Description of Fungi
The term fungus has more than one meaning. It is best limited to members of the kingdom Fungi - in which the normal trophic form is a system of filaments or mycelia and from which spores are occasionally produced. Feeding usually occurs through the mycelia, and the spores usually facilitate distribution and help the fungus colonize new habitats. The true fungi have their evolutionary origins within the chytrids (some taxonomists include these within the fungi). In addition to the true fungi, a number of other evolutionary lineages have produced fungus-like organisms. The most similar are the oomycetes, a lineage that is related to diatoms and brown algae - all being members of the stramenopiles. Other fungus-like organisms include amoeboid slime moulds. The true fungi are heterotrophic organisms. The cytoplasm is enclosed within a chitinous cell wall. While the majority of species grow as multicellular filaments called hyphae, with all of the hyphae together form a mycelium, some species (such as yeasts) also grow as single cells. Sexual and asexual reproduction of the fungi is commonly via spores, often produced on specialized structures (mushrooms). Some species have lost the ability to form specialized reproductive structures, and propagate solely by vegetative growth. Yeasts, moulds (molds), and mushrooms are examples of fungi. The fungi are more closely related to animals than plants, even though the discipline devoted to the study of fungi, known as mycology, often falls under botany. True fungi lack flagella, but the chytrid ancestors are unicellular organisms that swim using flagella. Occurring worldwide, most fungi are largely invisible to the naked eye, living for the most part in soil, dead matter, and as symbionts of plants, animals, or other fungi. They perform an essential role in many ecosystems in decomposing organic matter and are indispensable in nutrient cycling and exchange. Some fungi become noticeable when fruiting, either as mushrooms or moulds. Many fungal species have long been used as a direct source of food, such as mushrooms and truffles and in production of bread, and in fermentation of various food products, such as wine, beer, and soy sauce. Fungi are sources for antibiotics (such as penicillin) used in medicine and for various enzymes such as cellulases, pectinases, and proteases important for industrial use or as active ingredients of detergents. Many fungi produce bioactive compounds called mycotoxins, such as alkaloids and polyketides that are toxic to animals including humans. Some fungi are used for hallucinogenic effects. Several species of the fungi are significant pathogens of humans and other animals, and losses of crops due to fungal diseases (e.g., rice blast disease) or food spoilage caused by fungi can have a large impact on human food supply and local economies.
I am not sure how this description got to be in Bio*pedia (for which I am responsible), but I have now made some changes to it. If you wish you can register with starcentral.mbl.edu/biopedia and make further changes directly in that environment (please send an email to firstname.lastname@example.org when you register). It is possible to generate alternative descriptions within Bio*edia or elsewhere, but I recommend that we work collaboratively to improve the text so that it best meets our needs.
@Priscila Chaverri: This text is released under a creative commons license, so you are free to revise and improve it. The license allows you to create a new text article (= a derivative work) that uses the original text verbatim except for the bits that need improvement. See Fixing errors in text articles for more information.
There is something wrong or unclear from this statement: "A number of independent types of organisms have been referred to as protists - including amoeboid slime moulds, the oomycetes that are related to diatoms and brown algae, and the true fungi that are related (or, according to some, include) chytrids." First, chytrids ARE fungi. Second, the sentence needs to be re-written to clarify that these organisms, the protists, are not true fungi and that at some point in history they were.