This key facts covers Food Chains and Food Webs within Ecosystems Communities for GCSE Biology. Topic 1: Ecosystems Communities It is section 5 of 15 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
📋 Food Chains and Food Webs
Example Food Chain
Grass → Rabbit → Fox → Eagle
The arrows show the direction of energy transfer — from one organism to the next. Each step is a trophic level:
- Producer (trophic level 1): Grass — makes its own food by photosynthesis
- Primary consumer (trophic level 2): Rabbit — eats the producer
- Secondary consumer (trophic level 3): Fox — eats the primary consumer
- Tertiary consumer (trophic level 4): Eagle — eats the secondary consumer
Food Webs
A food web shows multiple interconnected food chains in an ecosystem. Food webs are more realistic than single food chains because most organisms eat more than one thing and are eaten by more than one predator.
Exam question type: "What would happen if all the rabbits were removed?" → Follow the arrows: foxes lose a food source (population decreases), grass population increases (less herbivory), other prey species may decrease (foxes switch to eating them).
Practice questions for Ecosystems Communities
What is a community in ecology?
Explain what is meant by interdependence in an ecosystem.