In the example, grass seeds are eaten by voles, and voles are eaten by barn owls. The arrows between each organism in the chain always point in the direction of energy flow from the food to the feeder.
The Sun is the ultimate source of energy for most communities of living things. Green plants are usually the producers in a food chain.
Producers are organisms that make their own organic nutrients (food) - usually using energy from sunlight. Green plants make their food by photosynthesis. The other organisms in a food chain are consumers, because they all get their energy by consuming other organisms.
|Organism||How it gets its energy|
|Consumer||Feeding on other organisms|
|Primary consumer||Eating plants|
|Secondary consumer||Eating primary consumers|
|Tertiary consumer||Eating secondary consumers|
|Carnivore||Eating other animals|
|Decomposer||Feeding on dead and decaying organisms, and on the undigested parts of plant and animal matter in faeces|