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WorksheetYear 7Level 2 · Standard

Free Year 7 Relationships in Ecosystems: Competition, Predation and Symbiosis Worksheet

Students learn the ways organisms interact in an ecosystem: competition for resources, predator–prey relationships and the three kinds of symbiosis (mutualism, commensalism and parasitism). They classify real examples, interpret a rabbit and fox population data set to explain the predator–prey cycle, and predict the effects of removing a species.

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Year
Year 7
Subject
Science
Topic
Ecosystems & Food Chains
Difficulty
Level 2 · Standard
Estimated time
35 minutes
Curriculum
Australian Curriculum
Questions
14
Answers
Included, with working
Format
PDF (A4), print or complete online

Students will practise

  • describing competition between and within species
  • classifying symbiotic relationships as mutualism, commensalism or parasitism
  • interpreting predator–prey population data
  • explaining the predator–prey cycle
  • predicting the effects of changes to populations

Curriculum: Australian Curriculum. We show specific outcome codes only where they have been verified against the official curriculum document.

What's next?

Completed: Relationships in Ecosystems: Competition, Predation and Symbiosis

  1. 1Classification and Dichotomous Keys
  2. 2Using a Microscope: Parts, Magnification and Slide Preparation
  3. 3Plant and Animal Cells: Structures and Functions

How to use this worksheet

  1. Print the PDF or complete it on screen. Write the student's name and date at the top.
  2. Read the instructions for each part together before starting. Encourage working to be shown.
  3. Mark with the answer sheet. Use the model answers and success criteria as a guide rather than a single right answer.
  4. Record the score, celebrate what went well, then follow the "What's next" suggestion.

Common questions

Who is this worksheet for?

Year 7 students (typically ages 12–13) working on ecosystems & food chains. It is pitched at level 2 · standard.

Are the answers included?

Yes. The PDF includes a full answer sheet with model answers and success criteria where there is more than one good answer. You can also view the answers online.

How long does it take?

About 35 minutes for 14 questions. Short, regular sessions work best: two or three a week beats one long one.

Do I need to sign up to download?

No. Click Download Free PDF and it opens immediately. It is free for personal, classroom and homeschool use.

What should we do next?

Try Classification and Dichotomous Keys.

Preview

Success TutoringWorksheetsYear 7 · Science · Ecosystems & Food Chains

Relationships in Ecosystems: Competition, Predation and Symbiosis

Name

Date

Score /

Ask: who benefits, who is harmed, and who is unaffected?

Part A: Living together

Read the passage, then circle the type of relationship.

Organisms in an ecosystem constantly interact. In predation, a predator hunts and eats its prey. In competition, organisms struggle for the same limited resources, such as food, water, light, space or partners to breed with.

Symbiosis is a close, long-term relationship between two different species. In mutualism both species benefit. In commensalism one benefits and the other is unaffected. In parasitism the parasite benefits and the host is harmed.

1.Bees collect nectar from flowers and carry pollen between them. Both benefit. This is …
  1. Amutualism
  2. Bcommensalism
  3. Cparasitism
2.A tick feeds on the blood of a dog and can spread disease to it. This is …
  1. Amutualism
  2. Bcommensalism
  3. Cparasitism
3.Barnacles attach to the skin of a whale and get carried to new feeding areas. The whale is not affected. This is …
  1. Amutualism
  2. Bcommensalism
  3. Cparasitism
4.A clownfish lives among the stinging tentacles of a sea anemone, which protect it; the clownfish cleans the anemone and drives away fish that eat it. This is …
  1. Amutualism
  2. Bcommensalism
  3. Cparasitism
5.Match each relationship to its effect on the two organisms.
  • mutualism
  • commensalism
  • parasitism
  • predation
  • one benefits, the other is unaffected
  • one benefits, the other is harmed
  • one organism hunts, kills and eats the other
  • both organisms benefit

Part B: Competition

6.Tall trees in a forest compete with smaller plants for light. ☐ True   ☐ False
7.Competition only happens between different species. ☐ True   ☐ False
8.When two species compete for the same food supply, the numbers of one or both species may be lower than if each lived there alone. ☐ True   ☐ False
9.An organism that lives on or in another organism and harms it is called a (answer space).

Part C: Predators and prey

Use the data to answer the questions.

Rabbit and fox populations in a valley (one survey each spring)

Survey 1: rabbits 200, foxes 10

Survey 2: rabbits 400, foxes 15

Survey 3: rabbits 600, foxes 30

Survey 4: rabbits 300, foxes 45

Survey 5: rabbits 150, foxes 25

Survey 6: rabbits 250, foxes 12

10.In which survey did the rabbit population peak, and in which survey did the fox population peak? (answer space)
11.By how much did the rabbit population change from survey 3 to survey 4? (answer space)
12.Explain why the fox population rose between surveys 2 and 4. (answer space)
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Preview — the PDF contains the full resource and answer sheet.

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About this resource

Created by
Success Tutoring Science Team
Last reviewed
1 October 2026
How it was made
Written by our team

Free to print and share for personal, classroom and homeschool use. Please don't resell. Spotted an error? Let us know.