Daphnia pulex is the most common species of the group of organisms known as water fleas. Their common name was given because of their general appearance and jerky swimming motions which resembles that of the land flea. They are, in reality, a type of small crustacean and are generally 0.2-3.0 mm long. Their bodies are not distinctly segmented, but an important feature of their anatomy is the carapace, a folded shell-like structure which covers the animal and opens both ventrally and posteriorly. Studying the anatomy of this organism is made easier by the fact that most of its outer covering is clear, showing most of the internal organs at work, including the heart. The head of the organism contains both a darkly colored compound eye and numerous antennae used for feeling and swimming. Many Daphnia, including D. pulex and D. magna have a specialized light-sensing organ similiar to a tiny eye called an ocellus. Located posteriorly at the junction of the head are small, hard to see mouthparts. They mainly consist of the mandibles which are in constant motion and used by the organism to crush and grind its food. In a live specimen food particles can be seen passing through the intestine which terminates at the anus located on the postabdomen. The postabdomen is the most posterior part of the body and terminates itself in two hooklike cuticular claws used by the organism to clear debris out of the carapace. The fine teeth located on these claws are often used for species identification. The central portion of the body is the thorax and contains four to six pairs of flattened legs covered in setae. Daphnia males are generally smaller than females but have longer antennules and a modified postabdomen. Daphnia females posses a brood chamber located between the body wall and dorsal surface of the carapace used to carry their eggs.
Other Physical Features: ectothermic ; bilateral symmetry
Daphnia can be found in almost any permanent body of water, even in rain-filled tire ruts or several meters from the ground, growing in tree moss in a rainforest. They are mainly freshwater and the highest concentrations of Daphnia populations are found in the vegetation in most lakes and ponds. They are often the most abundant organism in a body of water. They live as plankton in the open water of lakes, or live either attached to vegetation or near the bottom of the body of water.
While very prolific in most freshwater bodies, Daphnia are too small and weak to live in a strong current, which they are unable to swim against. They live in a water column and are light enough to stay suspended by using their legs and antennae for movement. They live mainly in the upper portion of this water column near the algae-rich surface of the water, but they will often move up or down the column depending on seasons or predators in a process called diel vertical migration. They are often forced to expend a large amount of energy moving towards a lower depth during the day in order to avoid predators and coming towards the surface to eat at night. Their location is also controlled by seasonal variation in their phytoplankton food supply.
Aquatic Biomes: benthic ; lakes and ponds; rivers and streams; coastal
Daphnia pulex is the most common species of the water flea, an organism which can be found in almost every permanent, eutrophic (nutrient-rich) water body. A few species are marine, but generally Daphnia, including Daphnia pulex, are freshwater organisms.
Biogeographic Regions: nearctic (Native ); palearctic (Native ); oriental (Native ); ethiopian (Native ); neotropical (Native ); australian (Native )
Daphnia are oftened used to clear fish tanks of algae "bloom" because of their diet of bacteria, fine detritus, and very small algae particles. They are filter feeders meaning they do not usually actively seek food; they merely create a constant movement of water using their thoraic legs through their carapace where they are able to filter out any food particles with the setae and direct these towards the mouth. If a mass of food becomes entangled in the mandibles it is cleared by the spines located on the first legs and then kicked out of the carapace by the postabdomen. Not all algae is eaten by Daphnia, such as blue-green algae which has too tough of an outer cell wall and filamentous green algae which can be detrimental to the organism's health. While most species of Daphnia, including D. pulex, are herbivorous or detritivorous (feeding on phytoplankton), a few are carnivorous and prey on other water fleas.
Although Daphnia are not used by humans as a food source directly, they are involved in many of the foodchains necessary to sustain fish that we consume or use commercially such as sticklebacks, minnows and young Sockeye salmon. They also are a primary food supply for those animals that trout and many other popular fish depend on. Also, almost any freshwater ecosystem is dependent on Daphnia's ability to convert phytoplankton and decaying matter into a more usable form.
