Fungi - Definition, Types, Examples, Characteristics & Reproduction | Biology Dictionary
Exposure level and distribution characteristics of airborne bacteria and fungi in .. Further statistical analysis revealed that the symbiosis of algae and sludge. For example most terrestrial plants form symbiotic relationships with fungi. an association between a fungus and its photosynthetic partner (usually an alga). Fungi. 1. The fungi are one of the 4 eukaryotic kingdoms. tree of life. 2. Characteristics of fungi Lichens - Symbiotic relationships between lichens and algae.
These are hyphae of a Penicillium fungus. Fungi are heterotrophs; they cannot make their own food and must obtain nutrients from organic material. To do so, they use their hyphae, which elongate and branch off rapidly, allowing the mycelium of the fungus to quickly increase in size.
Some fungi hyphae even form root-like threads called rhizomorphs, which help tether the fungus to the substrate that it grows on while allowing it to quickly obtain more nutrients from other sources.
Fungi are opportunists, which means that they can obtain nutrients from a wide variety of sources and thrive in a wide range of environmental conditions. Some fungi obtain nutrients from dead organic matter; these fungi are called saprobes and are decomposers, which break down and get rid of dead organisms.
MUTUALISMS BETWEEN FUNGI AND ALGAE
Other fungi parasitize plants and are responsible for plant diseases like Dutch elm disease. However, fungi can also have symbiotic mutually beneficial relationships with photosynthetic algae or bacteria, and with plant roots. A symbiotic association of a fungus and an animal that photosynthesizes is called a lichen, while a plant root-and-fungus association is called a mycorrhiza. Fungi Reproduction Most fungi can reproduce through both sexual and asexual reproduction.
Asexual reproduction occurs through the release of spores or through mycelial fragmentation, which is when the mycelium separates into multiple pieces that grow separately. In sexual reproductionseparate individuals fuse their hyphae together. The exact life cycle depends on the species, but generally multicellular fungi have a haploid stage where they have one set of chromosomesa diploid stage, and a dikaryotic stage where they have two sets of chromosomes but the sets remain separate.
All fungi reproduce using spores. Spores are microscopic cells or groups of cells that disperse from their parent fungus, usually through wind or water.
Spores can become dormant for a long time until conditions are favorable for growth. This is an adaptation for opportunism; with a sometimes unpredictable food source availability, spores can be dormant until they are able to colonize a new food source. Fungi produce spores through sexual and asexual reproduction. Types of Fungi There are five phyla of fungi: Chytridiomycota, Zygomycota, Glomeromycota, Ascomycota, and Basidiomycota.
The following is a brief description of each phylum. Chytridiomycota Chytrids, the organisms found in Chytridiomycota, are usually aquatic and microscopic.
They are usually asexual, and produce spores that move around using flagella, small tail-like appendages. Mycelial fragmentation occurs when a fungal mycelium separates into pieces, and each component grows into a separate mycelium.
Mycelial fragmentation and vegetative spores maintain clonal populations adapted to a specific nicheand allow more rapid dispersal than sexual reproduction. Sexual reproduction See also: Mating in fungi and Sexual selection in fungi Sexual reproduction with meiosis has been directly observed in all fungal phyla except Glomeromycota  genetic analysis suggests meiosis in Glomeromycota as well.
It differs in many aspects from sexual reproduction in animals or plants. Differences also exist between fungal groups and can be used to discriminate species by morphological differences in sexual structures and reproductive strategies. Fungi employ two mating systems: In sexually reproducing fungi, compatible individuals may combine by fusing their hyphae together into an interconnected network; this process, anastomosisis required for the initiation of the sexual cycle.
Many ascomycetes and basidiomycetes go through a dikaryotic stage, in which the nuclei inherited from the two parents do not combine immediately after cell fusion, but remain separate in the hyphal cells see heterokaryosis.
During cell divisionformation of the hook ensures proper distribution of the newly divided nuclei into the apical and basal hyphal compartments. An ascus plural asci is then formed, in which karyogamy nuclear fusion occurs. Asci are embedded in an ascocarpor fruiting body.
Karyogamy in the asci is followed immediately by meiosis and the production of ascospores. After dispersal, the ascospores may germinate and form a new haploid mycelium.
Compatible haploid hyphae fuse to produce a dikaryotic mycelium. Yeast is also used in the commercial production of some vitamins.
Fungus - Wikipedia
Neurospora crassaanother favorite "model" organism in the laboratory. The fungal partner in most lichens is an ascomycete. Powdery mildews that attack ornamental plants The chestnut blight, which in a few decades killed almost all of the mature American chestnut trees in the Appalachians of North America. The Dutch elm disease, which has killed many of the American elms in the United States. Pneumocystis jirovecii, which is a major cause of illness in immunosuppressed people, e.
The truffle and the morel, both highly-prized food delicacies. Truffles establish a symbiotic relationship with the roots of such trees as oaks.
bacteria fungi algae: Topics by badz.info
Lichens Lichens are fungi that live in a symbiotic association with an autotrophic green alga or cyanobacterium the "photobiont" or — in some cases — both. Zygomycetes make up the remainder. The relationship is often characterized as mutualistic ; that is, both partners benefit.
But recent evidence e. Recently many lichens have been found to harbor a third partner, a single-celled basidiomycete. Its function remains to be discovered. Lichens secrete a variety of unusual chemicals; some of these probably assist in the breakdown of rock substrates like the one shown here.
The lower image is of the colorful lichen called British soldier. The fungus is Cladonia cristatella, an ascomycete. Its name is the name given to the lichen.
The photobiont is Trebouxia erici, a green alga. It is found in many other lichens as well, and also can be found growing independently. The algal cells eventually are killed by the fungus, but are continuously replaced by new ones. So the relationship in this lichen is one of controlled parasitism rather than mutualism. The red cap produces the spores of the fungus, but these alone cannot form new lichens.
Some lichens release only fungal spores.
These mycobionts depend for their continued survival on finding an acceptable photobiont released from other lichens. Phylogenetic treesbased on both ribosomal RNA genes and many protein-coding genes, as well as fossils indicate that lichens have been present on the earth for at least million years.