Spore 51472 224253037 2008-07-08T00:31:22Z Gracefool 49021 linebreaks {{otheruse|use1=the 2008 video game|page1=Spore (2008 video game)|use2=other uses}} {{refimprove|date=July 2007}} {{expert-subject|biology|date=July 2007}} <!--UNTAGGED 18Oct07: {{Cleanup|date=January 2007}} --> {{tocright}} In [[biology]], a '''spore''' is a [[reproduction|reproductive]] structure that is adapted for [[biological dispersal|dispersal]] and surviving for extended periods of time in unfavorable conditions. Spores form part of the [[Biological life cycle|life cycles]] of many [[plant]]s, [[algae]], [[fungus|fungi]] and some [[protozoan]]s.<ref>[http://www.pollenplus.com/spores/faq.html Spore FAQ - Aerobiology Research Laboratory<!-- Bot generated title -->]</ref> A chief difference between spores and seeds as [[Biological dispersal|dispersal units]] is that spores have very little stored food resources compared with seeds. 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 [[mitosis|mitotic]] division, producing a [[multicellular]] [[gametophyte]], which eventually goes on to produce [[gamete]]s. Two [[gamete]]s 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 a direct alternation. Haploid spores produced by [[mitosis]] (known as [[mitospore]]s) are used by many fungi for asexual reproduction. [[Image:Sporic meiosis.png|thumb|260px|Spores produced in a sporic life cycle.]] Spores are the units of ''asexual'' reproduction, because 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 [[bacterium|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 (''"spora"''), meaning a [[seed]]. ==Classification== Spores can be classified in several ways: ===By spore-producing structure=== In fungi and fungus-like organisms, spores are often classified by the structure in which meiosis and spore production occurs. Since fungi are often classified according to their spore-producing structures, these spores are often characteristic of a particular [[taxon]] of the [[fungi]]. [[Image:Fern spores P1180804.jpg|thumb|[[Fern]] [[sori]], clusters of meiosporangia on the underside of the leaf.]] [[Image:Microspore-formation.svg|thumb|200px|right|In [[plant]]s, [[microspore]]s, and in some cases megaspores, are formed from all four products of meiosis.]] [[Image:Macrospore-formation.svg|thumb|200px|right|In contrast, in many [[seed plant]]s and heterosporous [[fern]]s, only a single product of meiosis will become a [[megaspore]] (macrospore), with the rest degenerating.]] * '''[[Sporangiospore]]s''': spores produced by a [[sporangium]] in many fungi such as [[zygomycete]]s. * '''[[Zygospore]]s''': spores produced by a [[zygosporangium]], characteristic of [[zygomycete]]s. * '''[[Ascospore]]s''': spores produced by an [[ascus]], characteristic of [[ascomycete]]s. * '''[[Basidiospore]]s''': spores produced by a [[basidium]], characteristic of [[basidiomycete]]s. * '''[[Aeciospore]]s''': spores produced by a [[aecium]] in some fungi such as [[Rust (fungus)|rusts]] or [[Smut (fungus)|smuts]]. * '''[[Urediospore]]s''': spores produced by a [[uredinium]] in some fungi such as [[Rust (fungus)|rusts]] or [[Smut (fungus)|smuts]]. * '''[[Teliospore]]s''': spores produced by a [[telium]] in some fungi such as [[Rust (fungus)|rusts]] or [[Smut (fungus)|smuts]]. * '''[[Oospore]]s''': spores produced by a [[oogonium]], characteristic of [[oomycete]]s. * '''[[Carpospore]]s''': spores produced by a [[carposporophyte]], characteristic of [[red algae]]. * '''[[Tetraspore]]s''': spores produced by a [[tetrasporophyte]], characteristic of [[red algae]]. ===By function=== * '''[[Chlamydospore]]s''': thick-walled resting spores of [[fungi]] produced to survive unfavorable conditions. ===By origin during life cycle=== * '''Meiospores''': spores produced by [[meiosis]]; they are thus [[haploid]], and give rise to a haploid daughter cell(s) or a haploid individual. Examples are the precursor cells