Food chains show how organisms feed on one another. This cycle of feeding moves energy and nutrients throughout ecosystems. Fungi act as decomposers within the food chain; they reboot the cycle by breaking down dead waste matter into its component parts, so that it is ready to be taken up again into new growth.
Producers and Consumers
The individual organisms that make up food chains, such as shrubs, deer, and mountain lions, are organized into “trophic levels” that indicate where an organism fits along the chain. Producers -- mostly plants -- begin the chain. They combine nutrients with energy from sources like sunlight to create their own food. The next several trophic levels are all called consumers. Primary consumers -- herbivores or omnivores -- eat the producers. The chain grows as additional consumers (secondary, tertiary, etc.) feed on one another, until a top predator like a mountain lion -- an animal with no natural predators – ends the cycle.
Decomposers make up the final trophic level. When organisms produce waste or die, they leave behind non-living matter. Locked within this material are nutrients and organic matter. Decomposers like fungi break waste down and transform it back into raw nutrients. Fungi grow on and in the dead matter that they consume. As they grow, they release enzymes that digest the dead matter in which they are growing, and then they absorb the released nutrients into themselves.
Renewing the Landscape
By breaking down dead matter, decomposers like fungi clear the environment of excess debris. Once they have finished consuming their growing medium, their part in the food chain is complete. At this point, the nutrients that they have reclaimed from dead matter are ready to begin a new food chain.
Restarting the Cycle
Some fungi are eaten directly by consumers. For example, people eat mushrooms. In this case, fungi directly start new food chains and transfer their collected energy and nutrients to consumers. In other cases, fungi become part of the soil, enriching it with the nutrients that they have consumed. This allows a new generation of producers to create food, which will then feed generations of consumers. Fungi are part of the special group of decomposers that allow this cycle to renew itself.
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