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47-633: See text Paramecium ( / ˌ p ær ə ˈ m iː s ( i ) ə m / PARR -ə- MEE -s(ee-)əm , /- s i ə m / -⁠see-əm , plural "paramecia" only when used as a vernacular name ) is a genus of eukaryotic , unicellular ciliates , widespread in freshwater , brackish , and marine environments. Paramecia are often abundant in stagnant basins and ponds. Because some species are readily cultivated and easily induced to conjugate and divide, they have been widely used in classrooms and laboratories to study biological processes . Paramecium species are commonly studied as model organisms of

94-638: A Paramecium species was published anonymously in Philosophical Transactions of the Royal Society in 1703. In 1718, the French mathematics teacher and microscopist Louis Joblot published a description and illustration of a microscopic poisson (fish), which he discovered in an infusion of oak bark in water. Joblot gave this creature the name "Chausson" , or "slipper", and the phrase "slipper animalcule" remained in use as

141-774: A flora of his homeland Sweden, Flora Svecica (1745), and in this, he recorded the Swedish common names, region by region, as well as the scientific names. The Swedish common names were all binomials (e.g. plant no. 84 Råg-losta and plant no. 85 Ren-losta); the vernacular binomial system thus preceded his scientific binomial system. Linnaean authority William T. Stearn said: By the introduction of his binomial system of nomenclature, Linnaeus gave plants and animals an essentially Latin nomenclature like vernacular nomenclature in style but linked to published, and hence relatively stable and verifiable, scientific concepts and thus suitable for international use. The geographic range over which

188-469: A chemical, does not follow the current systematic naming convention, such as acetone , systematically 2-propanone , while a vernacular name describes one used in a lab, trade or industry that does not unambiguously describe a single chemical, such as copper sulfate , which may refer to either copper(I) sulfate or copper(II) sulfate. Sometimes common names are created by authorities on one particular subject, in an attempt to make it possible for members of

235-524: A colloquial epithet for Paramecium , throughout the 18th and 19th centuries. The name " Paramecium " – constructed from the Greek παραμήκης ( paramēkēs , "oblong") – was coined in 1752 by the English microscopist John Hill , who applied the name generally to " Animalcules which have no visible limbs or tails, and are of an irregularly oblong figure." In 1773, O. F. Müller , the first researcher to place

282-399: A copy of the micronucleus and the macronucleus. Fission may occur spontaneously, in the course of the vegetative cell cycle . Under certain conditions, it may be preceded by self-fertilization ( autogamy ), or it may immediately follow conjugation , in which Paramecium of compatible mating types fuse temporarily and exchange genetic material. In ciliates such as Paramecium , conjugation

329-485: A particularly common name is used varies; some common names have a very local application, while others are virtually universal within a particular language. Some such names even apply across ranges of languages; the word for cat , for instance, is easily recognizable in most Germanic and many Romance languages . Many vernacular names, however, are restricted to a single country and colloquial names to local districts. Some languages also have more than one common name for

376-433: A possible instance of cell memory, or epigenetic learning in organisms with no nervous system . Like all ciliates, Paramecium have a dual nuclear apparatus , consisting of a polyploid macronucleus , and one or more diploid micronuclei . The macronucleus controls non-reproductive cell functions, expressing the genes needed for daily functioning. The micronucleus is the generative, or germline nucleus, containing

423-416: A single cilium projects. Between the alveolar sacs of the pellicle, most species of Paramecium have closely spaced spindle-shaped trichocysts , explosive organelles that discharge thin, non-toxic filaments, often used for defensive purposes. Typically, an anal pore (cytoproct) is located on the ventral surface, in the posterior half of the cell. In all species, there is a deep oral groove running from

470-437: A slow "recovery stroke," during which the cilium curls loosely to one side and sweeps forward in a counter-clockwise fashion. The densely arrayed cilia move in a coordinated fashion, with waves of activity moving across the "ciliary carpet," creating an effect sometimes likened to that of the wind blowing across a field of grain. The Paramecium spirals through the water as it progresses. When it happens to encounter an obstacle,

517-521: Is a sexual phenomenon that results in genetic recombination and nuclear reorganization within the cell. During conjugation, two Paramecium of a compatible mating type come together and form a bridge between their cytoplasms . Their respective micronuclei undergo meiosis , and haploid micronuclei are exchanged over the bridge. Following conjugation, the cells separate. The old macronuclei are destroyed, and both post-conjugants form new macronuclei, by amplification of DNA in their micronuclei. Conjugation