Daphnia are also very frequently used by scientists for experimentation. They are small, cheap, and very easy to keep alive in a laboratory environment. Their almost transparent shell makes their internal functions easier to study and they are very susceptible to changes in temperature, food supplies, or dissolved oxygen content in their environment. Aquarium owners often use Daphnia both as a food source for their fish and to clear the water of debris.
In general, Daphnia are beneficial to an aquatic environment, but they will occasionally limit the population size of other organisms as they compete for food and oxygen. Although they are often used in fish tanks to clear the water of algal bloom, fish are not able to be kept in the same tank with a high number of Daphnia because of a limit on the oxygen availability.
Daphnia are extremely widespread and common throughout the world. However, they are often used as a food source for aquarium fish and although some of these are raised specifically for this purpose, many are harvested from lakes or ponds. While this practice is unlikely to erradicate all Daphnia species, it could damage some rare populations with a limited range.
Genetic variation is often very hard to moniter in Daphnia due to their unusual reproductive method of parthenogenesis. Parthenogenic males are difficult to find at certain times, and hybrids will result in a problem as they are often unable to breed or create viable offspring. Daphnia, however, still have a very high degree of genetic variation even within a single population or species. They are able to change their size and shape in response to their environment and this ability makes it harder to classify these organisms into specific groups. Often there seems to be more variation within a species than between them.
Daphnia pulex reproduces both sexually and asexually in a process called parthenogenesis, where male gametes are unnecessary. Parthenogenesis occurs mainly in the summer, so that during summer an entire population of Daphnia pulex will consist almost completely of females. This process begins in the female, which then molt the carapace to increase their size and develope anywhere from two to twenty eggs in their brood chamber. Even without fertilization from a male, these eggs will develope into immature females which are released after the next molting stage. The young that are produced in this way are more precocial or well-developed than in the process of producing altricial fertilized eggs. This stage of reproduction is most used for a rapid increase in Daphnia growth but requires more favorable conditions.
The sexual stage of Daphnia reproduction occurs mainly in the winter during less favorable conditions caused by overcrowding, accumulation of wastes, lower food availability, and lower temperatures. First, some of the eggs that were produced by parthenogenesis hatch into males instead of females. These males then copulate with the females to form fertilized eggs which are then kept in the female's brood chamber. After the female's next molt she releases these eggs which have the ability to overwinter. They can resist freezing and drying while encased in a purselike ephippium that protects the egg as it rests in the sediment at the bottom of the water body until spring. These eggs remain in this stage of arrested developement, lasting up to twenty years, until the conditions become more favorable for hatching.
Daphnia usually live about ten to thirty days and can live up to one hundred days if their environment is free of predators. An individual will generally have ten to twenty instars, or periods of growth, during their lifetime.
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual ; asexual ; fertilization (Internal ); oviparous
Tip: Bugumayaqlılar (Artropoda)
Sinif: Xərçənglər (Crustacea)
Y/sinif: Ayağıqəlsəməlilər ( Brachiopoda )
Dəstə: Yarpaqayaqlılar (Phillopoda)
Y/dəstə: Şəaxəbığcıqlı xərçənglər (Cladocera)
Fəsilə: Dafnidkimilər (Daphnidae)
Cins: Daphnia O.F. Müller, 1785
Növ: Daphnia pulex (De Geer), 1778
Dişi fərdin uzunluğu 1,4-4,0, erkəyinki isə 0,9-1,5 mm -dir. Dişi fərdin çanağı oval formada olub, yan tilləri yoxdur, quyruq iynəsi qismən uzundur. Çanağın arxa hissəsi və quyruq iynəsi tikanlı çıxıntılarla örtülmü.dür. Baş qıs lateral til ilə təchiz olunmuşdur. Baş zirehi çanağa söykənir və çıxıq əmələ gətirir. Rostrum uzanmış və itidir. Ön antenaları qısa olub, rostrumun qurtaracağına çatır. Uzanmış və yuxarı kənarı azacıq qabarmış postabdomenin üzərində 12-18 ədədə qədər dişçik yerləşir. Abdomen caynağının əyilmiş kənarı boyunca 12-14 ədəd nazik tükcüklərdən ibarət olan bazal daraq yerləşir.Erkək fərd dişidən çanağın rombvari və bel kənarının düz olması ilə fərqlənir. Rostrum çox qısa və kütdür. Ön antennaların oturacaqları uzun və azacıq əyilmişdir. Onun qurtaracağındaestetacklar və qamçı yerləşir. Qamçı 2 buğumludur. Abdomen çıxıntısi barmaqvari olub, səthini çərgəyə düzülmüş tükcüklər örtür.
