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Ecology and Environment — Free MYP3 Sciences Practice Questions
1QuestionDefinition and Components of an EcosystemConcept Practice
3 marks~5 minCriterion C
The bar graph below shows the energy available at each trophic level in a grassland ecosystem.
Trophic level — Energy available (kJ): Producers — 10 000, Primary consumers — 1 000, Secondary consumers — 100, Tertiary consumers — 10.
Trophic level — Energy available (kJ): Producers — 10 000, Primary consumers — 1 000, Secondary consumers — 100, Tertiary consumers — 10.
a
Describe the trend in energy from producers to tertiary consumers. [1]
b
Explain why energy decreases between trophic levels. [1]
c
A student claims that a tertiary consumer receives 1% of the energy originally available at the producer level. Using the data, evaluate whether this claim is correct. [1]
Solutions
2QuestionDefinition and Components of an EcosystemConcept Practice
2 marks~3 minCriterion A
The diagram below shows components found in a pond ecosystem.
Pond components: Fish · Water · Rocks · Lily pads (plants) · Sunlight · Air (oxygen) · Bacteria
(a) Identify the biotic components and the abiotic components from the list above. Write each component under the correct heading. [2]
Biotic components: ___, ___, ___
Abiotic components: ___, ___, ___, ___
Pond components: Fish · Water · Rocks · Lily pads (plants) · Sunlight · Air (oxygen) · Bacteria
(a) Identify the biotic components and the abiotic components from the list above. Write each component under the correct heading. [2]
Biotic components: ___, ___, ___
Abiotic components: ___, ___, ___, ___
Solutions
3QuestionEfficiency of Energy TransferConcept Practice
2 marks~3 minCriterion B
The diagram shows a food chain with the following energy values:
Grass: 10 000 J
Rabbit: 1 000 J
Fox: 100 J
Describe the pattern of energy change as energy moves through this food chain, and explain what happens to the energy that is not transferred to the next trophic level. [2]
Grass: 10 000 J
Rabbit: 1 000 J
Fox: 100 J
Describe the pattern of energy change as energy moves through this food chain, and explain what happens to the energy that is not transferred to the next trophic level. [2]
Solutions
4QuestionEfficiency of Energy TransferConcept Practice
3 marks~5 minCriterion A
A grassland food chain transfers energy as follows:
Grass (producer): 10 000 kJ
Rabbit (primary consumer): 1 000 kJ
Fox (secondary consumer): 100 kJ
Grass (producer): 10 000 kJ
Rabbit (primary consumer): 1 000 kJ
Fox (secondary consumer): 100 kJ
a
Calculate the percentage of energy transferred from grass to rabbit. Show your working. [1]
b
Calculate the percentage of energy transferred from rabbit to fox. Show your working. [1]
c
Explain why energy decreases at each trophic level in this food chain. [1]
Solutions
5QuestionAir Water and Soil PollutionConcept Practice
2 marks~3 minCriterion A
The diagram shows a river with four labeled pollution sources: A (a factory with a discharge pipe leading directly into the river), B (a farm with fertiliser runoff), C (a sewage treatment outlet), and D (a residential area with stormwater drains).
a
Identify which labeled source is most likely to release chemical pollution from industrial waste. [1]
b
Explain why that source produces chemical pollution rather than other types of pollution. [1]
Solutions
6QuestionMethods of ConservationConcept Practice
2 marks~3 minCriterion B
A conservation team investigates how the number of native shrubs planted affects bird species diversity. They plant 50 shrubs in Plot A, 100 shrubs in Plot B, and 150 shrubs in Plot C. After one year, they count the number of bird species in each plot. Rainfall is kept the same across all plots.
a
Identify the independent variable and the dependent variable in this investigation. [1]
b
Explain why keeping rainfall the same across all plots is important in this investigation. [1]
Solutions
7QuestionDefinition and Importance of BiodiversityConcept Practice
2 marks~3 minCriterion A
The food web below shows four organisms: grass, rabbit, fox, and hawk.
