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Ecosystem Dynamics Practice Tests

These Grade 7 Science practice tests build understanding of ecosystem components, energy flow, food chains, food webs, population interactions, carrying capacity, matter cycles, disturbances, and conservation.

Skills covered

  • Distinguishing biotic and abiotic factors, habitats, niches, populations, communities, and ecosystems
  • Tracing energy through producers, consumers, decomposers, food chains, and food webs
  • Explaining predation, competition, mutualism, parasitism, commensalism, and keystone species
  • Connecting limiting factors and carrying capacity to population change
  • Applying carbon, nitrogen, and water cycle ideas to ecosystem and conservation scenarios

How to use these practice tests

For each question, identify the organisms and environmental conditions involved. Then trace the direction of energy, matter, or population change before choosing the best-supported outcome.

For more Grade 7 Science practice, return to the Grade 7 Science category.

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Grade 7 Ecosystem Dynamics Practice Tests

Practice Grade 7 Science ecosystem dynamics questions about energy flow, food webs, interactions, populations, cycles, and conservation.

Choose the best answer for each question. Review the explanation after submitting your answers.

10 Questions
0/10 Questions0 %
Correct 0
Incorrect 0
Unanswered 10
1. QuestionMultiple choice

A lake receives extra fertilizer runoff and develops a thick algal bloom. What may happen next?

Please select an answer first.

Correct answer: A

The correct answer is Decomposition can use oxygen, creating low-oxygen conditions for aquatic animals..

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Excess nutrients can cause algal growth; when algae die, decomposers consume oxygen as they break them down.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Excess nutrients can cause algal growth; when algae die, decomposers consume oxygen as they break them down.

2. QuestionMultiple choice

A rabbit population grows rapidly after predators are removed. Why might it later decline?

Please select an answer first.

Correct answer: B

The correct answer is Food and space may become limiting as the population approaches carrying capacity..

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Rapid growth can use resources faster than they are replaced, increasing competition, disease, and starvation.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Rapid growth can use resources faster than they are replaced, increasing competition, disease, and starvation.

3. QuestionMultiple choice

If wolves are removed from a forest food web, which result is possible?

Please select an answer first.

Correct answer: C

The correct answer is Deer may increase and consume more vegetation, affecting other organisms..

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Removing a predator can release prey from predation pressure and create a cascade through food and habitat relationships.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Removing a predator can release prey from predation pressure and create a cascade through food and habitat relationships.

4. QuestionMultiple choice

Why might planting native plants help restore an ecosystem?

Please select an answer first.

Correct answer: D

The correct answer is Native plants can provide local food and shelter while supporting established relationships..

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Native plants are adapted to local conditions and can support native consumers, decomposers, and pollinators.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Native plants are adapted to local conditions and can support native consumers, decomposers, and pollinators.

5. QuestionMultiple choice

A nonnative predator enters an island ecosystem with prey that lack defenses. What is a likely concern?

Please select an answer first.

Correct answer: A

The correct answer is The predator could reduce native prey populations and disrupt food-web relationships..

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: A new predator can create a strong selection pressure and alter populations that did not evolve with it.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

A new predator can create a strong selection pressure and alter populations that did not evolve with it.

6. QuestionMultiple choice

A farmer creates a wildlife corridor between two forest patches. What ecosystem effect can it support?

Please select an answer first.

Correct answer: B

The correct answer is It can allow organisms to move, find resources, and maintain gene flow between populations..

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Corridors connect fragmented habitats and can support movement, reproduction, and genetic exchange.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Corridors connect fragmented habitats and can support movement, reproduction, and genetic exchange.

7. QuestionMultiple choice

Why can protecting wetlands benefit people and ecosystems?

Please select an answer first.

Correct answer: C

The correct answer is Wetlands can provide habitat, filter water, store floodwater, and support diverse food webs..

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Wetlands perform ecosystem services while supporting producers, consumers, decomposers, and migratory species.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Wetlands perform ecosystem services while supporting producers, consumers, decomposers, and migratory species.

8. QuestionMultiple choice

Which action best supports sustainable use of a fish population?

Please select an answer first.

Correct answer: D

The correct answer is Harvesting fish at a rate that allows the population to replace itself.

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Sustainable harvest stays within the population's ability to reproduce and the ecosystem's carrying capacity.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Sustainable harvest stays within the population's ability to reproduce and the ecosystem's carrying capacity.

9. QuestionMultiple choice

A drought lowers water levels in a pond. Which observation would show an ecosystem response?

Please select an answer first.

Correct answer: A

The correct answer is Aquatic populations decline or change as habitat and available oxygen become more limited..

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Water availability is an abiotic factor that can change habitat, resources, and survival for pond organisms.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Water availability is an abiotic factor that can change habitat, resources, and survival for pond organisms.

10. QuestionMultiple choice

Which evidence would best show that a conservation plan is working?

Please select an answer first.

Correct answer: B

The correct answer is Target populations and habitat conditions improve over several monitoring periods..

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Repeated monitoring provides evidence about population trends, habitat quality, and whether management goals are being met.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Repeated monitoring provides evidence about population trends, habitat quality, and whether management goals are being met.

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