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564-484: Is followed by one or more "exconjugant divisions." In Paramecium caudatum , the stages of conjugation are as follows (see diagram at right): In the asexual fission phase of growth, during which cell divisions occur by mitosis rather than meiosis, clonal aging occurs leading to a gradual loss of vitality. In some species, such as the well studied Paramecium tetraurelia , the asexual line of clonally aging Paramecium loses vitality and expires after about 200 fissions if

611-461: Is in these remarks from a book on marine fish: In scientific binomial nomenclature, names commonly are derived from classical or modern Latin or Greek or Latinised forms of vernacular words or coinages; such names generally are difficult for laymen to learn, remember, and pronounce and so, in such books as field guides, biologists commonly publish lists of coined common names. Many examples of such common names simply are attempts to translate

658-469: Is nevertheless close to the maximum theoretical efficiency that can be achieved by an organism equipped with cilia as short as those of the members of Paramecium. Paramecium feed on microorganisms such as bacteria, algae, and yeasts . To gather food, the Paramecium makes movements with cilia to sweep prey organisms, along with some water, through the oral groove (vestibulum, or vestibule), and into

705-604: Is the Cape dikkop (or "gewone dikkop", not to mention the presumably much older Zulu name "umBangaqhwa"); Burhinus vermiculatus is the "water dikkop". The thick joints in question are not even, in fact, the birds' knees, but the intertarsal joints —in lay terms the ankles. Furthermore, not all species in the genus have "thick knees", so the thickness of the "knees" of some species is not of clearly descriptive significance. The family Burhinidae has members that have various common names even in English, including " stone curlews ", so

752-519: The ICZN has formal rules for biological nomenclature and convenes periodic international meetings to further that purpose. The form of scientific names for organisms, called binomial nomenclature , is superficially similar to the noun-adjective form of vernacular names or common names which were used by non-modern cultures. A collective name such as owl was made more precise by the addition of an adjective such as screech . Linnaeus himself published

799-404: The amino acid glutamic acid . The question of whether Paramecium exhibit learning has been the object of a great deal of experimentation, yielding equivocal results. However, a study published in 2006 seems to show that Paramecium caudatum may be trained, through the application of a 6.5 volt electric current , to discriminate between brightness levels. This experiment has been cited as

846-462: The anterior of the cell to its midpoint. This is lined with inconspicuous cilia which beat continuously, drawing food into the cell. Paramecium are primarily heterotrophic , feeding on bacteria and other small organisms. A few species are mixotrophs , deriving some nutrients from endosymbiotic algae ( chlorella ) carried in the cytoplasm of the cell. Osmoregulation is carried out by contractile vacuoles , which actively expel water from

893-496: The "effective stroke" of its cilia is reversed and the organism swims backward for a brief time, before resuming its forward progress. This is called the avoidance reaction . If it runs into the solid object again, it repeats this process, until it can get past the object. It has been calculated that a Paramecium expends more than half of its energy in propelling itself through the water. This ciliary method of locomotion has been found to be less than 1% efficient. This low percentage

940-710: The SSAR switched to an online version with a searchable database. Standardized names for the amphibians and reptiles of Mexico in Spanish and English were first published in 1994, with a revised and updated list published in 2008. A set of guidelines for the creation of English names for birds was published in The Auk in 1978. It gave rise to Birds of the World: Recommended English Names and its Spanish and French companions. The Academy of

987-534: The Secretariat for the AFNC. SSA is an accredited Standards Australia (Australia's peak non-government standards development organisation) Standards Development The Entomological Society of America maintains a database of official common names of insects, and proposals for new entries must be submitted and reviewed by a formal committee before being added to the listing. Efforts to standardize English names for

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1034-423: The ability to kill other strains of Paramecium that lack kappa particles. The genome of the species Paramecium tetraurelia has been sequenced, providing evidence for three whole- genome duplications . In some ciliates, like Stylonychia and Paramecium , only UGA is decoded as a stop codon , while UAG and UAA are reassigned as sense codons (that is, codons that code for standard amino acids), coding for

1081-505: The amphibians and reptiles of North America (north of Mexico) began in the mid-1950s. The dynamic nature of taxonomy necessitates periodical updates and changes in the nomenclature of both scientific and common names. The Society for the Study of Amphibians and Reptiles (SSAR) published an updated list in 1978, largely following the previous established examples, and subsequently published eight revised editions ending in 2017. More recently

1128-515: The author introduced into it so many new English names, that are to be found in no dictionary, and that do not preclude the necessity of learning with what Latin names they are synonymous. A tolerable idea may be given of the danger of too great a multiplicity of vulgar names, by imagining what geography would be, or, for instance, the Post-office administration, supposing every town had a totally different name in every language. Various bodies and