of [[gametophyte]]s of [[seed plant]]s found in [[flower]]s ([[angiosperm]]s) or [[Conifer cone|cones]] ([[gymnosperm]]s). ** '''[[Microspore]]s''': meiospores that give rise to a male [[gametophyte]], ([[pollen]] in seed plants). ** '''[[Megaspore]]s''' (or '''macrospores'''): meiospores that give rise to a female [[gametophyte]], (an [[ovule]] in seed plants). * '''[[conidium|Mitospores]]''' (or '''conidia''', '''conidiospores'''): spores produced by [[mitosis]]; they are characteristic of [[Ascomycetes]]. Fungi in which only mitospores are found are called “mitosporic fungi” or “anamorphic fungi”, and are previously classified under the [[taxon]] [[Deuteromycota]] (See [[Teleomorph, anamorph and holomorph]]). ===By motility=== Spores can be differentiated by whether they can [[motility|move]] or not. * '''[[Zoospore]]s''': mobile spores that move by means of one or more [[flagellum|flagella]], and can be found in some [[algae]] and [[fungi]]. * '''[[Aplanospore]]s''': immobile spores that may nevertheless potentially grow flagella. * '''[[Autospore]]s''': immobile spores that cannot develop flagella. * '''[[Ballistospore]]s''': spores that are actively discharged from the body of the fungal [[fruiting body]]. Most [[basidiospore]]s are also ballistospores, and another notable example is spores of ''[[Pilobolus]]''. * '''[[Statismospore]]s''': spores that are not actively discharged from the fungal fruiting body. Examples are [[puffball]]s. ==Parlance== In common parlance, the difference between a "spore" and a "[[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 [[Biological dispersal|dispersal units]] is that spores have little food storage compared with seeds, and thus require more favorable conditions in order to successfully germinate. (This is not without its exceptions, however: many [[Orchid#Fruits_and_seeds|orchid seeds]], although multicellular, are microscopic and lack [[endosperm]], and spores of some fungi in the [[Glomeromycota]] commonly exceed 300µm in diameter.)<ref>[http://invam.caf.wvu.edu/fungi/taxonomy/speciesID.htm INVAM]</ref> 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.{{Dubious|date=April 2008}} The [[endospores]] of certain bacteria are often simply 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 [[haploid]] and vascular plants are either '''''homosporous''''' or '''''heterosporous'''''. Plants that are ''homosporous'' produce spores of the same size and type. ''Heterosporous'' plants, such as [[spikemoss]]es, [[Isoëtes|quillwort]]s, and some aquatic ferns produce spores of two different sizes: the larger spore in effect functioning as a "[[female]]" 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. ==Parasitic Fungal spores== Parasitic fungal spores may be classified into '''internal spores''', which germinate within the host, and '''external spores''', also called '''environmental spores''', released by the host to infest other hosts.<ref>[http://www.modares.ac.ir/elearning/Dalimi/Proto/Lectures/week15/biology.htm].</ref> == See also == *[[Media:Fungus spore ejection.ogg|A video of spores being ejected by fungus]] *[[Alternation of generations]] *[[Bioaerosol]] *[[Sporophyte]] *[[Endospore]] *[[Fern]] *[[Auxiliary cell]] ==References== <references/> {{-}} {{Botany}} [[Category:Fungal morphology and anatomy]] [[Category:Germ cells]] [[Category:Plant reproduction]] <!--both; until unicellular cat splits off-->]] [[Category:Reproduction]] [[af:Spoor (plantkunde)]] [[bg:Спора]] [[ca:Espora (vegetal)]] [[cs:Spora]] [[de:Spore]] [[es:Espora]] [[fi:Itiö]] [[fr:Spore]] [[he:נבג]] [[ht:Espò (biyoloji)]] [[hu:Spóra]] [[id:Spora]] [[is:Gró]] [[it:Spora]] [[ja:胞子]] [[ko:포자]] [[lt:Spora]] [[nl:Spore]] [[no:Spore (formering)]] [[pl:Zarodnik]] [[pt:Esporo]] [[ru:Споры]] [[simple:Spore]] [[sk:Výtrus (rozmnožovacie teliesko)]] [[sv:Spor]] [[th:สปอร์]] [[uk:Спора]] [[vi:Bào tử]] [[wa:Spôre]] [[zh:孢子]]