Ecosystems are complex webs of interaction between organisms.
Producers
Producer organisms are able to produce sugar using nutrients from decomposers, sunlight, carbon dioxide, and water. Producers are the source of food for all organisms on earth.
In this diagram, the producer is grass because grass produces its own food.
Consumers
Consumers are organisms that cannot make their own food. Consumers that eat only plants are known as herbivores and consumers that eat only animals are known as carnivores. When a consumer eats both plants and animals they are known as an omnivore.
In this diagram, the consumer is a cow because it consumes grass as food.
Decomposers
These organisms break down dead organisms into raw materials that can be used by producers.
In this diagram, the decomposer is a worm that breaks down dead organisms into raw materials.