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Ecology and Environment — Free MYP2 Sciences Practice Questions
1QuestionDefinition and Components of an EcosystemConcept Practice
2 marks~3 minCriterion A
The diagram below shows a pond ecosystem containing a fish, a plant, a rock, and water.
a
Identify one biotic component (a living thing) from the diagram. [1]
b
Identify one abiotic component (a non-living thing) from the diagram. [1]
Solutions
2QuestionEfficiency of Energy TransferConcept Practice
2 marks~3 minCriterion A
The diagram shows a food chain with the following energy values:
Grass (1000 J) → Rabbit (100 J) → Fox (10 J)
Grass (1000 J) → Rabbit (100 J) → Fox (10 J)
a
Identify the term used to describe the percentage of energy passed from one feeding level (trophic level) to the next. [1]
b
Using the values above, calculate the percentage of energy transferred from the rabbit to the fox. [1]
Solutions
3QuestionEnergy Loss at Each Trophic LevelConcept Practice
2 marks~3 minCriterion B
The diagram shows energy values at each trophic level (feeding level) in a food chain:
Grass: 10,000 kJ → Grasshopper: 1,000 kJ → Frog: 100 kJ → Snake: 10 kJ
Grass: 10,000 kJ → Grasshopper: 1,000 kJ → Frog: 100 kJ → Snake: 10 kJ
a
Identify the pattern in energy values as you move from grass to snake. [1]
b
Explain why energy decreases at each trophic level. [1]
Solutions
4QuestionAir Water and Soil PollutionConcept Practice
2 marks~3 minCriterion A
The diagram shows a river with three pollution sources labelled X, Y, and Z.
- Label X: a factory pipe releasing waste into the river
- Label Y: smoke from a car exhaust
- Label Z: a pile of garbage on the riverbank
- Label X: a factory pipe releasing waste into the river
- Label Y: smoke from a car exhaust
- Label Z: a pile of garbage on the riverbank
a
Identify the type of pollution (water, air, or soil) represented by each label X, Y, and Z. [1]
b
Explain why Label Z represents a different type of pollution from Label X. [1]
Solutions
5QuestionDefinition and Importance of BiodiversityConcept Practice
2 marks~3 minCriterion A
A diagram of a forest ecosystem shows three labelled components:
| A | species richness |
|---|---|
| B | genetic diversity |
| C | ecosystem diversity |
a
Identify which label matches the definition: "the variety of different species living in an area." [1]
b
Explain why having many different species in an area is important for the survival of that ecosystem. [1]
Solutions
6QuestionDefinition of Habitat and ExamplesConcept Practice
5 marks~8 minCriterion B
The bar graph below shows the number of plant species found in three habitats with different rainfall levels.
Forest (1500 mm): 45 species
Grassland (800 mm): 28 species
Desert (250 mm): 12 species
Forest (1500 mm): 45 species
Grassland (800 mm): 28 species
Desert (250 mm): 12 species
a
Identify the habitat with the greatest number of plant species. [1]
b
Describe the relationship between rainfall and the number of plant species shown in the graph. [2]
c
A habitat is a place that provides food, water, and shelter. Compare the forest and the desert as habitats for plants, using data from the graph to support your answer. [2]
Solutions
7QuestionAdaptations for Survival in Extreme EnvironmentsConcept Practice
3 marks~5 minCriterion A
The table below shows the average fur thickness of two fox species measured in winter.
| Region A (−30 °C) | Arctic fox 5.2 cm | red fox 2.8 cm |
|---|---|---|
| Region B (−10 °C) | Arctic fox 3.9 cm | red fox 2.1 cm |
a
Identify which species has thicker fur in both regions. [1]
b
Explain why thicker fur helps a fox survive in a cold environment. [1]
c
Compare the fur thickness of the two species and explain what this suggests about the environments each species has adapted to. [1]
Solutions
8QuestionConstructing and Interpreting Food ChainsConcept Practice
2 marks~3 minCriterion A
In the food chain below, grass is a producer — an organism that makes its own food.
grass → rabbit → fox
grass → rabbit → fox
a
Identify the trophic level of the rabbit. [1]
b
Explain why the rabbit occupies that trophic level. [1]
Solutions
9QuestionDefinition and Components of an EcosystemAssessment Practice
3 marks~5 minCriterion B
The diagram shows a pond food chain: algae → water fleas → small fish → herons.
a
Identify the role of small fish in relation to water fleas. [1]
b
Describe what happens to the water flea population when all small fish are removed from the pond. [1]
c
Explain how removing small fish could also affect the algae population. [1]
Solutions
10QuestionDefinition and Components of an EcosystemAssessment Practice
6 marks~9 minCriterion C
A student seals water, one small plant, and three snails in a glass jar. She rates water clarity on a scale of 1 (very cloudy) to 10 (perfectly clear) each day for 10 days.
