What roles do fungi play in the environment?
Most fungi serve as decomposers in the environment. They are able to absorb nutrients from decaying organic matter and recycle those chemicals back into the environment. In many cases, this process occurs through a mutualistic relationship. Fungi attach themselves to the roots of plants so that the key elements such as carbon, nitrogen and phosphorus are recycled become readily available for the plant. In return, the plant provides the fungus with sugar.
Some fungi, however, serve as parasites. In these relationships, the fungus still absorbs nutrients, but does so from living organisms. By taking nutrition from another organism, the fungus affects the fitness of that individual in a negative way.
Fungi play the role of predator and prey in the environment. While some fungi are regularly eaten by other organisms, others are actually able to use specialized loops in their hyphae to lasso worms and insects for ingestion.