Bu növə dünyanın bütün sularında rast gəlinir. Naxçıvan MR-nın Adilağa, Xıncov, Qanlıgöl, Batabat, Salvardı, Dəstəgöl, Qaraxanbəyli göllərində, Uzunoba su anbarında, Şahbuz və Biçənək yaxınlığında olan su tutarlarında, Kiçik qafqazın sarımsaqlı, Cifligöl, Ayıtələsi və Göy-göl göllərində, Qax rayonunun Muran gölündə, İsmayıllı rayonundakı Qaragöldə, Şamaxı, Göyçay, Astara, Lənkəran və Masallı rayonlarının şirin sularında geniş yayılmışdır.
Evritop növ olub, şimal və orta en dairələrində yerləşən kiçik su hövzələrində, cənubda isə göl və su anbarlarının peligial hissəsində yaşayır. Yumurtalarının sayı 50-yə çatır. Azərbaycan ərazisində bu növün ən yaxşı inkişafı Göy-göldə qeydə alınmışdır. Növün 5 yarımnövü vardır ki, onlardan 3 yarımnöv (D. pulex middendorfiana, D.pulex pulicaria, D.pulex schölderi) Azərbaycanın su hövzələrində qeydə alınır.[1]
Bu məqalə qaralama halındadır. Məqaləni redaktə edərək Vikipediya kömək edə bilərsiniz.Hrotnatka obecná (Daphnia pulex) je korýš patřící do řádu perlooček.
Hrotnatka měří asi 0,5-1 mm. Má okrouhlé tělo, z boku zploštělé s nápadným druhým párem tykadel (první pár je velmi malý) a výrazným složeným okem. Kromě hlavy je tělo kryto chitinovým krunýřem. Tykadla druhého páru jsou na koncích rozvětvená a opatřená veslovacími brvami. Pomocí nich se hrotnatka pohybuje. Krátké nožky na hrudi mají lupínkovité žábry. Rytmickými pohyby nožek je voda s mikroskopickou potravou (planktonem) přiváděna k ústům. Při pozorování v mikroskopu můžeme v průhledném těle vidět srdce, zažívací trubici a u samice i vajíčka. V letním období se mohou líhnout jedinci i z neoplozených vajíček.
Der Gemeine Wasserfloh (Daphnia pulex) ist eine Art aus der Gattung der Daphnien (Daphnia).
Die Art ist breit und kräftig geformt. Sie ist grünlich, gelblich oder rötlich gefärbt und meist nur wenig durchsichtig. Die Weibchen werden 3 bis 4 Millimeter groß, die Männchen 1 bis 1,5 Millimeter. Die Männchen sind durch die langen ersten Antennen und den auffälligen Haken am ersten Beinpaar erkennbar. Ein Naupliusauge ist vorhanden. Meistens ist die Schale ausgezogen zu einem vierkantigen Schalenstachel. Der Kopfpanzer ist nach hinten in einen sich zwischen die Schalenteile schiebenden Zipfel ausgezogen. Die „Riechstäbchen“ der ersten Antenne reichen nicht bis zum Rostrum. Die zweiten Antennen weisen je neun gefiederte Schwimmborsten auf. Das Auge ist groß und besteht aus 22 Einzelaugen. Der Vorderdarm besitzt zwei gebogene, grünliche Leberhörnchen. An den Endkrallen des Postabdomens (Afterkrallen) befinden sich zwei aus Borsten bestehende Kämme.