a
Identify the producer in this food web. [1]
b
Explain why the rabbit is classified as a primary consumer in this food web. [1]
Solutions
8QuestionAdaptations for Survival in Extreme EnvironmentsConcept Practice
2 marks~3 minCriterion A
The diagram below shows a polar bear with four labeled parts:
A: large ears
B: thick white fur
C: sharp claws
D: small tail
A: large ears
B: thick white fur
C: sharp claws
D: small tail
a
Identify the labeled part that is an adaptation for maintaining warmth in the Arctic. Write the letter only. [1]
b
Explain how this adaptation helps the polar bear survive in the Arctic environment. [1]
Solutions
9QuestionConstructing and Interpreting Food ChainsConcept Practice
2 marks~3 minCriterion A
The food chain below shows the flow of energy between organisms.
Grass → Rabbit → [ ? ] → Fox
Grass → Rabbit → [ ? ] → Fox
a
Identify one organism that could fill the blank box. [1]
b
State the role of that organism in the food chain. [1]
Solutions
10QuestionDefinition and Components of an EcosystemAssessment Practice
6 marks~9 minCriterion B
An ecologist recorded the number of organisms in four ecosystems.
| Forest | producers 5000 | primary consumers 800 |
|---|---|---|
| Grassland | producers 3000 | primary consumers 600 |
| Pond | producers 2000 | primary consumers 400 |
| Desert | producers 500 | primary consumers 100 |
a
Calculate the ratio of producers to primary consumers for each ecosystem. Describe the pattern you see. [2]
b
A fifth ecosystem has 4000 producers. Apply the pattern from part (a) to predict the number of primary consumers. Show your working. [2]
c
Ecosystem D (Desert) supports far fewer organisms at every level than Ecosystem A (Forest). Using the concept of energy flow between trophic levels, explain why the number of producers is always greater than the number of consumers in any ecosystem. [2]
Solutions
11QuestionDefinition and Components of an EcosystemAssessment Practice
6 marks~9 minCriterion D
A student investigates a local pond ecosystem. Fertilizer runoff from a nearby farm has caused excessive algae growth, covering the water surface and blocking sunlight from reaching deeper parts of the pond.
a
Identify one biotic component and one abiotic component of this pond ecosystem that are directly affected by the algae bloom. Give a specific example of each. [2]
b
Explain how the algae bloom disrupts the pond's food web. [2]
c
A farmer proposes completely removing all algae from the pond. Analyse whether this is an effective long-term solution to the problem. [2]
Solutions
12QuestionEfficiency of Energy TransferAssessment Practice
3 marks~5 minCriterion C
The diagram below shows a food chain with energy values at each trophic level.
Grass (10 000 kJ) → Rabbit (1 000 kJ) → Fox (100 kJ)
Grass (10 000 kJ) → Rabbit (1 000 kJ) → Fox (100 kJ)
a
State the term for the percentage of energy transferred from one trophic level to the next. [1]
b
Calculate the percentage of energy transferred from grass to rabbit. Show all working. [1]
c
A student claims that the fox is a more efficient predator than the rabbit because it is faster. Using the data above, explain whether this claim is correct. [1]
Solutions
13QuestionEfficiency of Energy TransferAssessment Practice
2 marks~3 minCriterion D
When animals such as cattle eat crops, only about of the energy from those crops is transferred to the animal's body. The remaining is lost through movement, body heat, and waste.
