Information AboutSpore |
| CATEGORIES ABOUT SPORE | |
| plant reproduction | |
| reproduction | |
| germ cells | |
| fungal morphology and anatomy | |
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In Biology , a spore is a Reproductive structure that is adapted for Dispersion and surviving for extended periods of time in unfavorable conditions. Spores form part of the Life Cycles of many Plant s, Algae , Fungi and some Protozoan s.http://www.pollenplus.com/spores/faq.html Spores are usually Haploid and Unicellular and are produced by Meiosis in the Sporophyte . Once conditions are favorable, the spore can develop into a new Organism using Mitotic division, producing a Multicellular Gametophyte , which eventually go on to produce Gamete s. Two gametes fuse to create a new sporophyte. This cycle is known as Alternation Of Generations , but a better term is "biological life cycle", as there may be more than one phase and so it cannot be an alternation. Haploid spores produced by Mitosis (known as Mitospore s) are used by many fungi for asexual reproduction. Spores are the units of ''asexual'' reproduction as a single spore develops into a new organism. By contrast, gametes are the units of ''sexual'' reproduction as two gametes need to fuse to create a new organism. The term ''spore'' may also refer to the dormant stage of some Bacteria or Archaea ; however these are more correctly known as Endospore s and are not truly spores in the sense discussed in this article. The term can also be loosely applied to some Animal resting stages. Fungi that produce spores are known as ''sporogenous'', and those that do not are ''asporogenous''. The term derives from the Ancient Greek word σπορα, meaning Seed . CLASSIFICATION Spores can be classified in several ways. By function Diaspores are dispersal units of Fungi , Moss es, Fern s, Fern Allies , and some other Plant s. In fungi, Chlamydospore s are thick-walled resting spores, and Zygospores are thick-walled resting spores (hypno Zygote s) of Zygomycetous fungi which are produced by sexual gametocystogamy and can give rise to a conidiophore ("zygosporangium") with asexual conidiospores. By spore-producing structure In fungi and fungus-like organisms, spores are often classified by the structure in which meiosis and spore production takes place, such as a Telium , Ascus , Basidium , or Oogonium , which produce Teliospore , Ascospores , Basidiospores , and Oospore s, respectively. Since fungi are often classified according to their spore-producing structures, these spores are often characteristic of a particular taxon of the fungi, such as Ascomycota or Basidiomycota . By origin during life cycle (macrospore) formation in Plant s.]] formation in Plant s.]] Meiospores are the product of Meiosis (the critical cytogenetic stage of Sex ual reproduction), meaning that they are Haploid , and give rise to a haploid daughter cell(s) or a haploid individual. An example is the parent of Gametophyte s of the higher vascular plants ( Angiosperms and Gymnosperm s)—the '''microspores''' (give rise to Pollen ) and '''megaspores''' (or '''macrospores''') (give rise to Ovule s) found in Flower s and Cones ; these plants accomplish dispersal by means of Seed s. A Mitospore ( Conidium , conidiospore) is an asexually produced propagule, the result of Mitosis . Most Fungi produce mitospores. Mitosporic fungi are also known as anamophic fungi (compare Teleomorph or Deuteromycetes ). By motility Spores can be differentiated by whether they can Move or not. Zoospore can move by means of one or more Flagella , and can be found in some Algae and Fungi . Aplanospore cannot move, but may potentially grow flagella. Autospore cannot move and cannot develop flagella. Ballistospore are actively discharged from the body of a fungal fruit (such as a Mushroom ). Statismospore are not actively discharged from the fungal fruit body, similarly to a Puffball . PARLANCE In common parlance, the difference between "spore" and " Gamete " (both together called Gonite s) is that a spore will germinate and develop into a Sporeling , while a gamete needs to combine with another gamete before developing further. However, the terms are somewhat interchangeable when referring to gametes. A chief difference between spores and seeds as Dispersal Units is that spores have very little stored food resources compared with seeds, and thus require more favorable conditions in order to successfully germinate. Seeds, therefore, are more resistant to harsh conditions and require less Energy to start Mitosis . Spores are usually produced in large numbers to increase the chance of a spore surviving. The Endospores of certain bacteria are often incorrectly called spores, as seen in the 2001 Anthrax Attacks where the media called anthrax endospores "anthrax spores". Unlike eukaryotic spores, endospores are primarily a survival mechanism, not a reproductive method, and a bacterium only produces a single endospore. DIASPORES In the case of spore-shedding Vascular Plant s such as Fern s, wind distribution of very light spores provides great capacity for dispersal. Also, spores are less subject to animal predation than seeds because they contain almost no food reserve; however they are more subject to fungal and bacterial predation. Their chief advantage is that, of all forms of progeny, spores require the least energy and materials to produce. Vascular plant spores are always " spore and the smaller functioning as a " Male ". Under high Magnification , spores can be categorized as either monolete spores or '''trilete spores'''. In monolete spores, there is a single line on the spore indicating the axis on which the mother spore was split into four along a vertical axis. In trilete spores, all four spores share a common origin and are in contact with each other, so when they separate each spore shows three lines radiating from a center pole. FUNGAL SPORES Parasitic fungal spores may be classified into internal spores, which germinate within the a host, and '''external spores''', also called '''environmental spores''', released by the host to infest other hosts. {Link without Title} SEE ALSO REFERENCES |
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