Trophic Levels (OCR GCSE Biology A (Gateway Science Suite)): Revision Notes
📚 Revision Notes
7.4.1 Trophic Levels
infoNote
Trophic levels represent the different stages in a food chain, where energy is transferred from one level to the next.
- Level 1: Producers
- Organisms at the first trophic level are called producers.
- These are typically plants and algae, which make their own food through photosynthesis.
- Level 2: Primary Consumers
- Organisms at the second trophic level are known as primary consumers.
- These are herbivores that feed exclusively on producers (plants).
- Level 3: Secondary Consumers
- Organisms at the third trophic level are called secondary consumers.
- These are carnivores that eat primary consumers (herbivores).
- Level 4: Tertiary Consumers
- Organisms at the fourth trophic level are known as tertiary consumers.
- These are carnivores that eat other carnivores, specifically secondary consumers.
- Apex predators are at the top of the food chain with no natural predators.
Decomposers
- Role: Decomposers, such as bacteria and fungi, break down dead plant and animal matter, recycling nutrients back into the ecosystem.
- Process: They secrete enzymes that break down complex organic material into small, soluble molecules.
- Absorption: These soluble molecules are then absorbed into the decomposers through diffusion.