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Stentor (ciliate)
''Stentor'', sometimes called trumpet animalcules, are a genus of filter-feeding, heterotrophic ciliates, representative of the heterotrichs. They are usually horn-shaped, and reach lengths of two millimeters; as such, they are among the largest known extant unicellular organisms. They reproduce asexually through binary fission. Description The body, or cortex, is generally horn-shaped, hence the association with the Greek herald, and the former name "trumpet animalcule". A ring of prominent cilia around the anterior "bell" sweep in food and aid in swimming. Some reach several millimeters in length, making them among the largest single-celled organisms. ''Stentor'' can come in different colors: for example, ''S. coeruleus'' can appear blue due to the presence of stentorin, a natural pigment. As in many freshwater protozoans, ''Stentor'' has a contractile vacuole. Because the concentration of salt inside the cell and in the surrounding freshwater is different, ''Stentor'' must ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stentor Roeselii
''Stentor roeselii'' is a free-living ciliate species of the genus '' Stentor'', in the class Heterotrichea. It is a common and widespread protozoan, found throughout the world in freshwater ponds, lakes, rivers and ditches. Appearance and Characteristics ''S. roeselii'' is found in still or slow-moving bodies of water, where it feeds on bacteria, flagellates, algae, and other ciliates. When feeding, the cell is fixed in place ( sessile), attached by a posterior "holdfast" organelle to a firm surface such as plant stem or submerged detritus. Attached specimens are trumpet-shaped, and very contractile. When swimming freely, cells are compactly ovoid. Fully stretched out specimens are usually between 500 and 1200 micrometres in length, but size is extremely variable. It is a colourless species, with no pigmentation in the cell cortex. The body of the organism is covered with 40-80 longitudinal rows of cilia, and the oral region is encircled by a long spiraling row of speciali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stentor Muelleri
''Stentor muelleri'', also called a trumpet ciliate, is a single-celled eukaryote which feeds on algae Algae ( , ; : alga ) are any of a large and diverse group of photosynthetic, eukaryotic organisms. The name is an informal term for a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from .... It has a horned-shaped body and is usually long (exceptionally up to ) and is found in freshwater bodies of water and sometimes estuaries. ''Stentor muelleri'' is a heterotrich. References Heterotrichea {{ciliate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unicellular Organism
A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell, unlike a multicellular organism that consists of multiple cells. Organisms fall into two general categories: prokaryotic organisms and eukaryotic organisms. All prokaryotes are unicellular and are classified into bacteria and archaea. Many eukaryotes are multicellular, but some are unicellular such as protozoa, unicellular algae, and unicellular fungi. Unicellular organisms are thought to be the oldest form of life, with early protocells possibly emerging 3.8–4.0 billion years ago. Although some prokaryotes live in colonies, they are not specialised cells with differing functions. These organisms live together, and each cell must carry out all life processes to survive. In contrast, even the simplest multicellular organisms have cells that depend on each other to survive. Most multicellular organisms have a unicellular life-cycle stage. Gametes, for example ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterotrich
The heterotrichs are a class of ciliates. They typically have a prominent adoral zone of membranelles circling the mouth, used in locomotion and feeding, and shorter cilia on the rest of the body. Many species are highly contractile, and are typically compressed or conical in form. These include some of the largest protozoa, such as '' Stentor'' and '' Spirostomum'', as well as many brightly pigmented forms, such as certain '' Blepharisma''. Etymology The term ''heterotrich'' derives from the ancient Greek (), meaning "another, different", and , (), meaning 'hair', because of the contrast between the regular somatic ciliation and the one of the oral zone. Ultrastructure A number of ultrastructural details characterize the group. The cilia on the body are in dikinetids, in which either the anterior one or both kinetosomes may be ciliated, and which are associated with fibers composed of overlapping postciliary microtubules, called ''postciliodesmata'' and found only in thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciliate
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 soils. 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 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterotroph
A heterotroph (; ) is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but not producers. Living organisms that are heterotrophic include all animals and fungi, some bacteria and protists, and many parasitic plants. The term heterotroph arose in microbiology in 1946 as part of a classification of microorganisms based on their type of nutrition. The term is now used in many fields, such as ecology in describing the food chain. Heterotrophs may be subdivided according to their energy source. If the heterotroph uses chemical energy, it is a chemoheterotroph (e.g., humans and mushrooms). If it uses light for energy, then it is a photoheterotroph (e.g., green non-sulfur bacteria). Heterotrophs represent one of the two mechanisms of nutrition ( trophic levels), the other being autotrophs (''auto'' = self, ''tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stentor Pyriformis
In Greek mythology, Stentor (Ancient Greek: Στέντωρ; ''gen''.: Στέντορος) was a herald of the Greek forces during the Trojan War. Mythology Stentor is mentioned briefly in Homer's ''Iliad'' in which Hera in the guise of Stentor, whose "voice was as powerful as fifty voices of other men" encourages the Greeks to fight. Elsewhere, Stentor is said to have died after losing a shouting contest with Hermes.Scholia on ''Iliad'' 5.785; Eustathius on Homer, ''Iliad'' 607.29 Stentor's story is the origin of the term "stentorian", meaning loud-voiced, for which he was famous. Aristotle uses the concept in his ''Politics'' Book 7, Chapter IV saying, "For who can be the general of such a vast multitude, or who the herald, unless he have the voice of a Stentor?" See also * List of Trojan War characters Notes References * Homer Homer (; grc, Ὅμηρος , ''Hómēros'') (born ) was a Greek poet who is credited as the author of the '' Iliad'' and the '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