Explain why eating crops such as rice or beans directly is more sustainable than eating meat from animals raised on those crops. In your answer, refer to energy transfer efficiency. [2]
Explain why eating crops such as rice or beans directly is more sustainable than eating meat from animals raised on those crops. In your answer, refer to energy transfer efficiency. [2]
Solutions
14QuestionPollution Effects on Food Chains and WebsAssessment Practice
6 marks~9 minCriterion B
| Trophic Level | DDT Concentration (ppm) |
|---|---|
| Phytoplankton | 0.04 |
| Zooplankton | 0.5 |
| Small fish | 2.0 |
| Osprey | 25.0 |
a
Calculate the biomagnification factor between each consecutive trophic level. [2]
b
Explain how the pattern in your results from (a) shows that DDT concentration is related to trophic level. [2]
c
Analyse the data to explain why the osprey is at greatest risk from DDT compared with organisms at lower trophic levels. [2]
Solutions
15QuestionAir Water and Soil PollutionAssessment Practice
6 marks~9 minCriterion D
A small farming town has found that nitrates from agricultural fertilizers have contaminated its groundwater drinking supply. The town council is considering building a constructed wetland — a shallow area where water flows slowly through soil and plant roots — to filter nitrates before they reach the drinking supply.
a
Describe two ways in which a constructed wetland removes nitrates from water. Use relevant nitrogen cycle terminology in your answer. [2]
b
Explain one advantage of using a constructed wetland rather than a chemical treatment plant to remove nitrates. [2]
c
The town receives heavy snowfall for four months each year, and farmland surrounds the town on all sides. Analyse one limitation of building a constructed wetland in this town, and explain how this limitation affects the practicality of the solution. [2]
Solutions
16QuestionGlobal Warming and Climate ChangeAssessment Practice
3 marks~5 minCriterion C
The graph below shows atmospheric CO2 concentration (ppm) and global average temperature anomaly (°C) from 1850 to 2020.
a
Describe the relationship between CO2 concentration and global temperature anomaly shown in the graph. [1]
b
Explain how increased CO2 concentration causes global temperatures to rise. [1]
c
A student claims: "The graph proves that CO2 causes temperature rise." Do you agree? Justify your answer using evidence from the graph and your scientific knowledge. [1]
Solutions
17QuestionMethods of ConservationAssessment Practice
5 marks~8 minCriterion C
A scientist claims that reforestation increases soil carbon by 15\% per year. To investigate this, soil carbon (g/kg) was measured in two forest plots over 5 years.
Plot A (reforestation) — Year 0: 20, Year 1: 23, Year 2: 26, Year 3: 30, Year 4: 35, Year 5: 40
Plot B (natural regeneration) — Year 0: 20, Year 1: 21, Year 2: 22, Year 3: 23, Year 4: 24, Year 5: 25
Plot A (reforestation) — Year 0: 20, Year 1: 23, Year 2: 26, Year 3: 30, Year 4: 35, Year 5: 40
Plot B (natural regeneration) — Year 0: 20, Year 1: 21, Year 2: 22, Year 3: 23, Year 4: 24, Year 5: 25
a
Calculate the total percentage increase in soil carbon for Plot A over the 5-year period. [2]
b
Calculate the mean annual percentage increase in soil carbon for Plot A. [1]
c
Compare the mean annual percentage increase for Plot A with the scientist's claim. Justify whether the data supports the claim. [2]
Solutions
18QuestionDefinition and Importance of BiodiversityAssessment Practice
4 marks~6 minCriterion D
A local council is considering converting a small urban wetland into a sports field. The wetland currently provides several ecosystem services because of its biodiversity.
a
Describe two ecosystem services that the wetland's biodiversity provides to the local community. [2]
b
Explain one reason why depending on biodiversity to deliver these ecosystem services may be unreliable. [2]
Solutions
19QuestionAdaptations for Survival in Extreme EnvironmentsAssessment Practice
4 marks~6 minCriterion D
Conservationists in a hot desert place metal shade structures — metal sheets on wooden poles, 1 m above the ground — to help fennec foxes survive extreme heat. Fennec foxes naturally use underground burrows that stay cool and humid.
a
Describe one way in which the metal sheets may make the shaded area warmer than a natural burrow. [1]
b
Explain why the artificial structures are unlikely to provide the humidity conditions that fennec foxes need to survive. [2]
c
Identify one assumption the engineers made about the foxes' needs, and analyse how this assumption could reduce the effectiveness of the artificial structures as a conservation tool. [1]
Solutions
20QuestionStructural and Behavioral AdaptationsAssessment Practice
5 marks~8 minCriterion C
A model bird pecks at paper moths placed against a green background. In each of 5 trials, the bird pecks for 30 seconds. The bird is trained to remain still before each trial. Results are recorded below.
