Producers such as green plants use light to make organic matter. Consumers obtain organic matter by eating organisms or their products. Decomposers, including many fungi and bacteria, break down dead material and waste. A food chain shows one feeding pathway; a food web combines connected pathways.
Here, arrows point from food to feeder, showing the direction of matter and energy transfer. Grass → rabbit means the rabbit eats grass. A predator may also be prey in another link. An omnivore consumes both plant and animal material and may occupy different feeding levels. Decomposers receive material from many levels, not just the final predator.
Example 1
In algae → small fish → pelican, identify the producer and the consumer that eats fish.
Algae are the producer. The pelican is the fish-eating consumer; arrows point toward the receiver.
Example 2
A fox eats both rabbits and berries. Why is one straight chain incomplete?
It leaves out one feeding pathway. The fox is an omnivore with links to animal and plant food sources.
Watch out: In the convention used here, arrows point from food to feeder, showing transfer of matter and energy.