| Day | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
|---|---|---|---|---|---|---|---|---|---|---|
| Water clarity | 10 | 9 | 8 | 7 | 7 | 6 | 6 | 5 | 5 | 5 |
a
Identify the overall trend in water clarity over the 10 days. [1]
b
Explain how the snails and the plant together could cause this trend. [2]
c
A second student claims the plant alone — not the snails — is causing the water to become cloudy. Compare what you would expect to see in a jar with only a plant versus a jar with only three snails, and explain which result would support the original hypothesis that snails cause the cloudiness. [3]
Solutions
11QuestionDefinition and Components of an EcosystemAssessment Practice
6 marks~9 minCriterion D
Fertilizer runoff from nearby farms has caused excessive algae growth in a local pond, reducing the dissolved oxygen available for fish. One proposed solution is to plant buffer zones — strips of native plants along the pond's edge that absorb fertilizer before it enters the water.
a
Identify one component of the pond ecosystem that is directly affected by the fertilizer runoff. [1]
b
Explain how a buffer zone of native plants reduces the impact of fertilizer runoff on the pond. [2]
c
Compare two limitations of using buffer zones as a solution to the runoff problem. [3]
Solutions
12QuestionEnergy Loss at Each Trophic LevelAssessment Practice
6 marks~9 minCriterion D
A school wants to reduce its environmental impact by changing its lunch menu. Grass contains kJ of energy. Using the 10% energy transfer rule (only 10% of energy passes from one feeding level to the next):
a
Calculate the energy available to a student who eats a beef burger from a cow fed on that grass. [1]
b
The school considers replacing beef burgers with plant-based burgers made directly from the same grass. Calculate the energy available to the student from the plant-based burger, and compare this with your answer to part (a). [2]
c
Explain one benefit of eating food lower on the food chain for feeding a growing human population, and identify one limitation of using only the energy argument to make food choices. [3]
Solutions
13QuestionLimitations of Pyramids in Real EcosystemsAssessment Practice
3 marks~5 minCriterion C
A woodland ecosystem has one large oak tree, many insects living on it, and a few birds that eat the insects.
a
Identify which trophic level (feeding level) makes the woodland pyramid of numbers appear inverted. [1]
b
Explain why counting individual organisms, rather than their size, causes this inverted shape. [1]
c
Compare the pyramid of numbers with a pyramid of biomass (total living material) for this woodland ecosystem, and state which gives a more accurate picture of energy distribution. [1]
Solutions
14QuestionAir Water and Soil PollutionAssessment Practice
7 marks~11 minCriterion D
A factory near a river releases wastewater containing oil and heavy metals (toxic substances that harm living things). Its filter removes 90% of the oil but only 30% of the heavy metals before the water enters the river.
a
Identify two harmful effects that would occur in the river without any filtering. [2]
b
Explain why the remaining heavy metals in the river water are still a serious problem, even after filtering. [3]
c
Compare the environmental and economic impacts of allowing the factory to continue operating with this filter. [2]
Solutions
15QuestionNatural vs Human-Induced Environmental ChangeAssessment Practice
6 marks~9 minCriterion B
A student measured the mass of leaf litter (dead leaves) decomposing (breaking down) over 8 weeks in two settings.
Measurements taken at weeks: 0, 2, 4, 6, 8.
| Compost bin (human-managed) — mass (g) | 100 | 85 | 72 | 61 | 52 |
|---|---|---|---|---|---|
| Forest floor (natural) — mass (g) | 100 | 92 | 85 | 79 | 74 |
Measurements taken at weeks: 0, 2, 4, 6, 8.
a
Identify the pattern of mass loss in each setting. [2]
b
Estimate the mass of leaf litter in each setting at week 10. Show your working. [2]
c
Compare the rate of decomposition in the two settings and give one scientific reason for the difference. [2]
Solutions
16QuestionGlobal Warming and Climate ChangeAssessment Practice
3 marks~5 minCriterion C
The graph below shows atmospheric CO₂ concentration (in parts per million, ppm) and global average temperature (in °C) from 1900 to 2020.
a
Identify the trend shown by both variables between 1900 and 2020. [1]
b
Explain how increasing CO₂ concentration causes global temperatures to rise. [1]
c
A student says: "Temperature rises caused the CO₂ increase, not the other way around." Using the greenhouse effect, explain why scientists disagree with this claim. [1]
Solutions
17QuestionDefinition and Importance of BiodiversityAssessment Practice
6 marks~9 minCriterion B
A biologist recorded the number of plant species in four forest patches on a small island.
| Patch size () | 1 | 5 | 10 | 20 |
|---|---|---|---|---|
| Number of plant species | 4 | 9 | 13 | 18 |
a
Describe the relationship between patch size and number of plant species. Use data in your answer. [2]
b
Estimate the number of plant species expected in a 30 patch. Show your reasoning. [2]
c
A biologist claims this pattern would look the same on every island. Describe one piece of evidence from the data that supports this claim and one reason why it might not apply to a different island. [2]
Solutions
18QuestionDefinition and Importance of BiodiversityAssessment Practice
4 marks~6 minCriterion D
Your school is considering replacing a grassy area — home to various plants and small animals — with a concrete sports court.
a
Identify two benefits that the biodiversity (variety of living things) in the grassy area provides to students. [2]
b
Explain one limitation of using these benefits as the main reason to keep the grassy area instead of building the sports court. [2]
Solutions
19QuestionDefinition and Importance of BiodiversityAssessment Practice
5 marks~8 minCriterion C
The bar graph shows species count and the line graph shows plant biomass fluctuation (the change in total plant matter) during a drought year for four habitats.
