O-LevelGeographyThe natural environment2217/12 · Oct/Nov 2018 · Q425 Marks

Study Fig. 4.1, which shows lines joining together places of equal rainfall (isohyets) in Namibia. [Figure 4.1] Study Fig. 4.2, which shows a food web in an area of low rainfall. [Figure 4.2]

(a)(i)A desert is defined as an area with less than 250 mm of rainfall. On Fig. 4.1 shade the area of less than 250 mm of rainfall in Namibia.[1]
(a)(ii)Describe two other characteristics of a hot desert climate.[2]
(a)(iii)Explain why there is a large area of hot desert in Namibia by referring to the following factors shown in Fig. 4.1: latitude the prevailing winds the ocean current.[3]
(a)(iv)Explain why a hot desert may form near mountains (in a rain shadow).[4]
(b)(i)Using Fig. 4.2, describe three different ways in which the natural vegetation, soil and wildlife are dependent on each other.[3]
(b)(ii)Describe the characteristics of vegetation which make it able to survive in areas where rainfall is low.[5]
(c)For a named area of tropical rainforest you have studied, describe and explain the characteristics of the vegetation. Name of area of tropical rainforest ..........................................................[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 2018). The mark or mark type is shown in brackets.

[1] Shading on map Note: Must shade all of relevant area, can shade parts lying in Angola
[2] High temperatures; Note: Hot=0 Seasonal differences; Large daily/diurnal temperature range/low temperatures at night/valid statistics for day and night temperatures; Low humidity; 2 @ 1 mark
[3] Latitude: It is close to the Tropic of Capricorn; Rays of sun concentrated/high angle of/overhead sun; High pressure/sinking/descending air; Prevailing winds: Blow from across the land; Dry winds/the winds lose moisture before they reach the desert; Ocean Current: Cold current; Cold temperatures make it less likely that the air will hold moisture/rain falls at sea/air mass is dry when it reaches land; 3 @ 1 mark
[4] Ideas such as: The air mass rises (on windward side) of mountain range; Air expands; Air mass cools; Condensation of water vapour; Saturation of air mass; Precipitation on mountains; Air descends; Heating of air mass at leeward side; No condensation takes place/no moisture in air/dry air; 4 1 mark
[3] Ideas such as: The vegetation needs the soil to grow/nutrients in the soil are used by the vegetation; Animals/insects/primary producers(or example) eat/get energy from/energy flows from plants; Animals/predators eat/get energy from/energy flows from animals/insects (or examples); Nutrients returned to soil from rotting vegetation/decaying fauna/animals excretion; 3 1 mark
[5] Characteristics such as: Deep/long/tap roots; Wide/shallow roots; Fleshy/think/large stems/trunk; Thorns/spikes/small leaves/prickles/leathery leaves/waxy leaves; Tough/leathery/waxy/thick/ridged bark/skin; Few stomata/pores; Hairy/waxy cuticle; Low level vegetation/short; Light colour/white/light green; Ephemeral/remains dormant during drought/only flowers when rain falls/sheds leaves if dry; Wide distance apart; 5 1 mark or development
[7] Levels marking Level 1 (1-3 marks) Statements which describe or explain the characteristics of tropical rainforest vegetation. Level 2 (4-6 marks) Uses named example. More developed statements which describe and explain the characteristics of tropical rainforest vegetation. E.g. Tall and so compete for light = L2 Buttress roots for stability = L2 (Note: Max 5 if no named or inappropriate example) Level 3 (7 marks) Uses named example. Comprehensive and accurate statements which describe and explain, including place specific information. Content Guide: Answers are likely to refer to: Layers Lianas Epiphytes Parasitic vegetation Buttress roots Undergrowth Place specific reference is likely to consist of: Named places, Named species, etc.