This document appears to be an exam for a grade 11 environmental systems and societies class. It contains multiple choice and short answer questions about various topics related to ecosystems, including: - Processes that reduce sunlight reaching Earth's surface - Calculating the proportion of global net primary productivity used for human food consumption - Reasons for food shortages in some societies - Comparing biomass, net primary productivity, and soil fertility across forest ecosystems - Defining ecosystem terms and providing examples - Calculating net primary productivity per kg of biomass for different ecosystems - Comparing annual production and respiration data across ecosystems The exam contains questions assessing understanding of key environmental concepts as well as data analysis and interpretation skills

1. Guru Charan Kumar/IB ESS
HUMANITIES DEPARTMENT
ENVIRONMENTAL SYSTEM & SOCITIES
GRADE 11 SUMMATIVE- FEBURARY 2013
1 HOUR
TOTAL MARKS-45
1. Figure below shows the estimated size of some global energy flows for one year.
(a) State two processes that reduce the amount of sunlight reaching the Earth’s surface,
as the light travels through the atmosphere.
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(b) Using the data in Figure 6, calculate, as a percentage range, the proportion of global NPP used
for human food consumption in one year.
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(c) Suggest two reasons why food is in short supply in some societies.
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2. Guru Charan Kumar/IB ESS
2. The data figure 1 shows some characteristics of three different forest ecosystems.
Figure 1.
Vegetation
Tropical rainforest
Litter
thin humus layer
Temperate
deciduous woodland
Temperate
coniferous woodland
Litter (pine needles)
deep humus (acidic) layer
Brown colour becoming
lighter with depth
Pale grey layer with
considerable leaching
Some leaching
Red colour with high iron
and aluminium content
Soil profile coarse texture
Litter
deep humus layer
Darker layer with iron and
humus enrichment
Parent material
Parent material weathered Parent material
to great depth
Mean biomass /
tons hectare –1
1000
800
600
400
200
0
[Source: adapted from Goodman and Hughes, Geography A level Q and A, Letts Educational, 1995, page 19]
(a)
(i)
Define what is meant by the term biomass.
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(1)
(ii)
Outline a method by which biomass can be measured.
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3. Guru Charan Kumar/IB ESS
(2)
(b)
(i)
Identify which of the three forest ecosystems contains the most biomass.
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(1)
(ii)
Explain why this ecosystem is so productive. (In your answer you should include
factors other than those in figure 1.)
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(3)
(iii)
Explain the difference between biomass and net primary productivity (NPP).
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(2)
(c)
(i)
Of the three soil types shown in figure 1, state which forest’s soil is most fertile.
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(1)
(ii)
Explain how you arrived at your answer to (c) (i).
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(3)
(Total 13 marks)
3) (a) Outline the term ecosystem.
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(1)
(b)
State an example of a flow within a named ecosystem.
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(1)
(c)
State one example of biological storage within a forest ecosystem.
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(1)
(d)
Calculate the net primary productivity per kg of biomass for the boreal forest ecosystem in
the table below.
Comparison of ecosystem productivity
Mean net primary
productivity /
kg m–2 yr–1
Mean biomass /
kg m–2
Net primary
productivity per kg
biomass per year
Temperate forest
1.20
32.5
0.037
Boreal forest
0.80
20.0
Tropical rainforest
2.20
45.0
0.049
Savanna grassland
0.90
4.0
0.225
Ecosystem
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5. Guru Charan Kumar/IB ESS
Tundra
0.14
0.6
0.233
[Source: “Table of ecosystem productivity”, Geography Review, Volume 5, Number 1 (1991).
Reproduced by permission of Philip Allan Updates]
(1)
(e)
Compare and explain the data for two of the ecosystems in the table above.
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(4)
(f)
Briefly outline a method for measuring biomass of a primary producer.
Name of primary producer: .........................................................................................
Method: .......................................................................................................................
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6. Guru Charan Kumar/IB ESS
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(3)
(Total 11 marks)
4. The table below shows annual production and respiration in kcalm−2 year−1 in five
ecosystems.
Net Community Productivity (NCP) = Net Primary Productivity (NPP) + Secondary
Productivity (SP)
Ecosystems:
A = Alfalfa grass field; B = young pine plantation
C = medium aged oak-pine forest; D = large river; E = mature tropical rainforest
[Adapted from Odum, E. P. (1975) Fundamentals in Ecology, Saunders & Co.]
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(a) (i) Define the term ecological efficiency. [1]
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(ii) Identify the ecosystem above which is likely to have the greatest species diversity.
Give a reason for your answer.
[1]
Ecosystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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(b) State three abiotic factors that affect primary productivity in the ecosystems above.
[1]
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(c) For ecosystem A
(i) Calculate the net primary productivity (NPP) and fill in the table.
(ii) Calculate the efficiency of conversion of GPP to NCP. Show your working.
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(iii) Explain why ecosystem A has the highest NCP.
[1]
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(iv) Explain why ecosystem E has the highest GPP but zero NCP.
[1]
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(d) State and explain the impact that:
(i) a significant increase in the use of chlorofluorocarbons (CFCs) might have on the GPP
of these ecosystems.
[2]
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(ii) Continuous acid deposition might have on the NPP in ecosystem B.
[2]
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(iii) A 25 % decrease in the area of ecosystem E might have on global temperatures.
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[2]