Daphnia pulex kommt in kleinen, seichten Tümpeln und Teichen sowie der Uferzone größerer Gewässer vor. Sie ist sehr häufig und tritt oft massenhaft auf.
Das Erbgut des Gemeinen Wasserflohs ist entschlüsselt. Es enthält 30.907 Gene bei nur 200 Millionen Basenpaaren und damit etwa die Hälfte mehr als das des Menschen (20.000 bis 23.000 Gene, aber bei 3 Milliarden Basenpaaren), die bislang höchste bekannte Zahl im Tierreich. Es wird angenommen, dass das eine Voraussetzung für die gute Anpassungsfähigkeit der Art an wechselnde Umweltbedingungen ist. 36 Prozent der entdeckten Erbanlagen sind von keiner anderen Art bekannt.[1]
Der Gemeine Wasserfloh (Daphnia pulex) ist eine Art aus der Gattung der Daphnien (Daphnia).
Daphnia pulex is the most common species of water flea.[3] It has a cosmopolitan distribution: the species is found throughout the Americas, Europe, and Australia.[4] It is a model species, and was the first crustacean to have its genome sequenced.
D. pulex is an arthropod whose body segments are difficult to distinguish. It can only be recognised by its appendages (only ever one pair per segment), and by studying its internal anatomy.[5] The head is distinct and is made up of six segments, which are fused together even as an embryo. It bears the mouthparts, and two pairs of antennae, the second pair of which is enlarged into powerful organs used for swimming.[5] No clear division is seen between the thorax and abdomen, which collectively bear five pairs of appendages.[5] The shell surrounding the animal extends posteriorly into a spine.[6] Like most other Daphnia species, D. pulex reproduces by cyclical parthenogenesis, alternating between sexual and asexual reproduction.[7]
D. pulex occurs in a wide range of aquatic habitats, although it is most closely associated with small, shaded pools.[8] In oligotrophic lakes, D. pulex has little pigmentation, while it may become bright red in hypereutrophic waters, due to the production of haemoglobin.[8]
Daphnia species are prey for a variety of both vertebrate and invertebrate predators. The role of predation on D. pulex population ecology is extensively studied, and has been shown to be a major axis of variation in shaping population dynamics[9] and landscape-level distribution.[10] In addition to the direct population ecological effects of predation, the process contributes to phenotypic evolution in contrasting ways; larger D. pulex individuals are more visible to vertebrate predators, but invertebrate predators are unable to handle larger ones. As a result, larger water fleas tend to be found with invertebrate predators, while smaller size is associated with vertebrate predators.
Similar to some other Daphnia species, the morphology of D. pulex exhibits a plastic response to the presence of predators. Phantom midge larvae (Chaoborus) release kairomones – chemical cues – that induce the development of small, jagged protrusions on the head, known as "neck teeth",[11] which increase survivorship in the presence of the invertebrate predator, but at a cost – longer development time, for example – when those predators are not present.[12]
D. pulex ecology is shaped by nutrient availability and balance, which affects traits that mediate intra- and interspecific interactions. Because nutrients are required for an array of biological processes – for example, amino acid synthesis – the environmental availability of these nutrients regulates downstream organismal characteristics.[13] Low nutrient availability reduces both body size and growth rate, which, as noted above, regulates Daphnia relationships to predators. D. pulex in particular has been an important model species for investigating ecological stoichiometry, demonstrating that pond shading by trees increases nutrient concentrations relative to carbon in algae, which increases D. pulex body size, and therefore competitive ability and susceptibility to predation by vertebrates.[14]
D. pulex was the first crustacean to have its genome sequenced.[15][16] Its genome contains 31,000 genes – 8,000 more than are present in the human genome – as a result of extensive gene duplication.[17]
One of the most astonishing features of the D. pulex genome is its compactness: despite being around 200 megabase pairs (Mbp) in size (around 1/16th of that of the human genome, which is 3,200 Mbp in size); its 12 chromosomes contain a minimum set of 30,907 predicted protein-coding genes, more than the 20,000–25,000 contained in the human counterpart.[17]
