Fungi obtain food by breaking down and consuming organic material. Most fungi decompose dead organisms, while some are mutualistic or parasitic with other organisms. Fungi store energy in a similar manner to animals.
Fungi include organisms, such as yeast, mold and mushrooms. Most fungi are multicellular, except for yeast. All fungi rely on other organisms to obtain food, and most do so by digesting dead material. This ability makes them important decomposers in many ecosystems. An excellent example of fungal nutrition is the appearance of mushrooms on fallen logs in a forest. The visible part of the mushroom is actually the reproductive structure. The feeding structures, or hyphae, reach deep into the rotting wood to obtain nutrients.
Fungi help break down dead organic material and return nutrients to the soil for use in the ecosystem. Some fungi cohabit with other organisms in such a way that both benefit. An example of this is the mutualistic relationship between fungi and algae to form a lichen. The algae undergo photosynthesis and provide nutrients for both algae and fungus, while the fungus protects the algae. Recent research suggests that some algae grow more successfully when separated from their fungal partner, implying that some lichens are examples of parasitism. A better example of fungal parasitism is Pseudogymnoascus destructans, the fungus responsible for causing white-nose syndrome in hibernating bats. This fungus is opportunistic and capable of feeding on either dead or living tissue. In living bats, it penetrates the skin and robs the bat of vital nutrients and electrolytes.