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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

What is predation?

Please select an answer first.

Correct answer: A

The correct answer is An interaction in which one organism hunts, kills, and eats another.

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Predation transfers energy to the predator and can affect the size and behavior of both populations.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Predation transfers energy to the predator and can affect the size and behavior of both populations.

2. QuestionMultiple choice

What is mutualism?

Please select an answer first.

Correct answer: B

The correct answer is A relationship in which both species benefit.

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Mutualism benefits both partners, such as pollinators receiving nectar while helping plants reproduce.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Mutualism benefits both partners, such as pollinators receiving nectar while helping plants reproduce.

3. QuestionMultiple choice

What is parasitism?

Please select an answer first.

Correct answer: C

The correct answer is A relationship in which one organism benefits while the host is harmed.

  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 parasite obtains resources from a host and usually harms it without immediately killing 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 parasite obtains resources from a host and usually harms it without immediately killing it.

4. QuestionMultiple choice

What is commensalism?

Please select an answer first.

Correct answer: D

The correct answer is A relationship in which one species benefits and the other is not significantly affected.

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Commensalism benefits one species while the other experiences little or no measurable effect.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Commensalism benefits one species while the other experiences little or no measurable effect.

5. QuestionMultiple choice

What is competition?

Please select an answer first.

Correct answer: A

The correct answer is An interaction in which organisms use the same limited resource.

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Competition occurs when organisms need the same limited food, water, space, light, or mates.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Competition occurs when organisms need the same limited food, water, space, light, or mates.

6. QuestionMultiple choice

What can happen when two species have very similar niches?

Please select an answer first.

Correct answer: B

The correct answer is They may compete strongly for overlapping resources..

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Greater niche overlap generally increases competition because the species use similar resources.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Greater niche overlap generally increases competition because the species use similar resources.

7. QuestionMultiple choice

How can a predator-prey relationship affect population sizes?

Please select an answer first.

Correct answer: C

The correct answer is Predator and prey populations can rise and fall in response to each other..

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: More prey can support more predators, while more predators can reduce prey numbers, producing linked changes.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

More prey can support more predators, while more predators can reduce prey numbers, producing linked changes.

8. QuestionMultiple choice

How can competition change a population?

Please select an answer first.

Correct answer: D

The correct answer is Individuals that use resources differently may have an advantage when resources are 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: Competition can favor traits or behaviors that help individuals obtain scarce resources and reproduce.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Competition can favor traits or behaviors that help individuals obtain scarce resources and reproduce.

9. QuestionMultiple choice

Why can a keystone species have a large effect on its ecosystem?

Please select an answer first.

Correct answer: A

The correct answer is Its interactions help maintain community structure even when its population is not very large..

  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 keystone species can cause strong changes because many community relationships depend on it.
  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 keystone species can cause strong changes because many community relationships depend on it.

10. QuestionMultiple choice

What is an ecological disturbance?

Please select an answer first.

Correct answer: B

The correct answer is An event that changes the conditions or community structure of an ecosystem.

  1. Identify the ecosystem idea: Determine whether the question focuses on organisms, resources, energy, population size, interactions, or matter cycling.
  2. Connect the evidence: Fire, floods, storms, droughts, disease, and human activities can disturb ecosystems and alter populations.
  3. Predict the system effect: Use the relationship among organisms and their environment to select the outcome that best fits the ecosystem model.

Fire, floods, storms, droughts, disease, and human activities can disturb ecosystems and alter populations.

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