| Trial 1 | brown captured: 8 | green captured: 3 |
|---|---|---|
| Trial 2 | brown captured: 7 | green captured: 4 |
| Trial 3 | brown captured: 9 | green captured: 2 |
| Trial 4 | brown captured: 6 | green captured: 5 |
| Trial 5 | brown captured: 10 | green captured: 1 |
a
Calculate the mean number of brown moths and the mean number of green moths captured per trial. [2]
b
Explain why the green moths survived better than the brown moths in this experiment. [1]
c
A student claims: "Remaining still is more important than body color for survival, because the bird captured more brown moths in every trial." Analyse whether the experimental data supports this claim. [2]
Solutions
21QuestionStructural and Behavioral AdaptationsAssessment Practice
4 marks~6 minCriterion B
The data below shows fur thickness and average habitat temperature for four Arctic mammals.
| Mammal | Polar bear | Arctic fox | Musk ox | Caribou |
|---|---|---|---|---|
| Fur thickness (cm) | 10 | 6 | 8 | 4 |
| Average habitat temperature (°C) | −30 | −25 | −20 | −15 |
a
Describe the relationship between fur thickness and average habitat temperature using data from the table. [2]
b
The Arctic hare lives in areas with an average temperature of −28°C. Predict its fur thickness and explain your reasoning using the pattern you described. [2]
Solutions
22QuestionConstructing and Interpreting Food ChainsAssessment Practice
5 marks~8 minCriterion B
A grassland ecosystem has the following biomass at each trophic level:
Producers: 5000 kg
Primary consumers: 500 kg
Secondary consumers: 50 kg
Tertiary consumers: 5 kg
Producers: 5000 kg
Primary consumers: 500 kg
Secondary consumers: 50 kg
Tertiary consumers: 5 kg
a
Calculate the percentage of biomass transferred from producers to primary consumers. [1]
b
Calculate the percentage of biomass transferred at each of the remaining two trophic level transitions. [2]
c
Using all three of your calculated values, analyse what they suggest about the pattern of energy transfer between trophic levels in ecosystems. [2]
Solutions
23QuestionConstructing and Interpreting Food ChainsAssessment Practice
8 marks~12 minCriterion D
A government plans to build a large dam that will flood a forest ecosystem. The food web contains:
Secondary consumers: bears (eat deer and insects), fish (eat insects and algae)
| Producers | trees | stream algae |
|---|---|---|
| Primary consumers | deer (eat trees) | insects (eat tree leaves) |
Secondary consumers: bears (eat deer and insects), fish (eat insects and algae)
a
Construct one food chain from this web and explain why flooding would most severely disrupt it. [2]
b
Explain how removing bears from the food web would affect the populations of deer, insects, and trees. Use examples from the web in your answer. [3]
c
The dam will generate electricity for 200 000 homes and irrigate 50 000 hectares of farmland, but will permanently destroy the forest ecosystem. Analyse whether these economic benefits justify the ecological damage. In your answer, identify one limitation of predicting the long-term effects on the ecosystem. [3]
Solutions
24QuestionConstructing and Interpreting Food ChainsAssessment Practice
6 marks~9 minCriterion C
A farmer sprays insecticide on a wheat crop to eliminate aphids. After a few weeks, the bird population near the field falls sharply. A neighbour suggests that a simple food chain is not enough to understand what is happening in the ecosystem.
a
Apply your knowledge of energy flow to construct the food chain for wheat, aphids, and birds. Use arrows to show the direction of energy flow. [2]
b
Explain one consequence of the decline in the bird population for the local ecosystem. [2]
c
The neighbour says a food web would be more useful than a food chain for predicting the effects of the insecticide. Analyse one reason why a simple food chain is limited for this purpose. [2]
Solutions