[Maximum number: 2]
Wheat is a crop plant grown to produce flour.
(a)
Farmers grow crop plants such as wheat to provide food.
[ 2 ]
(i)
State two types of natural event that could cause widespread food shortages.
1
2
[ 2 ]
(a)
Intensive livestock production can be damaging to natural ecosystems.
Fig. 3.3 shows intensive farming of chickens.
[ 3 ]
(i)
Forests are cleared for farmland. Deforestation can lead to a loss of soil (soil erosion). Explain the effects of soil erosion on ecosystems.
[ 3 ]
(a)
Table 4.1 shows the number of hectares of forested area in some countries in Africa in the years 1990, 2000 and 2005.
Table 4.1
Calculate the percentage loss of forested area in Nigeria between 2000 and 2005.
Show your working and give your answer to the nearest whole number.
[ 2 ]
(b)
Describe the consequences of deforestation on the animals that live in forests.
[ 4 ]
(a)
(i)
Giant rats eat coconuts.
Coconuts are grown as a monoculture for human consumption.
Suggest how monocultures of crop plants can result in the extinction of some animals.
[ 3 ]
[Maximum number: 4]
Acid rain has destroyed many forests including the forest shown in Fig. 3.1.
Fig. 3.1
(a)
Explain the negative consequences to the environment of destroying forests.
[ 4 ]
[Maximum number: 1]
The graph shows how smoking different numbers of cigarettes for different lengths of time affects the risk of lung cancer.
Which conclusions are supported by the data in the graph?
1 Smoking more than 20 cigarettes per day always increases the risk of lung cancer more than smoking less than 20 cigarettes per day.
2 Smoking cigarettes for more years increases the risk of lung cancer.
3 Smoking more than 20 cigarettes per day for more than 50 years has the highest risk of lung cancer.
A
1, 2 and 3
B
1 and 2 only
C
1 and 3 only
D
2 and 3 only
[Maximum number: 3]
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.
Fig. 5.1
(a)
Explain the undesirable effects of deforestation on habitats that are on mountains, such as Mount Mulanje.
[ 3 ]
[Maximum number: 3]
Forest ecosystems are threatened by many human activities.
(a)
(i)
Describe reasons why people cut down forests.
[ 3 ]
[Maximum number: 9]
Fig. 5.1 shows an area of forest where some of the trees have been cut down.
Fig. 5.1
(a)
Explain the reasons why forests may be cut down as shown in Fig. 5.1.
[ 3 ]
(b)
Discuss the effects of deforestation on areas of land.
[ 6 ]
(a)
Fig. 6.1 shows the percentage of land covered by forest in a country from 1660 until 2000.
Fig. 6.1
[ 4 ]
(i)
Using the information in Fig. 6.1, state which 10-year period had the highest increase in the percentage of land covered by forest.
[ 1 ]
(ii)
Outline how human activities could cause the change in the percentage of land covered by forest from 1660 to 1800 shown in Fig. 6.1.
[ 3 ]