O-LevelGeographyThe natural environment2217/22 · May/June 2011 · Q730 Marks

Some students, who lived in Rio de Janeiro in Brazil, wanted to do some fieldwork in a local forest. It was a tropical rainforest but some parts had been deforested for plantation farming and to use the timber for building houses. Many types of vegetation grow naturally in the forest.

(a)Use arrows to match the 'heads' and 'tails' in the table below to describe three ways that vegetation adapts to the climate in the tropical rain forest. An example has been completed for you. Heads Drip tips on leaves Shallow roots Large leaves Buttress roots Tails to extract soil nutrients to make the tree more stable to remove heavy rainfall to allow more transpiration[3]
(b)(i)Suggest why the students decided to record data at five sites in each area.[1]
(b)(ii)Suggest why a transect line was used to locate the five sites in each area.[2]
(c)(i)At each of the five sites along the transect the students measured the speed of infiltration. Fig. 11 (Insert) shows the equipment they used. Explain how they made their measurements.[3]
(c)(ii)The students placed a quadrat on the ground at each measuring site. A quadrat is shown in Photograph A (Insert). Using the quadrat they estimated the percentage of vegetation cover and the percentage of bare ground. They also recorded the number of types of vegetation in the area of the quadrat. The results of these measurements are shown in Table 2 (Insert). Which area contains the highest number of vegetation types? Circle your answer. A B C[1]
(c)(iii)The measurements taken at one site are shown below. Infiltration time = 25 seconds Number of vegetation types = 5 Percentage of vegetation cover = 80 Percentage of bare ground = 20 At which site and in which area were these measurements taken? Site ......................................... Area .........................................[1]
(c)(iv)Calculate the average infiltration time in area B. Show your calculation below. Answer: ..................................... seconds[2]
(d)(i)Use the information in Table 2 (Insert) to plot the following on Fig. 12. • the infiltration times for sites 4 and 5 at site A. • the number of types of vegetation found at site 3 in area B. • the percentage of vegetation cover and the percentage of bare ground at sites 3 and 4 in area C. [Figure 12][5]
(d)(ii)Use the information in Table 2 and Fig. 12 to reach a conclusion about Hypothesis 1: There are fewer types of vegetation where water infiltrates into the ground more quickly. Support your conclusion with evidence.[3]
(d)(iii)The students decided that Hypothesis 2: Where water infiltrates into the ground more quickly, vegetation cover is greater was correct. What evidence from Fig. 12 supports their conclusion?[3]
(d)(iv)Suggest why water infiltrates into the ground more quickly where vegetation cover is greater.[2]
(e)Suggest why infiltration times are different between the three areas A, B and C in Fig. 10. [Figure 10][4]

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 (May/June 2011). The mark or mark type is shown in brackets.

[3] Drip tips on leaves ..... to remove heavy rainfall (1 - 3rd row); Shallow roots ...... to extract soil nutrients (2 - 1st row); Large leaves ..... to allow more transpiration (3 – 4th row); NOTE that Buttress roots... to make the trees more stable has already been done;[3 @ 1 = 3]
[1] To give fair results / identify anomaly; To avoid bias / be objective; To have a wider range / variety / wider selection; NOT To reflect reality / Better results without qualification
[2] 5 sites along transect is systematic; Easier to select sites on a straight line; Easier to locate 5 sites at equal intervals on straight line; Consistent way of studying 3 areas and comparing them
[3] Tube / bottomless measuring cylinder pushed / knocked into ground; Measured amount / 1 litre of water poured into cylinder; Time or use stopwatch until water infiltrates / sinks / disappears / drains into ground; NOT: Dig hole in ground –must refer to cylinder going into ground.
[1] Area C
[1] Site 3 and Area C – need both for the mark.
[2] 25+35+21+48+52 OR 181 / 5 (1) = 36.2 (1); 1 mark for knowing how to calculate it; 1 mark for the correct answer as here.
[5] Two points plotted at 50 and 44 on Fig. 12 Area A (1) joined up by straight lines from 3-5 (1); Plot and shade bar correctly at 3 on Fig. 12 Area B (1); Two divided bar graphs completed at 80 / 20 and 57 / 43 on Fig. 12 Area C (1) and shaded correctly (1) NO MARKS IF PLOTTED WRONG WAY UP
[3] Hypothesis is false / disagree – (1). If say true / partially true then no marks at all.; Second mark if write new hypothesis e.g. “more types of vegetation where water infiltrates more quickly”. (1); Evidence can only be for comparative statement from Area C and / or Area A:; At C shortest infiltration time and most types of vegetation (1) 30 secs or less / 18 types (1); At A longest infiltration time and least types of vegetation (1) 36 secs or more / 11 types (1); Allow a Data mark max. 1 but not compulsory. NO CREDIT FOR DATA FROM INDIVIDUAL SITES.
[3] No hypothesis mark here. Reserve use of data for 2 marks max.; Shortest infiltration time in area C (all < 30secs / avg 24.6 / range 20 / 30 secs) where highest %age of vegetation cover (57–80% / avg 68.45%); OR; Longest infiltration time in area A (all > 36secs / 36-58 range) where lowest %age of vegetation cover (8–38% / 24.2% avg).; DO NOT DOUBLE CREDIT OPPOSITE STATEMENTS OR REFS TO GROUND COVER %AGES OR REFS TO DATA FROM INDIVIDUAL SITES
[2] Water infiltrates quickly where vegetation greater due to:; *soil being broken up by vegetation roots; *soil not compacted / loose / has gaps / cracks; *quicker absorption by vegetation so promotes more growth / roots absorb water; NOT Ground is hard without qualification
[4] One separate reason required for A B and C with 1 floating mark. Mark for consequence not for cause. 1 MAX if general consequences with no Area ref. No need to refer to effect on infiltration time.; Examples:; Area A is popular with tourists so compacted soil; vegetation eroded; Parking / roads / footpaths cause impermeable surfaces; compacted soil; Area B has been deforested so less ground cover; Dirt road may create less vegetation; compacted soil; Area B shows contrasts between sites with and without vegetation cover; In areas with little vegetation cover sun will harden the ground; Area C is natural forest with lots of vegetation types; no trampling of vegetation; less compacted soil