Ciliate and User talk:71.164.28.15: Difference between pages

Revision as of 00:02, 28 December 2005

Revision as of 06:51, 4 July 2007

Line 1:

{{Taxobox_begin | color = khaki | name = Ciliates}}

{{Taxobox_image | image = [[Image:Paramecium.jpg|200px|Paramecium]] | caption = ''[[Paramecium]]''}}

{{Taxobox_begin_placement | color = khaki}}

{{Taxobox_regnum_entry | taxon = [[Protist]]a}}

{{Taxobox_phylum_entry | taxon = '''Ciliophora'''}}<br><small>[[Doflein]] 1901 ''emend.''</small>

{{Taxobox_end_placement}}

{{Taxobox_section_subdivision | color = khaki | plural_taxon = Classes & Subclasses}}

Class [[Karyorelictea]]<br>

Class [[Heterotrich]]ea (e.g. ''[[Stentor (genus)|Stentor]]'')<br>

Class [[Spirotrich]]ea<br>

&nbsp;&nbsp;&nbsp; [[Choreotrich]]ia (e.g. ''[[Tintinnidium]]'')<br>

&nbsp;&nbsp;&nbsp; [[Oligotrich]]ia (e.g. ''[[Halteria]]'')<br>

&nbsp;&nbsp;&nbsp; [[Stichotrich]]ia (e.g. ''[[Stylonychia]]'')<br>

&nbsp;&nbsp;&nbsp; [[Hypotrich]]ia (e.g. ''[[Euplotes]]'')<br>

Class [[Litostomatea]]<br>

&nbsp;&nbsp;&nbsp; [[Haptoria]] (e.g. ''[[Didinium]]'')<br>

&nbsp;&nbsp;&nbsp; [[Trichostome|Trichostomatia]] (e.g. ''[[Balantidium]]'')<br>

Class [[Phyllopharyngea]]<br>

&nbsp;&nbsp;&nbsp; [[Phyllopharyngia]]<br>

&nbsp;&nbsp;&nbsp; [[Rhynchodia]]<br>

&nbsp;&nbsp;&nbsp; [[Chonotrich]]ia<br>

&nbsp;&nbsp;&nbsp; [[Suctoria]] (e.g. ''[[Podophrya]]'')<br>

Class [[Nassophorea]]<br>

Class [[Colpodea]] (e.g. ''[[Colpoda]]'')<br>

Class [[Prostomatea]] (e.g. ''[[Coleps]]'')<br>

Class [[Oligohymenophorea]]<br>

&nbsp;&nbsp;&nbsp; [[Peniculid|Peniculia]] (e.g. ''[[Paramecium]]'')<br>

&nbsp;&nbsp;&nbsp; [[Hymenostome|Hymenostomatia]] (e.g. ''[[Tetrahymena]]'')<br>

&nbsp;&nbsp;&nbsp; [[Scuticociliate|Scuticociliatia]]<br>

&nbsp;&nbsp;&nbsp; [[Peritrich]]ia (e.g. ''[[Vorticella]]'')<br>

&nbsp;&nbsp;&nbsp; [[Astome|Astromatia]]<br>

&nbsp;&nbsp;&nbsp; [[Apostome|Apostomatia]]<br>

Class [[Plagiopylid|Plagiopylea]]

{{Taxobox_end}}

The '''ciliates''' are one of the most important groups of [[protist]]s, common almost everywhere there is water - [[lake]]s, [[pond]]s, [[ocean]]s, and [[soil]]s, with many [[Ectosymbiosis|ecto]]- and [[endosymbiotic]] members, as well as some obligate and opportunistic parasites. Ciliates tend to be large protozoa, a few reaching 2 mm in length, and are some of the most complex in structure. The name ''ciliate'' comes from the presence of hair-like organelles called [[cilium|cilia]], which are identical in structure to [[flagellum|flagella]] but typically shorter and present in much larger numbers. Cilia occur in all members of the group, although the peculiar [[suctoria]] only have them for part of the life-cycle, and are variously used in swimming, crawling, attachment, feeding, and sensation.

