Question 1

Which group could be a population?

  A  

all the animals and plants on an isolated island

  B  

all the birds counted in one day in a garden

  C  

all the bacteria in a colony of Bacillus subtilis

  D  

all the insects occupying three hectares of farmland

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Question 2

What is the ecological definition of the term community?

  A  

all the food webs in an ecosystem

  B  

all the individuals of one species in an area

  C  

all the organisms in an area


  D  

the living organisms and their non-living environment

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Question 3

A tree carries out photosynthesis and provides organic compounds for other organisms in a forest.

It takes carbon dioxide from the atmosphere and returns oxygen to the atmosphere. It takes water from the soil into its roots and its leaves lose water to the atmosphere. Many other organisms live in the tree.

Which term describes the tree?

  A  

population


  B  

community

  C  

ecosystem

  D  

trophic level

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Question 4

The first stage of primary succession is the pioneer community.

Which of the following statements about a pioneer community are correct?

1 - species produce large numbers of wind-carried seeds or spores

2 - biomass is low

3 - many species are lichens and mosses

  A  

1, 2, and 3

  B  

only 1 and 2

  C  

only 2 and 3

  D  

only 1

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Question 5

Barnacles are small animals that live on rocky shores. Adult barnacles are fixed to rocks and do not move about. They catch passing food in the water with modified limbs called cirri when the tide comes in.

Chthalamus stellatus is a species of barnacle found around UK shores.

Two students wished to estimate the population size of C. stellatus on a rocky shore near their school.

What could the students use for estimating the C. stellatus population?

   1 - an abundance scale, such as ACFOR

   2 - quadrat sampling

   3 - mark-release-recapture

  A  

1, 2, and 3

  B  

only 1 and 2

  C  

only 2 and 3

  D  

only 1

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Question 6

The nitrogen cycle involves a range of reactions and microorganisms.

Which process usually occurs under anaerobic conditions?

  A  

conversion of amino acids to ammonium compounds


  B  

conversion of urea to ammonium compounds

  C  

nitrification

  D  

nitrogen fixation

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Question 7

A farmer grows a different crop in a field each year for three years. In the fourth year the farmer plants a leguminous crop and then ploughs this into the soil. The next year the rotation starts again.

Which microorganisms will increase by the time the rotation starts again?

1 - denitrifying bacteria

2 - nitrifying bacteria

3 - nitrogen-fixing bacteria

4 - decomposing bacteria

  A  

1, 2, and 3

  B  

1, 2, and 4

  C  

1, 3, and 4

  D  

2, 3, and 4

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Question 8

Which soil would have the smallest number of denitrifying bacteria?

  A  

compressed agricultural soil


  B  

poorly drained forest soil

  C  

water-logged clay soil

  D  

well-aerated garden soil

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Question 9

Decomposition of organic matter can cause the concentration of ammonia to rise in a fish tank. High concentrations of ammonia in the tank are toxic to fish. Bacteria may be added to remove the ammonia.

Which type of bacteria should be added?

  A  

ammonifying

  B  

denitrifying

  C  

nitrifying

  D  

nitrogen-fixing

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Question 10

Which processes are essential in making nitrogen in dead plant material available to growing plants?

1 - ammonification

2 - deamination

3 - nitrification

4 - nitrogen fixation

  A  

1, 2, and 3 only

  B  

1, 2, and 4 only

  C  

1, 3, and 4 only

  D  

2, 3, and 4 only

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Question 11

Which bacteria convert ammonium compounds to nitrites?

  A  

Azotobacter

  B  

Nitrobacter

  C  

Nitrosomonas

  D  

Rhizobium

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Question 12

An insect consumes 180 J of plant material.

Of this, 95 J of energy is passed out in the insect’s faeces and 58 J is used for respiration.

Which percentage of the energy, in the original plant material taken in by the insect, is converted into biomass?

  A  

10%

  B  

15%

  C  

32%

  D  

47%

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Question 13

The diagram shows the flow of energy through a food chain. Figures are in kJ m-2 year-1.

What percentage of light energy is available to the herbivore?

  A  

0.12%

  B  

0.38%

  C  

0.50%

  D  

1.00%

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