Cellularlife on earth can be divided in three different domains – the eukaryotic, prokaryoticand archaea, within these, further sub distinctions can be made, resulting in abranched and complex annotation of life. Fungi belong to the eukaryotic domain, inwhich they constitute their own kingdom, besides the plant and animal kingdoms.As other eukaryotic cells, fungi cells accommodate organelles and a truenucleus, all contained within a membrane, while they differ by having a cellwall consisting of chitin, as well as lacking chlorophyll. The general schemeof a fungi is relatively simple.
Composing of a main body, a mycelium, made upby a branched network of tubes, hyphae. Through hyphae, nutrients are absorbed,in which organic carbon, from either living or dead biological organisms,function as the main energy source. Reproduction of fungi can occur in two separate,yet connected, ways. Either reproduction takes place asexually, mainly through themeans of the release of small identical copies of parent fungi as spores, orreproduction occurs sexually. Sexual reproduction varies between differentphylums and therefore a generic description does not make sense.
Instead adetailed description is integrated within the description of each phylum. The fungikingdom can be subdivided in 5 different phyla, these are named Chytridiomycota, Zygomycota, Ascomycota, Basidiomycota and Deuteromycota. Phylum Chytridiomycotaencompasses most fungi, which at some point in their life cycles exists as flagellatedswimming cells and these fungi are therefore, primarily, found in aquaticenvironments. These fungi reproduce asexually whena zoospore lands on a substrate, after which a cell wall forms around it, leadingto formation of a fungi body. Long threads, rhizoids, attach to the substrateand through these nutrient is absorbed. After a period of feeding, the fungibody is converted into a sporangium, a structure which contains andsubsequently releases zoospores. Sexual reproduction occurs by fusing zoospores,thus creating a diploid zygote, which then hardens and creates ameiosporangium. Later fusing of nuclei create meiospores, which can then swimaway and form a new fungi body.
Fungi of this phyla are mostly harmless,saprotrophic fungi, although a few pathogens such as Batrachochytrium dendrobatidis, which causes chytridiomycosis in amphibious animalshave been found. asd