Download 1. The table below gives the percentage of world energy supplied

1.
The table below gives the percentage of world energy supplied from various sources, in 1900
and in 1998.
Source of Energy
1900
1998
94
30
Oil
4
41
Natural gas
1.5
26
Hydro-electric and nuclear sources
0.5
3
Coal
(a)
Explain the significance of the data in the table for the environment.
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(3)
(b)
Discuss two advantages and two disadvantages of one of the sources of energy named in
the table. (Hydro-electric and nuclear power may be considered separately.)
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(4)
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(c)
Name and evaluate one sustainable source of energy not listed above.
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(3)
(d)
It has been calculated that the ecological footprint of the population of Singapore is 264
times greater than the area of Singapore. Explain what this means.
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(3)
(e)
Assume that in a large city with a stable population, the proportion of the population that
has a vegetarian diet increases. Explain how this change might affect the city’s ecological
footprint.
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(2)
(Total 15 marks)
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2.
The diagram below shows a cross-section through a typical rock pool. A variety of species are
shown that belong to the rock pool community, together with some organisms that inhabit other
parts of the rocky or sandy shore.
oystercatcher
rock pool
channel wrack
(seaweed)
limpets
water
sea anemone
shore crab
periwinkle
green seaweed saw wrack
(seaweed)
shrimp
brittlestar hiding polychaete
worm in sand
under rock
barnacles
mollusc
starfish
[M J Reiss and J L Chapman, Ecology and Conservation, (1994).
Reproduced by permission of Cambridge University Press]
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For a named consumer organism shown in the diagram above, describe and evaluate a method
for measuring its gross and net secondary productivity.
Name of organism: ................................................................................................................
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(Total 5 marks)
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3.
A group of students sampled the animals in a local ecosystem. Their results are shown below.
The numbers of individuals captured from each species is indicated in brackets next to each
diagram.
P (6)
Q (1)
R (4)
T (2)
S (8)
U (2)
V (3)
W (1)
Organisms are not shown to scale
[Source: Lyneborg. L. (1973) Dune and Moorland Life, Blandford Press]
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(a)
Simpson’s diversity index is calculated using:
D=
N ( N  1)
n(n  1)
where N is the total number of organisms of all the species found and n is the number of
each species.
Calculate a value for D. Show your working.
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(2)
(b)
The students used a key to help with the identification of the organisms. Suggest two
different visible features that would be suitable for use in the key.
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(2)
The next day the students sampled a similar ecosystem at a site 2 km away. The Simpson’s
diversity index for the second ecosystem was found to be much lower.
(c)
(i)
State an abiotic factor that might affect the diversity of two similar ecosystems at
different sites.
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(1)
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(ii)
Explain why differences in the abiotic factor named in (i) might affect diversity
between two sites.
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(2)
(iii)
Describe how you would measure and compare the abiotic factor named in (i) at
each site.
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(3)
To estimate the population of animal S, the students marked the eight individuals that they
found and returned them to the ecosystem. One week later, the students caught 20 individuals of
animal S, of which five were marked.
(d)
(i)
State the name of this method of estimating a population.
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(1)
(ii)
Estimate the size of the population of animal S.
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(1)
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(iii)
Suggest one reason why the estimate might be unreliable.
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(1)
(iv)
Explain why brightly coloured paint should not be used to mark the animals.
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(1)
Animal R feeds on plants. The students kept six individuals of animal R for a month in the
laboratory to measure their productivity.
(e)
(i)
Explain why the mass of food given to the animals and the mass of feces produced
must be measured.
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(2)
(ii)
Explain why samples of the food and feces should be dried before weighing.
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(1)
(iii)
Outline how the energy absorbed by the animals from their food can be calculated
from the dry masses of food and feces.
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(2)
(iv)
Show how you would calculate net productivity from measurements of the masses
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of the animals at the beginning and end of the experiment.
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(1)
(Total 20 marks)
4.
The table below shows the global carbon transfers during one year.
Carbon inputs to atmosphere
/ 109 tonnes yr–1
Carbon removed from atmosphere
/ 109 tonnes yr–1
Burning fossil fuels
5.3
Increase in biomass of
existing plants
1.3
Deforestation
1.6
Absorption by oceans
2.0
Regrowth of forest after
deforestation
0.5
[E I Newman, Applied Ecology and Environmental Management, 2nd edition, (Oxford: Blackwell Science, 2000),
page 17. Reproduced by permission of Wiley-Blackwell]
(a)
Use the information in the table above to complete the flow diagram to show the flows
and storages of carbon in 109 tonnes yr–1.
5.3
FOSSIL FUELS
Burning
ATMOSPHERE
VEGETATION
(5)
(b)
Calculate the net increase in carbon levels in the atmosphere after one year.
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(1)
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(c)
(i)
State the process by which carbon is transferred from the atmosphere and
assimilated by plants.
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(1)
(ii)
For the process named in (c) (i), label the arrows in the following diagram to show
the inputs and outputs of energy and matter for the plant
(3)
(d)
(i)
Explain why the rate of increase in the amount of carbon in the atmosphere should
be controlled.
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(2)
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(ii)
Explain, using examples, how international cooperation can help to control levels
of atmospheric carbon.
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(3)
(Total 15 marks)
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5.
The data figure 1 shows some characteristics of three different forest ecosystems.
Figure 1.
Vegetation
Tropical rainforest
Litter
thin humus layer
Red colour with high iron
and aluminium content
Soil profile coarse texture
Temperate
deciduous woodland
Temperate
coniferous woodland
Litter
deep humus layer
Litter (pine needles)
deep humus (acidic) layer
Brown colour becoming
lighter with depth
Pale grey layer with
considerable leaching
Some leaching
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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(2)
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(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 then 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)
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(ii)
Explain how you arrived at your answer to (c) (i).
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(3)
(Total 13 marks)
The graph below shows net primary productivity (NPP) of eight major biomes.
Net primary productivity / g m–2 yr–1
6.
2500
2000
1500
1000
500
0
Tropical Deciduous Tropical Coniferous Agricultural Temperate
grasslands
rainforests
forests
grasslands
forests
land
Tundra
Deserts
Biomes
[D Waugh, Geography An Integrated Approach, (Nelson Thornes Ltd., 2000) p. 304.
Reproduced by permission of Nelson Thornes Ltd.]
(a)
(i)
Compare, and give reasons for, the differences in net primary productivity between
any two biomes named in the graph.
(4)
(ii)
State two of the main factors which influence productivity.
(2)
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(b)
Explain, with the aid of a diagram, the transfers and transformations of energy as it flows
through an ecosystem.
(7)
(c)
Compare the structure and distribution of tropical rainforests and tundra.
(4)
Expression of ideas (3)
(Total 20 marks)
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