1175-493: The authors of many technical and semi-technical books do not simply adapt existing common names for various organisms; they try to coin (and put into common use) comprehensive, useful, authoritative, and standardised lists of new names. The purpose typically is: Other attempts to reconcile differences between widely separated regions, traditions, and languages, by arbitrarily imposing nomenclature, often reflect narrow perspectives and have unfortunate outcomes. For example, members of

1222-405: The cell body by the streaming movement of the cell contents, a process called cyclosis or cytoplasmic streaming . As a food vacuole moves along, enzymes from the cytoplasm enter it, to digest the contents. As enzymatic digestion proceeds, the vacuole contents become more acidic. Within five minutes of a vacuole's formation, the pH of its contents drops from 7 to 3. As digested nutrients pass into

1269-406: The cell is enclosed by a stiff but elastic structure called the pellicle . The pellicle consists of an outer cell membrane (plasma membrane), a layer of flattened membrane-bound sacs called alveoli , and an inner membrane called the epiplasm . The pellicle is not smooth, but textured with hexagonal or rectangular depressions. Each of these polygons is perforated by a central aperture through which

1316-412: The cell to compensate for fluid absorbed by osmosis from its surroundings. The number of contractile vacuoles varies depending on the species. A Paramecium propels itself by whip-like movements of the cilia, which are arranged in tightly spaced rows around the outside of the body. The beat of each cilium has two phases: a fast "effective stroke," during which the cilium is relatively stiff, followed by

1363-424: The cell. The food passes from the cilia-lined oral groove into a narrower structure known as the buccal cavity (gullet). From there, food particles pass through a small opening called the cytostome , or cell mouth, and move into the interior of the cell. As food enters the cell, it is gathered into food vacuoles , which are periodically closed off and released into the cytoplasm , where they begin circulating through

1410-401: The cells fail to undergo autogamy or conjugation. The basis for clonal aging was clarified by transplantation experiments of Aufderheide in 1986. When macronuclei of clonally young Paramecium were injected into Paramecium of standard clonal age, the lifespan (clonal fissions) of the recipient was prolonged. In contrast, transfer of cytoplasm from clonally young Paramecium did not prolong

1457-408: The choice of the name "thick-knees" is not easy to defend but is a clear illustration of the hazards of the facile coinage of terminology. For collective nouns for various subjects, see a list of collective nouns (e.g. a flock of sheep, pack of wolves). Some organizations have created official lists of common names, or guidelines for creating common names, hoping to standardize

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1504-474: The ciliate group and have been characterized as the " white rats " of the phylum Ciliophora . Paramecium were among the first ciliates to be observed by microscopists , in the late 17th century. They were most likely known to the Dutch pioneer of protozoology , Antonie van Leeuwenhoek , and were clearly described by his contemporary Christiaan Huygens in a letter from 1678. The earliest known illustration of

1551-588: The cytoplasm, the vacuole shrinks. When the fully digested vacuole reaches the anal pore, it ruptures, expelling its waste contents outside the cell. Some species of Paramecium form mutualistic relationships with other organisms. Paramecium bursaria and Paramecium chlorelligerum harbour endosymbiotic green algae, from which they derive nutrients and a degree of protection from predators such as Didinium nasutum . Numerous bacterial endosymbionts have been identified in species of Paramecium . Some intracellular bacteria, known as kappa particles , give Paramecium

1598-464: The general public (including such interested parties as fishermen, farmers, etc.) to be able to refer to one particular species of organism without needing to be able to memorise or pronounce the scientific name. Creating an "official" list of common names can also be an attempt to standardize the use of common names, which can sometimes vary a great deal between one part of a country and another, as well as between one country and another country, even where

1645-420: The generation of any new genetic variation in P. tetraurelia . This observation suggests that the underlying molecular mechanism of meiosis provides a fitness advantage regardless of any concomitant effect of sex on genetic diversity . Paramecium aurelia species complex: Other species: Common name In chemistry , IUPAC defines a common name as one that, although it unambiguously defines

1692-436: The genetic descendants are rejuvenated, and are able to have many more mitotic binary fission divisions. During conjugation or automixis , the micronuclei of the cell(s) undergo meiosis, the old macronucleus disintegrates, and a new macronucleus is formed by replication of the micronuclear DNA that had recently undergone meiosis. There is apparently little, if any, DNA damage in the new macronucleus. These findings further support

1739-470: The genetic material that is passed along from one generation to the next. Paramecium reproduction is asexual , by binary fission , which has been characterized as "the sole mode of reproduction in ciliates" ( conjugation being a sexual phenomenon, not directly resulting in increase of numbers). During fission, the macronucleus splits by a type of amitosis , and the micronuclei undergo mitosis . The cell then divides transversally, and each new cell obtains

