Name: ___________________________________________ Date: ________________________
IGCSE BIO 10 2nd Semester S.Y. 2023-2024
General Instructions:
Read each question carefully and answer completely.
Do not use correction fluid.
The total mark for this paper is 35.
I. Multiple Choice (20 points)
Encircle the letter of the BEST answer.
1. Which type of energy is passed from organism to organism in a food chain?
A. light
B. chemical
C. heat
D. kinetic
2. Which row describes how energy flows through a biological system?
3. The diagram shows a food chain.
grass → mouse → owl
Which terms describe the position of the owl in this food chain?
4. The action of which type of bacteria would cause soil to be lacking in nitrates?
A. aerobic
B. denitrifying
C. nitrifying
D. nitrogen fixing
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5. What is defined as ‘all of the populations of different species in an ecosystem’?
A. community
B. environment
C. habitat
D. trophic level
6. The graph shows the change in population of an organism over time in an ecosystem.
Which row correctly identifies each phase of the population graph?
7. The diagram shows a food chain in a rock pool.
seaweed → whelks → crabs → seagulls
What will happen if the number of secondary consumers increases?
There will be ___.
A. fewer crabs
B. fewer seagulls
C. fewer whelks
D. less seaweed
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8. The diagram shows a food chain.
phytoplankton → zooplankton → herring → sea lion
Which diagram shows a pyramid of energy for this food chain?
9. In the nitrogen cycle, what are processes 1 and 2?
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10. The diagram shows a food web.
How many organisms feed at more than one trophic level?
A. 0 B. 1 C. 2 D. 3
11. The diagram shows energy transfer through a food chain. The labelled arrows represent
the energy transfers.
Which energy transfers are shown by the labelled arrows?
A. X is heat energy transfer and Z is chemical energy transfer.
B. Y is chemical energy transfer and X is light energy transfer.
C. X is chemical energy transfer and Y is heat energy transfer.
D. Z is heat energy transfer and W is light energy transfer.
12. The food web shows the feeding relationships in a woodland.
If all the chaffinches in the food web die, which effect would this have?
A. The amount of damage to trees will increase.
B. The food supply for grey squirrels will increase.
C. The number of wood pigeons will increase.
D. The population of caterpillars will decrease.
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13. The organisms in a food chain can be represented by pyramids of numbers or pyramids
of biomass.
Which diagram represents a pyramid of numbers?
14. A herd of red deer live in a forest that contains snakes and a large variety of birds.
Which group of organisms is an example of a population?
A. all the animals in the forest
B. all the red deer in the forest
C. all the organisms in the forest
D. all the plants in the forest
15. The diagram shows two pyramids based on food chains in which the producer
is a large tree.
What do the two pyramids represent?
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16. The diagram contains information about the number and mass of organisms in a food web.
What is the total biomass of all the primary consumers in this food web?
A. 130 kg B. 420 kg C. 3650 kg D. 130 000 kg
17. The diagram shows some of the stages in the nitrogen cycle.
Which arrow represents the process of nitrogen fixation?
18. Which term is used to describe the phase of fastest growth in a population of bacteria?
A. stationary
B. lag
C. exponential
D. sigmoid
19. Bacteria are active in the nitrogen cycle.
Which process in the nitrogen cycle is carried out by nitrifying bacteria?
A. the conversion of nitrogen gas to ammonia
B. the conversion of nitrogen gas to nitrates
C. the conversion of ammonia to nitrates
D. the conversion of nitrates to nitrogen
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20. The diagram shows a population growth curve.
How long does the population remain in the stationary phase?
A. 8 days
B. 12 days
C. 23 days
D. 48 days
II. Constructed Response (15 points)
Respond with comprehensive sentences that clearly address the question
by using relevant keywords to convey a thorough understanding of the topic.
1. Nitrogen is an important element for organisms.
In a livestock farm, waste from animals contains protein. This waste is often spread on
farmland as a fertilizer.
Describe how the nitrogen in protein is recycled in the soil into a form that plants can
absorb and use.
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2. Urea can be used as a fertilizer as it is a source of nitrogen.
Explain the importance of nitrate ions to plants.
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..........................................................................................................................................[1]
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3. The figure below is a part of a food web in a rainforest.
a. Complete the table using the information from the figure shown above.
The first one has been done for you.
[3]
b. Sometimes anacondas are able to kill and eat jaguars.
Using the information shown in the food web, state the name of the highest possible
trophic level of an anaconda that eats a jaguar.
…………………………………………………………………………………….………… [1]
c. Explain why the population of anacondas is always smaller than the population
of fruit bats in the food web shown in the figure.
Use the concept of energy flow in your answer.
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………………………………………………………………………………………………[3]
4. Coral reefs are important ecosystems.
Complete the sentence about ecosystems.
An ecosystem can be defined as a unit containing the ................................................. of
organisms and their ................................................., interacting together. [2]
Total Score: ____
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