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Auralith Learning

Year 8 · Science · Ecosystems and photosynthesis · Lesson 1

Food chains and food webs

Food chains and food webs, producers and consumers, predicting the effects of changes in a food web, energy loss, and bioaccumulation.

Whiteboard video lesson: Food chains and food webs

23-minute video lesson

Teaching, worked examples and 20 practice questions solved step by step.

Watch free for a month

What your child will learn

  • Describe food chains and what the arrows show
  • Identify producers, consumers, predators and prey
  • Use food webs to predict the effect of changes
  • Explain why energy is lost along a food chain
  • Describe bioaccumulation

The method

  1. Arrows in a food chain show the flow of energy, pointing to the eater.
  2. Producer → primary consumer → secondary consumer → top predator.
  3. In a food web, changing one species affects others (interdependence).
  4. Energy is lost at each level; poisons build up along a chain (bioaccumulation).

Key words: food chain, food web, producer, consumer, herbivore, carnivore, predator, prey, interdependence, bioaccumulation.

Worked examples

The first three practice questions from the lesson, with every step.

Question 1

What is a producer?

  1. Step 1: An organism that makes its own food
  2. Step 2: Usually a green plant, by photosynthesis

Answer: An organism that makes its own food (e.g. a plant)

Question 2

What is a consumer?

  1. Step 1: An animal that eats other organisms

Answer: An organism that eats other organisms

Question 3

What is the difference between a herbivore and a carnivore?

  1. Step 1: Herbivore: eats plants
  2. Step 2: Carnivore: eats animals

Answer: Herbivores eat plants; carnivores eat animals