Such an efficient gene packaging is achieved by means of a small intron size. Indeed, whereas the mean protein length in D. pulex is quite similar to that of Drosophila, the average gene size is 1000 bp shorter in D. pulex. As inferred from expressed sequence tag analysis, the average intron size found in D. pulex genes is 170 bp.[17]
The intron density of the D. pulex genome, though, is similar to that of Apis mellifera, which in turn is twice that found in Drosophila.[17]
The D. pulex genome has undergone extensive gene duplication followed by rapid paralog divergence and tandem rearrangement. As a result of these processes, around 20% of its gene catalog is composed of tandems consisting of three to 80 paralog genes, many of which are ecoresponsive, that is, they are expressed differently upon exposure of D. pulex to environmental challenges such as biotic or abiotic stress or fluctuations in light or oxygen levels.[17]
D. pulex can reproduce by cyclical parthenogenesis or obligate parthenogenesis.[18] During cyclical parthenogenesis D. pulex cycles between a sexual stage and a parthenogenetic stage. During the sexual stage females produce haploid eggs by meiosis, and these eggs require fertilization by a male to develop further. During the parthenogenetic stage, eggs are produced that do not require fertilization to develop further. The lineages of D. pulex that reproduce by obligate parthenogenesis also do not require fertilization and produce direct-developing eggs that are indistinguishable from eggs produced by parthenogenesis in cyclical lineages.[18] Parthenogenesis appears to involve initial meiotic chromosome pairing. During both cyclic and obligate parthenogenesis a polar body is extruded during cell division indicating initiation of meiosis.
Daphnia pulex is the most common species of water flea. It has a cosmopolitan distribution: the species is found throughout the Americas, Europe, and Australia. It is a model species, and was the first crustacean to have its genome sequenced.
Daphnia pulex es la especie más común dentro de las pulgas de agua.[3] Tiene una distribución geográfica muy amplia: se la puede encontrar en toda América, Europa y Australia.[4]
Es una especie muy utilizada como modelo experimental; y además es el primer crustáceo del cual se ha secuenciado su genoma.
A pesar de que Daphnia pulex es un artrópodo, sus segmentos corporales son difíciles de reconocer. Se pueden distinguir por los apéndices que poseen (un par de apéndices por cada segmento) y también estudiando la anatomía interna.[5] La cabeza se distingue claramente y se forma a partir de la fusión de seis segmentos en el estadio embrional.[5] En ella destacan la boca y dos pares de antenas, el segundo de los cuales ha aumentado su tamaño para convertirse en poderosos apéndices natatorios. No existe una división clara entre tórax y abdomen, que en conjunto poseen 5 pares de apéndices.[5] El caparazón que rodea al animal se extiende en sentido posterior terminando en una espina de longitud variable.[6]
Daphnia pulex puede vivir en una gran variedad de hábitats acuáticos, aunque se encuentra preferentemente en charcas pequeñas y con iluminación moderada.[7]
No tiene prácticamente pigmentación alguna en circunstancias oligotróficas en las que hay escasez de nutrientes. Por el contrario, en condiciones eutróficas D. pulex se vuelve de un color rojo intenso, debido al aumento en la producción de hemoglobina.[7]
Daphnia constituye una presa importante para depredadores vertebrados e invertebrados. Se ha estudiado en detalle la influencia de los depredadores sobre la dinámica de poblaciones,[8] distribución y otros aspectos ecológicos[9]de la especie D. pulex , comprobándose que juega un papel fundamental . Además de los efectos directos de la acción depredadora sobre el tamaño de las poblaciones de D. pulex existe una influencia evolutiva sobre el fenotipo que puede producir efectos opuestos según las circunstancias: los ejemplares de D. pulex de mayor tamaño son más visibles para los depredadores vertebrados, mientras que los depredadores invertebrados son incapaces de ingerirlos. Como resultado de esto, el fenotipo de mayor tamaño se ve favorecido y prevalece en presencia de depredadores invertebrados mientras que cuando existen depredadores vertebrados tienen ventaja los individuos más pequeños.
