1.
The diagram below shows a simplified food web.
What is the role of the snake in this food web?
A.
Primary consumer
B.
Secondary consumer
C.
Tertiary consumer
D.
Producer
(Total 1 mark)
2.
What are the units of a pyramid of energy?
A.
kJ m–2 yr–1
B.
kJ m–1 yr–1
C.
J m–3 s–1
D.
J m2 s–1
(Total 1 mark)
IB Questionbank Biology
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3.
This question is about the food web below.
[Source: http://cbc.amnh.org/crisis/foodweb.html. Center for Biodiversity and Conservation, American Museum of
Natural History]
What will happen to the sizes of the populations in the food web above if the sea otter disappears?
A.
Large fish increase and sea urchins decrease.
B.
Abalones increase and sharks increase.
C.
Sea urchins increase and kelps decrease.
D.
Sea stars decrease and sharks increase.
(Total 1 mark)
IB Questionbank Biology
2
4.
This question is about the food web below
What is the energy transfer level from the kangaroo rat to the weasel shown in the food web
above?
A.
Three times greater than the energy transfer from the roadrunner to the bobcat
B.
Half the energy transfer from chaparral plants to the meadow mouse
C.
A quarter of the energy transfer from the quail to the bobcat
D.
Approximately the same as the energy transfer from the meadow mouse to the opossum
(Total 1 mark)
IB Questionbank Biology
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5.
The following diagram shows part of a food web from Yellowstone Park.
What would be the short-term effects on the populations of the other species if the gray wolf were
exterminated?
Beaver
Moose
Elk
Aspen
A.
Increase
Decrease
Increase
Increase
B.
Decrease
Decrease
Decrease
Decrease
C.
Increase
Increase
Decrease
Increase
D.
Decrease
Increase
Increase
Decrease
(Total 1 mark)
6.
Why do food chains in an ecosystem rarely contain more than five organisms?
A.
Nutrients are recycled by the decomposers back to the producers.
B.
Nutrients are lost from the ecosystem when organisms die.
C.
The conversion of food into growth by an organism is not very efficient.
D.
Energy is recycled by the decomposers back to the producers.
(Total 1 mark)
IB Questionbank Biology
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7.
The scarlet cup fungus (Sarcoscypha coccinea) obtains its nutrition from decaying wood by
releasing digestive enzymes into the wood and absorbing the digested products.
Which of the following terms describe(s) the fungus?
I.
Autotroph
II.
Heterotroph
III.
Saprotroph
A.
III only
B.
II and III only
C.
I and III only
D.
I, II and III
(Total 1 mark)
8.
(a)
Define the terms fundamental niche and realized niche.
Fundamental niche: .....................................................................................................
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Realized niche: .............................................................................................................
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(2)
(b)
Explain why the carnivores in an ecosystem tend to be fewer in number and have a smaller
biomass than the herbivores in the same ecosystem.
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(2)
IB Questionbank Biology
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(c)
Explain why carnivores tend to be more affected by biomagnification than organisms lower
down the food chain.
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(3)
(Total 7 marks)
9.
(a)
Label the levels of the trophic pyramid of energy shown below.
(3)
IB Questionbank Biology
6
(b)
Discuss the impact of alien species on the environment.
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(3)
(Total 6 marks)
10.
(a)
Define biomass.
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(1)
(b)
Describe how biomass may be measured.
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(2)
(c)
Explain the biomass change in different trophic levels.
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IB Questionbank Biology
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(3)
(Total 6 marks)
11.
Limpets are small animals that feed on the green algae which grow on rocks on seashores.
Oystercatchers (Haematopus bachmani) are birds that feed on limpets.
In a study on the north-west coast of the USA, where three limpet species are common (Lottia
digitalis, Lottia pelta and Lottia strigatella), the limpets were protected from the oystercatchers
by large wire cages. After two years the number of limpets in this area was compared with the
number of limpets in an area without cages, where oystercatchers were present.
[Source: Wooton, J T. 1992. “Indirect effects, prey susceptibility, and habitat selection: impacts of birds on limpets and
algae”. Ecology. Vol 73. Pp 981–991. Copyright by the Ecological Society of America.]
(a)
State the effect that the exclusion of the oystercatchers had on the total number of limpets
per m2.
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IB Questionbank Biology
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(1)
(b)
Construct a food web to show the feeding relationship between the three species of limpets,
the oystercatchers and the green algae.
(2)
(c)
Suggest reasons for the difference in numbers of L. strigatella between the areas where
oystercatchers were present and where oystercatchers were excluded.
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(3)
IB Questionbank Biology
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There is evidence to show that both air and water temperatures have increased over a period of
time. An investigation was undertaken to determine the effect this change in climate had on the
populations of another species of limpet, Patella depressa, around south-west England.
The population of the limpet was recorded in many locations and around 30 years later, this study
was repeated. The chart below compares the population in each of the locations.
[Source: Burrows, M T et al. 2009. “Predicting the effects of marine climate change on the invertebrate prey of the birds
of rocky shores: Predicting effects of climate change on invertebrates”. IBIS (Special Edition). Vol 145. Pp 40–47.]
(d)
On the map above label one location,
(i)
with the letter X, where the limpet population was abundant in the 1950s and
occasional in the 1980s (1980–1984).
(1)
(ii)
with the letter Y, where the limpet population was abundant in both the 1950s and in
the 1980s (1980–1984).
(1)
(e)
Outline, using the data, the overall trend in the limpet population from the 1950s to the
1980s (1980–1984).
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(2)
IB Questionbank Biology
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(f)
Suggest two reasons for the change in limpet population between the 1950s and the 1980s
(1980–1984).
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(2)
(Total 12 marks)
12.
(a)
Outline one example of herbivory.
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(2)
(b)
State the units used in a pyramid of energy.
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(1)
(c)
Explain the small biomass of organisms in higher trophic levels.
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(2)
(Total 5 marks)
IB Questionbank Biology
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13.
Up to two additional marks are available for the construction of your answers.
(2)
(a)
Living organisms at every trophic level are part of the carbon cycle. Draw a labelled
diagram of the carbon cycle to show the processes involved.
(9)
(b)
Explain, using an example of a food chain, how trophic levels can be deduced.
(4)
(c)
Explain methods that can be used to measure the rate of photosynthesis.
(5)
(Total 20 marks)
14.
Up to two additional marks are available for the construction of your answers.
(2)
(a)
Describe what is meant by a food chain using an example with four named organisms.
(4)
(b)
Outline how global warming may affect arctic ecosystems.
(5)
(c)
Explain how natural selection can lead to evolution using antibiotic resistance in bacteria as
an example.
(9)
(Total 20 marks)
15.
Up to two additional marks are available for the construction of your answers.
(2)
(a)
Describe the movement of energy and nutrients in an ecosystem.
(6)
(b)
Explain how sexual reproduction can eventually lead to evolution in offspring.
(8)
(c)
Using simple external recognition features, distinguish between the plant phyla bryophyta
and angiospermophyta.
(4)
(Total 20 marks)
IB Questionbank Biology
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