The Columbia Encyclopedia, Sixth Edition. Columbia Encyclopedia World Factbook American Heritage Coll. The cell walls of fungi are of chitin or other noncellulose compounds. In many ways fungi are more closely related to animals than to plants, and they have been thought to share a common protist ancestor with animals. 1 Most fungi are capable of asexual and sexual reproduction .
Asexual reproduction is by fragmentation or spore formation.
Those that reproduce sexually produce gametes in specialized areas of the hyphae called gametangia. The gametes may be released to fuse into spores elsewhere, or the gametangia themselves may fuse. Typically they release digestive enzymes onto a food source, partially dissolving it to make the necessary organic or inorganic nutrients available. Some parasitic types obtain their food directly from the cells of a living food source. Some fungi are pathogenic to humans and other animals.