1786-522: The genus Burhinus occur in Australia, Southern Africa, Eurasia, and South America. A recent trend in field manuals and bird lists is to use the name " thick-knee " for members of the genus. This, in spite of the fact that the majority of the species occur in non-English-speaking regions and have various common names, not always English. For example, "Dikkop" is the centuries-old South African vernacular name for their two local species: Burhinus capensis

1833-578: The genus within the Linnaean system of taxonomy , adopted the name Paramecium but changed the spelling to Paramæcium. In 1783, Johann Hermann changed the spelling once more, to Paramœcium . C. G. Ehrenberg , in a major study of the infusoria published in 1838, restored Hill's original spelling for the name, and most researchers have followed his lead. Species of Paramecium range in size from 0.06 mm to 0.3 mm in length. Cells are typically ovoid, elongate, or foot- or cigar-shaped. The body of

1880-692: The idea that clonal aging is due, in large part, to a progressive accumulation of DNA damage; and that rejuvenation is due to the repair of this damage in the micronucleus during meiosis. Meiosis appears to be an adaptation for DNA repair and rejuvenation in P. tetraurelia . In P. tetraurelia , CtlP protein is a key factor needed for the completion of meiosis during sexual reproduction and recovery of viable sexual progeny. The CtlP and Mre11 nuclease complex are essential for accurate processing and repair of double-strand breaks during homologous recombination. The adaptive benefit of meiosis and self-fertilization in response to starvation appears to be independent of

1927-712: The lifespan of the recipient. These experiments indicated that the macronucleus, rather than the cytoplasm, is responsible for clonal aging. Other experiments by Smith-Sonneborn, Holmes and Holmes, and Gilley and Blackburn demonstrated that, during clonal aging, DNA damage increases dramatically. Thus, DNA damage in the macronucleus appears to be the cause of aging in P. tetraurelia . In this single-celled protist , aging appears to proceed as it does in multicellular eukaryotes , as described in DNA damage theory of aging . When clonally aged P. tetraurelia are stimulated to undergo meiosis in association with either conjugation or automixis ,

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1974-711: The modern (now binding) International Code of Nomenclature for algae, fungi, and plants contains the following: Art. 68. Every friend of science ought to be opposed to the introduction into a modern language of names of plants that are not already there unless they are derived from a Latin botanical name that has undergone but a slight alteration. ... ought the fabrication of names termed vulgar names, totally different from Latin ones, to be proscribed. The public to whom they are addressed derives no advantage from them because they are novelties. Lindley's work, The Vegetable Kingdom, would have been better relished in England had not

2021-488: The same animal. For example, in Irish, there are many terms that are considered outdated but still well-known for their somewhat humorous and poetic descriptions of animals. w/ literal translations of the poetic terms Common names are used in the writings of both professionals and laymen . Lay people sometimes object to the use of scientific names over common names, but the use of scientific names can be defended, as it

2068-576: The same language is spoken in both places. A common name intrinsically plays a part in a classification of objects, typically an incomplete and informal classification, in which some names are degenerate examples in that they are unique and lack reference to any other name, as is the case with say, ginkgo , okapi , and ratel . Folk taxonomy , which is a classification of objects using common names, has no formal rules and need not be consistent or logical in its assignment of names, so that say, not all flies are called flies (for example Braulidae ,

2115-402: The scientific name into English or some other vernacular. Such translation may be confusing in itself, or confusingly inaccurate, for example, gratiosus does not mean "gracile" and gracilis does not mean "graceful". The practice of coining common names has long been discouraged; de Candolle's Laws of Botanical Nomenclature , 1868, the non-binding recommendations that form the basis of

2162-407: The so-called "bee lice") and not every animal called a fly is indeed a fly (such as dragonflies and mayflies ). In contrast, scientific or biological nomenclature is a global system that attempts to denote particular organisms or taxa uniquely and definitively , on the assumption that such organisms or taxa are well-defined and generally also have well-defined interrelationships; accordingly

2209-832: The use of common names. For example, the Australian Fish Names List or AFNS was compiled through a process involving work by taxonomic and seafood industry experts, drafted using the CAAB (Codes for Australian Aquatic Biota) taxon management system of the CSIRO , and including input through public and industry consultations by the Australian Fish Names Committee (AFNC). The AFNS has been an official Australian Standard since July 2007 and has existed in draft form (The Australian Fish Names List) since 2001. Seafood Services Australia (SSA) serve as

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