In this lesson we will learn about producers, consumers, and decomposers.
Find out what they are and how they interact with one another in the ecosystem.
The Circle of Life
Imagine the circle of life that takes place on an African savanna. The grass grows and is eaten by an antelope. The antelope is caught and eaten by a cheetah. The cheetah dies, is eaten by bacteria, and nutrients are returned to the soil. These nutrients are used by the grass as it continues to grow on the savannah.
Each organism has a purpose. Like this example, there is a simple pattern of energy flow through organisms in any ecosystem. What are other examples you can think of?There are three main groups to consider when looking at the circle of life in an ecosystem. The groups are producers, consumers, and decomposers. These groups are based on how the organism obtains food.
Producers, consumers, and decomposers all interrelate in food chains and food webs and are dependent on one another for survival.
Producers make their own food. They do not have to obtain energy from other organisms. They obtain their energy from the sun and make food with that energy through the process of photosynthesis. Producers may also be called autotrophs.
Most producers are plants, but there are some small organisms that produce food through photosynthesis as well. Producers are at the beginning of any simple food chain. On the African savanna, examples of producers would be any of the plants that grow there.
Consumers cannot make food. They must find food and eat it to obtain energy.
Consumers may also be called heterotrophs. There are primary and secondary consumers. Primary consumers are the next link in a simple food chain. These are the plant eaters, or herbivores. They do not eat other animals. In addition to the antelope mentioned earlier, examples of primary consumers on the African savanna would be a wild boar or a giraffe.Secondary consumers follow primary consumers in a simple food chain.
Secondary consumers eat the primary consumers. Secondary consumers can be carnivores or omnivores. Carnivores eat only meat, while omnivores eat both meat and plants. In addition to the cheetah, secondary consumers on the African savanna can include a lion who kills and eats the giraffe, or a human who kills and eats the wild boar.
Decomposers are the last link in a simple food chain.
They may also be called saprobes. Decomposers eat decaying organic material. If an animal dies, it is eaten by decomposers. If a tree loses a leaf, they eat that as well. They get rid of anything that is no longer alive by breaking it down into simple nutrients and returning it to the soil. These nutrients will then be used by producers and the cycle will begin again. Examples of decomposers on the African savanna can include termites that eat a fallen tree in addition to bacteria that eat the remains of dead animals.
Let’s review! A pattern of energy flow through the organisms that live in any ecosystem can be observed. Producers, such as a tree, make their own food and begin this cycle. The producers are then eaten by primary consumers that cannot produce their own food, such as a giraffe. Primary consumers only eat plants.
Secondary consumers are meat eaters, like lions. They eat the primary consumers. When the primary consumer dies it is eaten by decomposers. This returns nutrients to the soil to help begin the circle of life again.
Producers – living organisms that make their own foodPhotosynthesis – the process by which producers obtain their energy from the sun and make food with that energyAutotrophs – another name for producersConsumers – living organisms that cannot make foodHeterotrophs – another name for consumersPrimary consumers – the link to producers in a simple food chain; living organisms that consume producersHerbivores – primary consumers; plant eatersSecondary consumers – the link to primary consumers in a simple food chain; living organisms that consume primary consumersCarnivores – animals that only eat meat; secondary consumersOmnivores – animals which eat both meat and plants; also considered secondary consumersDecomposers – circular link between consumers and producers in a simple food chain; decompose the bodies of consumers and turn them into nutrients, which are then available for producersSaprobes – another name for decomposers
After this lesson, check to see if you can do the following:
- Define producers, primary and secondary consumers, and decomposers
- Identify examples of each in an ecosystem