# A food web in a grassland ecosystem contains the following organisms: grass, grasshoppers, frogs, and hawks. Describe the roles of the grass and the grasshoppers in this food web, and explain why a pyramid of biomass for this food web would be wider at the base than at the top.

> Pearson Edexcel International GCSE Biology (4BI1) — 4.2 Feeding relationships · Describe and Explain · 4 marks

> In a grassland ecosystem, grass is eaten by grasshoppers, grasshoppers are eaten by frogs, and frogs are eaten by hawks.

## Mark scheme (4 marks)

1. Grass is the producer / photosynthetic organism that provides biomass for all living things / is at the start of the food chain (trophic level 1).
2. Grasshoppers are primary consumers / herbivores at trophic level 2 that feed on the producer.
3. Only around 10% of the energy / biomass is transferred from one trophic level to the next.
4. Therefore the dry mass of living material at each trophic level decreases from producer to tertiary consumer, so the pyramid is widest at the base (grass) and narrowest at the top (hawks).

## Key terms

- [pyramid of biomass](https://www.gradenine.co.uk/glossary/pyramid-of-biomass)
- [food web](https://www.gradenine.co.uk/glossary/food-web)

## Related

- [Revision notes for Pearson Edexcel International GCSE Biology (4BI1)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-food-web-in-a-grassland-c493d95d) · Published by Druglandscape Ltd.