Previous Test Questions for Final Exam
1. Outline the basic components of an ecosystem. [4] (2011 N2 4a)
2. Describe how the Gaia concept might be applied to pollution. [4] (2011 N2 2a)
3. Outline the Gaia hypothesis and suggest how it differs from more traditional ideas about how the
Earth works. [4] (2012 M2 4a)
see above answer to outline the Gaia hypothesis
more traditional ideas about how the Earth works may include things like:
the Earth is always changing and does not self-regulate
our actions will only harm us, not the whole planet
the Earth is too big for our actions to have an effect
the Earth is ours to do with what we choose
the Earth does not self regulate
4. Explain whether a small lake should be an open, closed, or isolated system. [2] (2012 M1 2b)
Open:
Exchanges Matter
precipitiation, runoff, fertilizer, oil/gas, animal waste as inputs
runoff/streams, evaporation, animals drinking, food leaving as outputs
Exchanges Energy
Sunlight, heat in
Heat, chemical energy in food out
(a) Distinguish between negative feedback and positive feedback. [2] (2010 M1 1b)
5. Construct a diagram to show how a positive feedback process involving methane may affect the
rate of global warming. [2]
6. Explain, with the aid of a diagram, what is meant by the term negative feedback. Refer to two
examples of negative feedback in your answer. [5] (2012 M2 4b)
negative feedback is the return to equilibrium of a system
(diagram could be a graph or chart)
Examples:
Lynx-Hare population
Increased body exercise produces sweat
Increased CO2 production increases photosynthesis
Warming might lead to more clouds, which reflect light back into space
7. Distinguish between transfer processes and transformation processes. [2] (2010 M1 3c)
8. State two transfer processes and two transformation processes in farming systems. [2] (2012 M1
5d)
Transfer:
water from irrigation or precipitation into plants
water vapor leaving plants into the atmosphere
fertilizer/nutrients from soil into plants
chemical energy taken from plants to humans
Transformation:
Sunlight into chemical energy
Chemical energy into kinetic energy
Liquid water to water vapor
Nutrients converted into chemical energy/biomass
9. List two inputs that are necessary to achieve high cereal yields. [2] (2011 N1 3b)
10. Annotate the diagram below with two inputs of water and two outputs of water in the
marshland ecosystem. [2] (2012 M2 1c)
Inputs:
Runoff
Precipitation
Streams/rivers into the marsh
Condensation
Outputs:
Evaporation
Streams/rivers out
Animals drinking
Uptake and evaporation by plants
11. State two reasons why computer models cannot predict exactly how global surface
temperatures will change during the 21st century. [2] (2010 M1 1c)
12. Identify two abiotic factors to which Mangrove trees are adapted. [1] (2011 N2 1a)
13. For an ecosystem you have studied, draw a food chain with at least four named species. [1]
(2011 M1 3b)
14. Explain the flow of energy through food webs. [5] (2011 N2 4b)
15. Explain why the pyramid of numbers in Figure 4(a) has fewer producers than consumers. [1]
(2011 M1 3a)
16. State one other type of pyramid used to show trophic levels [1] (2011 M1 3c)
17. Evaluate pyramids of numbers as a way of representing the biotic components of an ecosystem.
[2] (2011 M1 3d)
18. Describe two ways in which the pyramid structure of an ecosystem may be changed by a
named human activity. [2] (2011 M1 3e)
19. Rachel Carson’s book Silent Spring drew attention to the environmental impact of DDT on top
carnivores. Explain the vulnerability of top carnivores to non-biodegradable toxins, such as DDT,
entering food chains. [2] (2011 N1 2c(iv))
20. Define the term species. [1] (2012 M1 3b)
A group of organisms that interbreed and produce fertile offspring
21. With reference to the organisms in the resource booklet only (see diagram below), describe an
example of each of the following types of population interaction. [2] (2010 N2 1a)
22. The single-celled organism plasmodium spends part of its life cycle living in mosquitoes and
another part of its life living in humans where it causes the disease malaria. State the name of the
type of interaction between Plasmodium and its human host. [1] (2011 N1 2a)
23. Describe a method for measuring changes in abiotic components of a named ecosystem affected
by human activity. [5] (2010 M2 4a)
24. Using the key, identify the prey species A to F from the lower jaw bones found in owl pellets,
from a European woodland. [3] (2010 M1 2a)
25. The organisms below were found in an aquatic ecosystem. (2012 M1 3d)
(i) Suggest two visible characteristics of the organisms shown above which could be used to
construct an identification key. [1]
Number of legs, antennae, exoskeleton, body parts
(ii) Identify one limitation of using a key to identify an organism. [1]
Can be misleading/confusing, some species have high variability
juveniles of some species can be very different
26. To estimate the population of small mammals in a woodland, ecologists set traps in the area
before sunset and the following morning marked all captured animals before releasing them again.
(2010 M1 2b)
(i) State what information ecologists should record before releasing them again. [1]
(ii) A week later the traps are set again as before. State what data must be recorded when
the traps are opened and explain how these data may be used to estimate populations in the
area. [2]
27. State one method that could have been used to estimate tiger population [1] (2012 M1 1b, 1c)
Lincoln Index, capture, mark, release, recapture
should include a description of how to capture and mark the tigers.
28. With reference to the resource booklet, state two biomes which represent the plains bison’s
natural habitat. [1] (2010 N2 1a)
29. Describe the distribution, structure, and relative productivity of a named biome, and suggest
how it may be affected by global warming. [6] (2010 N2 3a)
a. The Island of Borneo lies on the equator, state two types of ecosystems that may be found on
Borneo. [1] (2010 M2 1a)
b. Explain why gross primary productivity is high in Borneo. [1] (2010 M2 1b)
30. Figure 6 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
light travels through the atmosphere. [1] (2010 M1 4a)
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. [2] (2010 M1 4b)
31. Figure 5 below shows the flow of energy through a freshwater ecosystem in Florida, USA. The
figures are given in kJ m-2 yr-1
a. Define the term Net Primary Productivity (NPP). [1] (2011 M1 4a)
b. Define the term Gross Secondary Productivity (GSP) [1] (2011 M1 4b)
c. Calculate the efficiency of conversion of total insolation (sunlight) to NPP in Figure 5. [1]
(2011 M1 4c)
d. List four possible reasons why not all sunlight emitted by the sun is used by plants for
photosynthesis. [2] (2011 M1 4d)
e. Explain, giving two reasons, why the net productivity of secondary consumers is much
smaller than primary consumers. [2] (2011 M1 4e)
f. Compare the energy efficiency of terrestrial and aquatic food production systems. [2]
(2011 M1 4f)
32. Define the term Gross Primary Productivity. [1] (2010 N1 4c)
33. For humans malaria can be a density-dependent limiting factor. Outline the concept of densitydependent limiting factors. [2] (2011 N1 2b)
34. Draw and label a survivorship curve for both a named K-strategist and r-strategist. [4] (2010 N2
5a)
35. Explain how K-strategies and r-strategies are linked to succession. [6] (2010 N2 5b)
36. Identify one natural factor and one human factor, which interrupt the process of succession. [2]
(2010 N2 1a (ii))
37. Explain the relationship between succession and equilibrium. [6] (2011 N2 5b)