Chapter focus
Explore how organisms interact with one another and with non-living parts of an ecosystem, and why biodiversity supports stability.
These are original study notes and practice questions prepared for revision. Use your assigned NCERT edition for the complete lesson, diagrams, activities, and exercise wording.
What you will learn
- Explain the main idea: Explore how organisms interact with one another and with non-living parts of an ecosystem, and why biodiversity supports stability.
- Use the key terms and relationships in the notes below.
- Show your reasoning and check whether an answer fits the question.
Key ideas and notes
- A food chain shows one pathway of energy transfer; food webs show connected pathways.
- Producers make food, consumers obtain it by eating other organisms, and decomposers break down dead material.
- A change to one population can affect other parts of a food web.
Worked example
If a predator decreases, its prey may increase, which can then affect the plants the prey eats.
Quick revision
A food chain shows one pathway of energy transfer; food webs show connected pathways.
Producers make food, consumers obtain it by eating other organisms, and decomposers break down dead material.
A change to one population can affect other parts of a food web.
Original practice questions
Try each question first. Open the answer to check your reasoning.
What is a producer in a green ecosystem?
Answer: A green plant or algae that makes its own food.
What do decomposers return to the environment?
Answer: Nutrients from dead matter and waste.
Why is a food web more realistic than one food chain?
Answer: Organisms usually have several food sources and predators.
Chapter summary
Explore how organisms interact with one another and with non-living parts of an ecosystem, and why biodiversity supports stability. The key ideas above give you a short revision path; practise explaining them in your own words and revisit any step you could not justify.