You will learn
- Define environment and ecosystem.
- Describe food chains.
- Define biodiversity.
- Describe Sierra Leone environments.
Version 0.2 · expanded edition · built from cited public sources Content is based on the official frameworks and sources listed under Sources and standards. No official endorsement is claimed. Written in the style of common primary school assessments. No exam result is promised.
Student lesson
- Environments have living and non-living parts.
- Food chains pass energy along.
- Decomposers recycle nutrients.
- Biodiversity makes ecosystems strong.
Words to know
a community of living things and the non-living things around them
a line showing how energy passes from one living thing to another by eating
a living thing, like a fungus or bacterium, that breaks down dead plants and animals
the variety of living things in a place
1. Discover: One log, many lives
Mr Cole puts a rotting log on a tray in the class, inside a plastic box so nobody touches it. “Look closely,” he says. “Moss grows on the top. Small insects live under the bark. Fungi are breaking the wood down into soil.” Mei counts the living things. “There are at least six kinds. A tiny ecosystem!” “Every living thing needs others,” says Mr Cole. “That is why variety matters.”
Think: What would happen to the log’s ecosystem if the fungi disappeared?
2. Understand: Ecosystems
Idea 1: What an ecosystem is
An ecosystem is a community of living things and the non-living things around them, such as soil, water, air, sunlight and rock. Forests, grasslands, wetlands, rivers, oceans, deserts, mountains and polar lands are different natural environments. Each has its own plants and animals.
Idea 2: Food chains
A food chain shows how energy moves: plants (producers) make food from sunlight; animals (consumers) eat plants or other animals; decomposers such as fungi and bacteria break down dead things and return nutrients to the soil. Remove one link and the whole chain can be affected.
Idea 3: Biodiversity in Sierra Leone
Biodiversity is the variety of life. Sierra Leone has rainforest in the south-east, savanna in the north, mangroves along the coast and rivers, and rich waters in the Atlantic. Chimpanzees, forest elephants, pygmy hippos, many birds and countless plants live in these places.
3. Worked examples
Example 1 (I show you): Define
Ecosystem.
- Think.
- Say.
- Check.
Answer: Living and non-living things.
Example 2 (We do it together): Order
A food chain.
- Think.
- Order.
- Say.
Answer: Grass, antelope, lion.
Example 3 (You try): Name
A decomposer.
Show the steps and answer
- Think.
- Say.
- Check.
Answer: Fungus.
Did you know?
Mangrove forests along tropical coasts are among the most productive ecosystems, sheltering young fish, crabs and oysters among their roots.
Why this matters
Healthy ecosystems provide food, clean water and air, and protect people.
4. Explore: Food web
Draw a food chain for a forest or river with at least four links. Add a decomposer. Then show what could happen if one link disappeared.
- Draw.
- Add.
- Predict.
- Share.
Think about it: what did you notice?
What did you notice? Every link matters.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- An ecosystem is ___.
- A food chain is ___.
- A decomposer is ___.
- Biodiversity is ___.
Guided practice
Question 1. What is an ecosystem?
Living and non-living community.
Question 2. What is a food chain?
Energy passed by eating.
Question 3. What is a decomposer?
Breaks down dead things.
Independent practice
Level 1: Start
- What is an ecosystem?
- What is a food chain?
- What is a decomposer?
- What is biodiversity?
- Name an environment.
Level 2: Grow
- Why decomposers?
- Why variety?
- Why protect habitats?
Level 3: Stretch
- Draw a chain.
- Add a decomposer.
- Predict a change.
Answers are in the answer key below. Try first, then check.
6. Apply: Social Studies in everyday life
Name two parts of an ecosystem and give a short food chain.
Show a sample answer
Plants, water; grass, antelope, lion.
Another one. Look at a patch of ground and list living and non-living things.
Show a sample answer
Share.
7. Common mistakes
Fix: Plants, soil and water count too.
Fix: They recycle nutrients.
8. Lesson summary and revision card
- I can define environment and ecosystem.
- I can describe food chains.
- I can define biodiversity.
- I can describe Sierra Leone environments.
9. Check and master
Answer all 14 questions. You will see feedback after each one.
Your result appears here after you answer every question.
10. Key takeaways
- Environments have living and non-living parts.
- Food chains pass energy along.
- Decomposers recycle nutrients.
- Biodiversity makes ecosystems strong.
11. Next lesson
Next lesson: Human land use. Keep going with the next idea in this course.
Exam practice
These questions are written in the style of common school and international primary assessments. Try them on your own, without looking back. Then check your answers in the marking guide. The marks are shown in brackets.
- Define ecosystem and decomposer. [2 marks]
- Draw or write a food chain with four links. [3 marks]
- Describe three environments in Sierra Leone. [3 marks]
- Say why biodiversity matters. [2 marks]
Total: 10 marks.
Marking guide and model answers
- Ecosystem [1]; decomposer [1]
- Four links [3]
- Three [3]
- Strong ecosystems [1]; example [1]
Score guide: 9 to 10 = secure. 6 to 8 = nearly there, revise the parts you missed. Under 6 = work through the lesson again with a grown-up.
