Ocean is known as the Great Pacific Garbage Patch (GPGP). 

Data were collected from areas inside and outside the GPGP between 1965 and 2015 to estimate the quantity of plastic waste. 

The results are shown in Fig. 2.1.

Describe the results of the survey shown in Fig. 2.1.  

The green turtle, Chelonia mydas, is a species of marine animal that is harmed by plastic waste. 

Fig. 2.2 shows a green turtle swimming past a plastic bag in the Pacific Ocean.

(i) Turtles are classified as reptiles. 

State one feature shown by all reptiles that is not found in amphibians. 

[1]

(ii) Outline the dangers of non-biodegradable plastic waste to marine animals, such as green turtles. 

[4]

(iii) Suggest ways to reduce the quantity of plastic waste.

[2]