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GCSE Biology · key term
A sequence showing how biomass and chemical energy are transferred between organisms by feeding.
Used by AQA and OCR
Specification 4.7.2.1 · Paper 2
A sequence showing feeding relationships between organisms, with arrows pointing from the organism eaten to the organism that eats it.
Revise: Food Chains and Predator-Prey RelationshipsA food chain is a simple representation of one route through these feeding relationships.
Specification B1.4a, B4.1h · Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
A sequence showing how biomass and its stored chemical energy are transferred when organisms eat other organisms.
Revise: Photosynthetic organismsThe same reasoning applies to longer food chains and aquatic ecosystems. Algae produce biomass that can feed small aquatic consumers, which may then be eaten by fish and larger predators. Photosynthetic organisms are therefore the main producers of food and biomass for life on Earth: they introduce newly made organic material into most food chains.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
A sequence showing which organisms eat others, beginning with a producer.
Revise: Trophic LevelsA trophic level is a feeding position in a food chain. The chain begins with a producer, usually a green plant or alga. Through photosynthesis, producers make glucose and use it to build the biological material, or biomass, that makes up their bodies.
When explaining why photosynthetic organisms are important, link the ideas in order: photosynthesis makes organic food, some of this becomes biomass, and that biomass supplies consumers through food chains.
In a food chain, arrows point from the organism being eaten to the organism that eats it: they show the direction of biomass transfer.
Identify a consumer’s trophic level from what it eats in the particular food chain, not from its size or whether it is a predator.
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