Ciliophora
Sign in to saveThe ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different undulating pattern than flagella. Cilia occur in all members of the group (although the peculiar Suctoria only have them for part of their life cycle) and are variously used in swimming, crawling, attachment, feeding, and sensation.
AI overview
Ciliophora are single-celled organisms covered in tiny, hair-like structures called cilia that they use for movement, feeding, and sensing their environment. These microscopic creatures are found widely in nature and are important members of aquatic ecosystems, serving as both predators and prey in food chains.
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Species
ciliates
Phylum
- PhylumCiliophora
Habitatmarine, brackish, freshwater
纤毛虫是纤毛虫门（學名：Ciliophora）生物的通称，是一类较复杂的原生动物，主要特点是以纤毛作为运动器，细胞核一般分化出大核（营养）、小核（生殖）、摄食胞器等，无性生殖为横二分裂，有性生殖为接合生殖，生活在淡水或海水中，也有寄生的。[1][2]代表生物有草履虫，小瓜虫等。 纤毛虫在分类上比较复杂，尚无统一的定论。按传统的分类，原生动物作为动物界中的一个门，纤毛虫为其中的“纤毛纲”（Ciliata），有时也将其列为原生动物门的纤毛亚门，或将原生动物看作动物界的一个亚界，纤毛虫划为一个门——纤毛门。[2]按照汤玛斯·卡弗利尔-史密斯提出的分类系统则属于囊泡藻界的“纤毛虫门”（Ciliophora）。 目录 1 细胞结构 1.1 细胞核 1.2 细胞质 2 繁殖 3 分类 3.1 Postciliodesmatophora亚门 3.2 Intramacronucleata亚门 3.3 未归类 4 参考资料 细胞结构 Cell 纤毛虫细胞结构: 1-收缩泡, 2-食物泡, 3-大核, 4-小核, 5-胞肛, 6-胞咽, 7-胞口, 8-纤毛. 细胞核 与其他大部分真核生物不同,纤毛虫有两种大小不同的核，一种是二倍体的小核，负责基因重组；另一种是多倍体的大核，负责一般细胞调控。 细胞质 食物通过胞吞作用，经过胞口胞咽进入食物泡，通过溶酶体分解使其颗粒变小，能通过膜扩散入细胞质中，残留在食物泡中的物质在胞肛处以胞吐作用排出。 大多数纤毛虫也具有一个或多个突出的收缩泡，收集和排出水以维持细胞内渗透压，以及维持离子平衡。在某些属中（如草履虫），收缩泡有着明显的星状造型，每个星芒都是一个收集管。 繁殖 纤毛虫都可以进行无性繁殖和有性繁殖。无性繁殖二分裂方式进行，小核发生有丝分裂,大核伸长并分为两半，然后该细胞一分为二。两个新细胞各获得一个大核和一个小核。 与此相反，有性繁殖涉及两个不同交配型（类似性别，但也存在两个以上的交配型）个体之间的结合和遗传物质的交换，这往往发生在食物短缺的时候。 分类 “纤毛虫门”分为两个亚门[3]： Postciliodesmatophora亚门 核残迹纲（英语：Karyorelictea） Karyorelictea Corliss，1974 异毛纲（英语：Heterotrich） Heterotrichea Stein，1859 Intramacronucleata亚门 Oxytricha trifallax 旋毛纲（英语：Spirotrich） Spirotrichea Butschli，1889[4] 环毛亚纲（英语：Choreotrich） Small & Lynn 1985（如丁丁蟲 Tintinnidium） 寡毛亚纲（英语：Oligotrichia） Oligotrichia (e.g. Halteria)[5] 排毛
via
Research
15,652 papersArticle
20 sectionsContents
- Cell structure
- Nuclei
- Cytoplasm
- Specialized structures in ciliates
- Feeding
- Reproduction and sexual phenomena
- Reproduction
- Conjugation
- DNA rearrangements (gene scrambling)
- Aging
- Fossil record
- Phylogeny
- Classification
- Subphylum Postciliodesmatophora
- Subphylum Intramacronucleata
- Other
- Pathogenicity
- References
- Further reading
- External links
The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different undulating pattern than flagella. Cilia occur in all members of the group (although the peculiar Suctoria only have them for part of their life cycle) and are variously used in swimming, crawling, attachment, feeding, and sensation.
Ciliates are an important group of protists, common almost anywhere there is water—in lakes, ponds, oceans, rivers, and wet soils, including anoxic (oxygen-depleted) habitats. About 4,500 unique free-living species have been described, and the potential number of extant species is estimated at 27,000–40,000. Included in this number are many ectosymbiotic and endosymbiotic species, as well as some obligate and opportunistic parasites. Ciliate species range in size from as little as 10 μm in some colpodeans to as much as 4 mm in length in some geleiids, and include some of the most morphologically complex protozoans.