| Species richness (number of species) | Forest 45 | Grassland 30 | Wetland 50 | Urban Park 15 |
|---|---|---|---|---|
| Biomass fluctuation | Forest 5% | Grassland 12% | Wetland 3% | Urban Park 20% |
a
Identify the habitat with the lowest biomass fluctuation during the drought. [1]
b
Explain why a habitat with more species is better able to maintain stable biomass during a drought. [2]
c
Compare the species richness and biomass fluctuation of the Wetland and the Urban Park, and use both values to explain which habitat was more resilient (able to recover from stress) to drought. [2]
Solutions
20QuestionStructural and Behavioral AdaptationsAssessment Practice
5 marks~8 minCriterion C
The bar graph below shows the survival rates of three animal species in a desert and a forest habitat.
Species A has thick waxy skin (a structural adaptation — a physical body feature).
Species B is nocturnal (a behavioural adaptation — an activity pattern).
Species C has no adaptation.
Species A has thick waxy skin (a structural adaptation — a physical body feature).
Species B is nocturnal (a behavioural adaptation — an activity pattern).
Species C has no adaptation.
a
Identify the species with the highest survival rate in the desert. [1]
b
Explain why Species A survives better than Species B in the desert. [2]
c
Compare the effectiveness of structural and behavioural adaptations across both habitats, using data from the graph. [2]
Solutions
21QuestionAdaptations for Survival in Extreme EnvironmentsAssessment Practice
6 marks~9 minCriterion D
A conservation team builds heated shelters to help desert tortoises survive cold nights. Unlike natural burrows, the shelters do not control humidity (the amount of water vapour in the air), causing some tortoises to become dehydrated.
a
Identify one way a natural burrow helps a desert tortoise keep water in its body. [1]
b
Explain why the heated shelter causes tortoises to lose more water than a natural burrow does. [2]
c
Compare the heated shelter with a natural burrow, and suggest one design change that would improve the tortoise's chances of survival. [3]
Solutions
22QuestionConstructing and Interpreting Food ChainsAssessment Practice
5 marks~8 minCriterion D
A student models a local pond using this food chain:
algae → tadpole → dragonfly nymph → fish
A pollutant then destroys all the algae in the pond.
algae → tadpole → dragonfly nymph → fish
A pollutant then destroys all the algae in the pond.
a
State what happens to the fish population in the short term. [1]
b
Explain how the loss of algae affects the tadpoles and dragonfly nymphs. [2]
c
Identify one limitation of this food chain model and explain why it makes the model less reliable for predicting what really happens in the pond. [2]
Solutions
23QuestionTrophic Levels and Energy Transfer IntroductoryAssessment Practice
8 marks~12 minCriterion B
Students measured the energy (in kJ) available at each trophic level — the feeding position of an organism in a food chain — for three food chains.
Food chain 1: Grass (20 000 kJ) → Rabbit (2 000 kJ) → Fox (200 kJ)
Food chain 2: Algae (15 000 kJ) → Insect (1 500 kJ) → Fish (150 kJ) → Heron (15 kJ)
Food chain 3: Oak tree (50 000 kJ) → Caterpillar (5 000 kJ) → Bird (500 kJ) → Hawk (50 kJ)
Food chain 1: Grass (20 000 kJ) → Rabbit (2 000 kJ) → Fox (200 kJ)
Food chain 2: Algae (15 000 kJ) → Insect (1 500 kJ) → Fish (150 kJ) → Heron (15 kJ)
Food chain 3: Oak tree (50 000 kJ) → Caterpillar (5 000 kJ) → Bird (500 kJ) → Hawk (50 kJ)
a
Identify the percentage of energy transferred between each pair of trophic levels in food chains 1, 2, and 3. [2]
b
Calculate the missing energy values for the food chain below. Show your working.
Grass (25 000 kJ) → Grasshopper (? kJ) → Frog (? kJ) → Snake (? kJ) [3]
Grass (25 000 kJ) → Grasshopper (? kJ) → Frog (? kJ) → Snake (? kJ) [3]
c
Compare the energy available at the producer level with the energy available at the top predator level across all four food chains. Use this to explain why food chains rarely have more than four or five trophic levels. [3]
Solutions
24QuestionEnergy Flow Through Food WebsAssessment Practice
5 marks~8 minCriterion C
In a grassland food web, grass (the producer) contains 50 000 kJ of energy. Rabbits (primary consumers) obtain 5 000 kJ, foxes (secondary consumers) obtain 500 kJ, and hawks (tertiary consumers) obtain 50 kJ.
a
Calculate the percentage of energy transferred from grass to rabbits. Show your working. [1]
b
Calculate the percentage of energy transferred from rabbits to foxes. Show your working. [1]
c
A student claims that energy transfer becomes less efficient at each higher trophic level. Using your results from (a) and (b), and calculating the transfer from foxes to hawks, compare the efficiency of all three transfers and explain whether the student's claim is correct. [3]
Solutions