O-LevelGeographyThe natural environment2217/12 · Oct/Nov 2010 · Q425 Marks

Study Fig. 7, a climate graph of an area of tropical desert in the Northern Hemisphere. Name the month with an average temperature of 21 °C and an average rainfall of 10mm.

(a)(i)Study Fig. 7, a climate graph of an area of tropical desert in the Northern Hemisphere. Name the month with an average temperature of 21 °C and an average rainfall of 10mm.[1]
(a)(ii)Use Fig. 7 to estimate: A the annual range of temperature, B the annual average rainfall.[2]
(a)(iii)Explain why average temperatures between May and September are high in the desert area shown in Fig. 7.[3]
(a)(iv)Explain why tropical deserts have a low annual rainfall. You may use labelled diagrams or sketch maps in your answer.[4]
(b)(i)Study Photographs A and B (Insert), which show vegetation in a tropical desert. Describe the differences in the vegetation shown in Photographs A and B.[3]
(b)(ii)What adaptations are used by vegetation, such as that shown in Photographs A and B, to survive in tropical desert areas?[5]
(c)For a named area of tropical desert you have studied, explain why and how it is at risk from human activities.[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 2010). The mark or mark type is shown in brackets.

[1] (a) (i) October
[2] (a) (ii) Range of temperature = 21°C/12–33°C Annual average precipitation = 95–105mm
[3] (a) (iii) Ideas such as: absence of cloud cover; overhead/high angle of sun; in northern hemisphere etc
[4] (a) (iv) Ideas such as: Long way from oceans; Not close to sea/large lake; trade winds; Blow over large areas of land hence no source of moisture; Rain shadow; High pressure/descending air; Cold currents etc
[3] (b) (i) Differences such as: A is tree/shrub/B is cactus; A has leaves/B spines; A has trunk/stem/ B has fleshy stem; A has higher/larger plants than B; Higher density of vegetation in A, etc
[5] (b) (ii) Ideas such as: Seeds/plants remain dormant during long dry spells; narrow/spiky leaves; to reduce rates of evapotranspiration (dev) to protect plant from animals (dev); long/tap roots; wide spreading roots; to reach underground water (dev); Some plants/cacti store water; in order to survive long periods of drought (dev); waxy/tough outer layer etc
[7] (c) Levels marking Level 1 (1–3 marks) Statements including limited detail explaining how or why the area is at risk from human activities. (e.g. the area is used for farming, resources/oil is mined/drilled in the area, animals are killed, tourists destroy dunes, overgrazing etc)
[7] (c) Levels marking Level 2 (4–6 marks) Uses named example More developed statements explaining how or why the area is at risk from human activities. (e.g. large herds of animals are grazed in the area which destroys vegetation, resources/oil is mined/drilled in the area and wildlife is killed as habitat is destroyed, the use of quad bikes/trampling on the dunes wears them away etc) (NB MAX 5 if no named example)
[7] (c) Levels marking Level 3 (7 marks) Uses named example (e.g. Arabian Desert). Comprehensive and accurate statements explaining how and why the area is at risk from human activities, including some place specific reference. [NB For place specific reference candidates could name specific parts of the desert or countries affected.]