Como en el caso de otras especies de Daphnia, D. pulex exhibe una considerable plasticidad fenotípica, cambiando su morfología al detectar la presencia de depredadores, como por ejemplo las larvas del díptero Chaoborus que se alimentan de los individuos en estadios juveniles de D. pulex. Las larvas de Chaoborus producen feromonas (kairomonas) que delatan su presencia al ser reconocidas por los juveniles de D.pulex, que responden desarrollando unas protuberancias afiladas (“dientes de cuello”) en la siguiente muda de caparazón.[10]El uso de los dientes de cuello como estrategia de defensa aumenta la supervivencia de D. pulex frente a este depredador invertebrado, pero a costa de alargar su período de desarrollo.[11]
La estequiometría ecológica, entendida como la disponibilidad y el balance de nutrientes, ejerce una gran influencia en las características de Daphnia pulex.[12] La escasez de nutrientes provoca una reducción en el tamaño corporal y en la tasa de crecimiento, las cuales, como se ha mencionado antes, también son muy importantes en la relación de Daphnia con sus depredadores. En este sentido, Daphnia pulex constituye una especie modelo muy importante para investigaciones relacionadas con la estequiometría ecológica, y se ha utilizado por ejemplo para estudiar las relaciones entre la abundancia de fitoplancton (algas microscópicas que constituye el alimento principal de D. pulex), la capacidad de fijación del carbono, la intensidad de luz natural (comparando poblaciones de charcas con árboles cercanos con otras que están a pleno sol), los niveles de nutrientes inorgánicos y el tamaño corporal de D. pulex.[13]
Daphnia pulex es el primer crustáceo cuyo genoma ha sido secuenciado.[14][15] Su genoma contiene 31.000 genes – 8.000 más que en el genoma humano – como resultado de una extensa duplicación génica.[16]
Una de las características más sorprendentes del genoma de D. pulex es su naturaleza compacta: a pesar de tener un tamaño de 200 Mb (aproximadamente 16 veces más pequeño que el genoma humano, el cual tiene 3.200 Mb); en sus 12 cromosomas se predice que hay al menos 30.907 genes codificantes de proteínas, más que los 20.000-25.000 predichos para el genoma humano.[16]
Este empaquetamiento tan eficiente se obtiene gracias a un tamaño intrónico muy pequeño. En efecto, mientras que la longitud media por proteína en D. pulex es muy similar a la de Drosophila, la longitud media por gen es 1000 bp más corta en D. pulex. Según estudios basado en EST, la longitud media por intrón en los genes de D. pulex es de 170 bp.[16]
Por otra parte, la densidad de intrones a lo largo del genoma de D. pulex es similar a la de Apis mellifera, la cual a su vez es el doble que la de Drosophila.[16]
El genoma de D. pulex ha experimentado una intensa duplicación génica seguida de una rápida divergencia y reordenamiento en clústeres de los genes parálogos. Como resultado, alrededor del 20% del catálogo de genes de D. pulex está formado por clústeres de 3-80 parálogos dispuestos en tándem, muchos de los cuales son eco-sensibles, es decir que se expresan de modo diferencial en respuesta a condiciones cambiantes del entorno, por ejemplo estrés biótico o abiótico o bien fluctuaciones en los niveles de oxígeno y/o luz.[16]
Datos: Q1080188
Multimedia:
Especies: Daphnia pulex
Daphnia pulex es la especie más común dentro de las pulgas de agua. Tiene una distribución geográfica muy amplia: se la puede encontrar en toda América, Europa y Australia.
Es una especie muy utilizada como modelo experimental; y además es el primer crustáceo del cual se ha secuenciado su genoma.
Lombi kiivrik ehk kammkiivrik (Daphnia pulex) on Daphniidae sugukonda vesikirbu perekonda kuuluv vähilaadne.
