Organisms within an ecosystem can be classed as producers, consumers or decomposers. Energy flows through these organisms within the ecosystem.
Producers, such as a trees, produce their own food and begin this cycle. Using energy from the sun they produce food. They do this by photosynthesis. Most producers are plants, but there are some small organisms that produce food through photosynthesis as well.
The producers are eaten by primary consumers that cannot produce their own food, such as a giraffe. Primary consumers are herbivores which means they only eat plants. Secondary consumers are carnivores such as lions. In a simple food chain secondary consumers eat primary consumers.
Decomposers and break down dead plants and animals. They also break down the waste of other organisms. Examples of decomposers include bacteria and fungi. Decomposers get their energy from breaking down dead material e.g. dead producers, dead consumers or fallen leaves. When dead material is decomposed nutrients are released into the soil. These nutrients are then taken up from the soil by plants. Decomposers are very important for any ecosystem. If they weren’t in the ecosystem the plants would not get essential nutrients and dead matter and waste would gather.
A food chain shows the relationships between these feeding groups. They show the flow of energy from producer to tertiary consumer. The image below illustrates this.
A food chain
A food web shows lots of food chains and how they overlap.
A food web
The transfer of nutrients through the ecosystem is known as the nutrient cycle.
The Nutrient Cycle
The nutrient cycle shows pathways through which nutrients are constantly recycled. All plants and animals depend on nutrients in food for their survival.