O-LevelGeographyThe natural environment2217/13 · Oct/Nov 2011 · Q425 Marks

Study Fig. 6, which shows annual average precipitation in west Africa. Estimate the annual average precipitation at Agades. mm

(a)(i)Study Fig. 6, which shows annual average precipitation in west Africa. Estimate the annual average precipitation at Agades. mm[1]
(a)(ii)Suggest why daytime temperatures are high at Agades.[2]
(a)(iii)Explain why rainfall is low in areas such as Agades.[3]
(b)(i)Study Fig. 7, which shows information about rainfall in Agades. Agades is in Niger (an LEDC). Describe three features of the rainfall distribution over the five years shown by Fig. 7.[3]
(b)(ii)Suggest how the rainfall distribution shown in Fig. 7 may affect the lives of people living in and around Agades.[4]
(b)(iii)The area around Agades is at risk from desertification. This can be defined as 'the spread of desert-like conditions into nearby regions'. Explain why desertification occurs.[5]
(c)For a named area of tropical desert which you have studied, describe the features of the natural vegetation and explain how it can survive in the desert climate. Tropical Desert studied[7]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2011). The mark or mark type is shown in brackets.

[1] 51- 199
[2] Ideas such as:
Low latitude/near Equator;
High angle of sun/sun overhead;
Lack of cloud/direct sunlight etc.
[3] Ideas such as:
Long way from sea/ocean/inland;
Winds blow overland;
Lack of evaporation/no plants to give off water;
High pressure;
Rain shadow etc.
[3] Ideas such as:
uneven distribution;
highest in Years 2/3;
lowest in Year 5;
rain falls April – September;
August is wettest month;
No rainfall October – February (March);
Increases up to Year 3 and decreases after that etc.
[4] Ideas such as:
insufficient water for domestic use (Oct – Feb/March);
they will need to store water;
they may suffer dehydration;
or have to walk long distances to collect water;
they will not be able to water crops (Oct – Feb/March);
yields may be low/less food supply;
possible starvation/malnutrition/people die;
herds of animals may need to be moved to better pasture/nomadic lifestyle/animals die;
incomes vary through the year;
flooding in times of high rainfall (August);
crops are washed away;
causing soil erosion;
limited supplies of water used may be polluted and carry disease etc.
[5] Ideas such as:
Less rainfall/drought/long period without rain;
Chopping down trees/deforestation;
To use for firewood (dev);
Loss of nutrients in soil;
Over grazing of animals;
Use of land for agriculture in marginal areas/on edge of desert;
Global warming;
Sun bakes the soil/makes cracks in soil etc.
[7] Level 1 (1-3 marks)
Statements including limited detail describing and/or explaining characteristics of natural vegetation of tropical desert.
(e.g. scattered/sparse vegetation, seeds/plants only flower/grow for short periods, narrow/ spiky leaves, long roots/wide spreading roots search for water, some plants store water, plants grow around oases etc.)
Level 2 (4-6 marks)
Uses named example
More developed statements describing and explaining characteristics of natural vegetation of tropical desert.
(e.g. Low precipitation/aridity results in scattered/sparse vegetation, seeds/plants remain dormant during long dry spells, narrow/spiky leaves reduce rates of evapotranspiration because of high temperatures, long roots/wide spreading roots search for water as it is so dry; little cover of soil/sand/bare rock surfaces so few plants grow; some plants/cacti store water in order to survive long periods of drought, plants grow around oases where water is available etc.)
(NB MAX 5 if no named example)
Level 3 (7 marks)
Uses named example (e.g. Sahara Desert).
Comprehensive and accurate statements describing and explaining characteristics of natural vegetation of tropical desert, including some specific reference to place or species of plants.
(e.g. Low precipitation/aridity results in scattered/sparse vegetation, Joshua Tree remains dormant during long dry spells, narrow/spiky leaves reduce rates of evapotranspiration because of high temperatures, creosote bush has long roots/wide spreading roots search for water as it is so dry; little cover of soils and bare rock surfaces so few plants grow; xerophytes/saguaro cactus stores water in order to survive long periods of drought, plants grow around oases where water is available etc.)