{{{icon|[[Image:Information.svg|25px]] }}}Welcome to Wikipedia. Although we invite everyone to contribute constructively to our encyclopedia, at least one of your recent edits{{{{{subst|}}}#if:Bedazzler|, such as the one you made to [[:Bedazzler]],}} was not constructive and has been [[Help:Reverting|reverted]] or removed. Please use [[Wikipedia:Sandbox|the sandbox]] for any test edits you would like to make, and take a look at the [[Wikipedia:Introduction|welcome page]] to learn more about contributing to this encyclopedia. {{{{{subst|}}}#if:{{{2|}}}|{{{2}}}|Thank you.}}<!-- Template:uw-vandalism1 --> [[User:Violentbob|Violentbob]] 06:51, 4 July 2007 (UTC)

Unlike other [[eukaryote]]s, ciliates have two different sorts of [[cell nucleus|nuclei]]: a small, [[diploid]] [[micronucleus]] (reproduction), and a large, [[polyploid]] [[macronucleus]] (general cell regulation). The latter is generated from the micronucleus by amplification of the genome and heavy editing. The high degree of polyploidi allows the cell to sustain an appropriate level of [[transcription (genetics)|transcription]]. Division of the macronucleus does not occur by a [[mitosis|mitotic process]] but segregation of the chromosomes is by a different process, whose mechanism is unknown. This process is by no means perfect, and after about 200 generations the cell shows signs of aging. Periodically the macronuclei must be regenerated from the micronuclei. In most, this occurs during [[sexual reproduction]], which is not usually through [[syngamy]] but through ''conjugation''. Here two cells line up, the micronuclei undergo [[meiosis]], some of the [[haploid]] daughters are exchanged and then fuse to form new micro- and macronuclei.

With a few exceptions, there is a distinct ''[[cytostome]]'' or mouth where ingestion takes place. Food [[vacuole]]s are formed through [[phagocytosis]] and typically follow a particular path through the cell as their contents are digested and broken down via [[lysosomes]] so the substances the vacuole contains are then small enough to [[diffuse]] through the membrane of the food vacuole into the cell. Anything left in the food vacuole by the time it reaches the cytoproct (anus) is discharged via [[exocytosis]]. Most ciliates also have one or more prominent contractile vacuoles, which collect water through pinocytosis and expel it from the cell to maintain osmotic pressure, or in some function to maintain ionic balance. These often have a distinctive star-shape, with each point being a collecting tube.

Most ciliates feed on smaller organisms (heterotrophic), such as [[bacterium|bacteria]] and [[alga]]e, and detritus swept into the mouth by modified oral cilia. These usually include a series of membranelles to the left of the mouth and a paroral membrane to its right, both of which arise from ''polykinetids'', groups of many cilia together with associated structures. This varies considerably, however. Some ciliates are mouthless and feed by absorption, while others are predatory and feed on other protozoa and in particular on other ciliates. This includes the suctoria, which feed through several specialized tentacles.

In some forms there are also body polykinetids, for instance, among the [[spirotrich]]s where they generally form bristles called ''cirri''. More often body cilia are arranged in ''mono-'' and ''dikinetids'', which respectively include one and two kinetosomes (basal bodies), each of which may support a cilium. These are arranged into rows called ''kineties'', which run from the anterior to posterior of the cell. The body and oral kinetids make up the ''infraciliature'', an organization unique to the ciliates and important in their classification, and include various fibrils and [[microtubule]]s involved in coordinating the cilia.

The infraciliature is one of the main component of the cell cortex. Another are the ''alveoli'', small vesicles under the cell membrane that are packed against it to form a [[pellicle]] maintaining the cell's shape, which varies from flexible and contractile to rigid. Numerous [[mitochondrion|mitochondria]] and [[extrusome]]s are also generally present. The presence of alveoli, the structure of the cilia, the form of mitosis and various other details indicate a close relationship between the ciliates, [[Apicomplexa]], and [[dinoflagellate]]s. These superficially dissimilar groups make up the [[alveolate]]s.

[[Category:Protista]][[Category:Ciliates|*]]

[[de:Wimpertierchen]]

[[es:Ciliophora]]

[[fr:Ciliata]]

[[nl:Ciliophora]]

[[nds:Ciliophora]]

[[ja:繊毛虫]]

[[pt:Ciliado]]

[[sv:Ciliater]]