Printable worksheet
- What is an ecosystem?
- What is a food chain?
- What is a decomposer?
- What is biodiversity?
- Name an environment.
- Why decomposers?
- Why variety?
- Why protect habitats?
- Draw a chain.
- Add a decomposer.
Homework
Draw a food chain.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What is an ecosystem? | Living and non-living community. | 1 |
| 2. What is a food chain? | Energy passed by eating. | 1 |
| 3. What is a decomposer? | Breaks down dead things. | 1 |
| 4. What is biodiversity? | Variety of life. | 1 |
| 5. Name an environment. | Rainforest. | 1 |
| 6. Why decomposers? | Return nutrients. | 1 |
| 7. Why variety? | Stronger ecosystems. | 1 |
| 8. Why protect habitats? | Living things need them. | 1 |
| 9. Draw a chain. | Chain. | 1 |
| 10. Add a decomposer. | Decomposer. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 Living and non-living community.; 2 Energy passed by eating.; 3 Breaks down dead things.; 4 Variety of life.; 5 Rainforest.. Level 2: 1 Return nutrients.; 2 Stronger ecosystems.; 3 Living things need them.. Level 3: 1 Chain.; 2 Decomposer.; 3 Predict..
Quiz answers: 1 B, 2 C, 3 A, 4 B, 5 C, 6 A, 7 B, 8 C, 9 A, 10 B, 11 C, 12 A, Challenge 1 B, Challenge 2 C.
Mastery and remediation
| Objective | Bronze (Developing) | Silver (Proficient) | Gold (Advanced) |
|---|---|---|---|
| O1 Define environment and ecosystem | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O2 Describe food chains | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O3 Define biodiversity | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O4 Describe Sierra Leone environments | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
Courseversity badge thresholds (overall quiz score): Gold = 90–100%; Silver = 80–89.9%; Bronze = 70–79.9%. A badge is never a full record of progress.
If a learner struggles
- Find the misconception: “Only animals are part of an ecosystem.” Plants, soil and water count too.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Make an ecosystem poster.
- Guided practice: work through one example together and let the learner try the next one.
- Reassess: use the quiz again or the worksheet.
- Move on when the learner shows Silver-level evidence independently.
For parents and guardians
In this lesson your child studies ecosystems. Please explore nature safely together. You do not need to be an expert to help.
- Observe nature safely.
- Name animals.
- Protect habitats.
- Ask “how do you know?” after each answer, and listen.
- Praise effort, not only right answers. Mistakes are how we learn.
- Ten to fifteen minutes a day is better than one long session.
Teacher package
1–5. Objectives, prerequisites, materials, preparation, duration
Lesson objectives. Learners will: define environment and ecosystem; describe food chains; define biodiversity; describe Sierra Leone environments.
Prerequisite knowledge. Grade 4 ideas: physical geography, human settlement, resources and landscape change.
Materials. Paper, pencils, pictures. Low-resource options: use chalk or charcoal on a board or wall, drawings in the sand, and objects from the classroom instead of printed materials.
Preparation. Prepare ecosystem pictures.
Suggested duration. 45–60 minutes. It can be split into two shorter sessions.
6–9. Teaching procedure, explanation notes, guided and independent activities
Introduction (5 min). Tell the one log, many lives story.
Explanation (10 min). Teach natural environments.
Guided activity (10 min). Food web.
Independent activity (10 min). Discuss.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. What makes up natural environments and why do they matter?
Teacher explanation notes. Start with a picture, story, map or local example. Then talk about what was seen, then draw and write. Always ask “how do you know?” and invite more than one view. Treat every family, culture and community with respect, and never ask learners to share private information.
10–12. Differentiation, formative assessment, common misconceptions
Support. Use pictures, maps, real objects and short sentences, and let learners work with a partner. Let learners point, show, act or draw instead of writing. Extension. Ask learners to find a new example from their own community and explain how they know.
Formative assessment. Listen to learners read and explain, ask “how do you know?”, and check the independent work.
Misconceptions. “Only animals are part of an ecosystem.” Plants, soil and water count too.
13–15. Assessment questions, answer keys, marking scheme
Use the quiz, the 10-mark exam practice and the worksheet on this page. All answers and marking guides are in the answer sections above. Re-check every answer before use.
16–19. Remediation, enrichment, homework, teacher reflection
Remediation. Make an ecosystem poster. Enrichment. Find one new example near your home or school, draw or write about it and explain it to someone. Homework. See above.
Teacher reflection. After teaching, record: which ideas learners understood; which misconceptions occurred; which activities worked; which learners need more practice; and what to improve next time.
Sources and standards
This lesson is based on the sources below, and no official endorsement is claimed. Reference starting points: NCSS standards and C3 Framework, Cambridge Primary Humanities and the IB Primary Years Programme. Where a standard code is named, it points to the official framework.
Research used to shape this lesson. Courseversity Social Studies curriculum, Grade 4 Unit 9, topic 1; NCSS C3 Framework, human-environment interaction; Cambridge Lower Secondary Humanities, environment and sustainability; IB Primary Years Programme, sharing the planet. These sources informed the lesson.