Ta on esimene vähilaadne, kelle genoom on järjestatud.
Emaste isendite pikkus on 3-4 mm ja isaste oma 1-1,5 mm.
Teda leidub Euroopa (sh Eesti), Ameerika ja Austraalia veekogudes.
Lombi kiivrik ehk kammkiivrik (Daphnia pulex) on Daphniidae sugukonda vesikirbu perekonda kuuluv vähilaadne.
Ta on esimene vähilaadne, kelle genoom on järjestatud.
Emaste isendite pikkus on 3-4 mm ja isaste oma 1-1,5 mm.
Teda leidub Euroopa (sh Eesti), Ameerika ja Austraalia veekogudes.
Daphnia pulex est une espèce de crustacés d'eau douce de la famille des Daphniidae. C'est l'espèce de daphnies la plus commune.
Daphnia pulex est une espèce de crustacés d'eau douce de la famille des Daphniidae. C'est l'espèce de daphnies la plus commune.
Daphnia pulex Leydig, 1860[1] è un piccolo crostaceo cladocero planctonico, appartenente al genere Daphnia. Ha una distribuzione subcosmopolita: la specie si trova nelle Americhe, in Europa e in Australia.
È un organismo modello utilizzato in studi di ecologia genomica come indicatore comportamentale.[2][3]
Daphnia pulex Leydig, 1860 è un piccolo crostaceo cladocero planctonico, appartenente al genere Daphnia. Ha una distribuzione subcosmopolita: la specie si trova nelle Americhe, in Europa e in Australia.
È un organismo modello utilizzato in studi di ecologia genomica come indicatore comportamentale.
Daphnia pulex is een watervlooiensoort uit de familie van de Daphniidae.[1] De wetenschappelijke naam van de soort is voor het eerst geldig gepubliceerd in 1860 door Leydig.
Bronnen, noten en/of referenties
Multimedia w Wikimedia Commons Rozwielitka pchłowata, rozwielitka pchlica (Daphnia (Daphnia) pulex) – gatunek wioślarki z rodzaju Daphnia i podrodzaju Daphnia s. str., należący do rodziny Daphniidae.
Rozwielitka pchłowata ma kształt owalny lub kulisty i jest bardzo delikatna. Skorupka jest prześwitująca i może być żółtawa, brązowawa lub zielonkawa. Rozwielitki mają krótkie czułki I pary (ze szczecinkami czuciowymi na końcu) i długie czułki II pary. Męskie osobniki sięgają rozmiarów 1,0–1,8 mm, natomiast żeńskie 1,1–3,5 mm[2].
Jest jedną z najpospolitszych wioślarek. Odnóża tułowiowe służą do chwytania pokarmu (m.in. glonów) lub napędzania go do otworu gębowego. Poruszają się w wodzie skokami za pomocą czułków drugiej pary. Żyją w tymczasowych i trwałych stawach oraz małych jeziorach. Rozmnażają się płciowo jak i dzieworodnie.
Rozwielitka pchłowata, rozwielitka pchlica (Daphnia (Daphnia) pulex) – gatunek wioślarki z rodzaju Daphnia i podrodzaju Daphnia s. str., należący do rodziny Daphniidae.
A Daphnia pulex é uma espécie de pulga de água que teve a publicação do sequenciamento de seu genoma ocorrida em 2011.[1] Possui o maior número de genes entre todas as espécies já avaliadas, 31 mil, sendo que em humanos este número é de 23 mil. Seu DNA foi mapeado por cientistas do Daphnia Genomics Consortium.[2]
A Daphnia pulex é uma espécie de pulga de água que teve a publicação do sequenciamento de seu genoma ocorrida em 2011. Possui o maior número de genes entre todas as espécies já avaliadas, 31 mil, sendo que em humanos este número é de 23 mil. Seu DNA foi mapeado por cientistas do Daphnia Genomics Consortium.
Stare de conservareClasificare științificăSupradomeniu[*]BiotaSupraregn[*]EukaryotaRegnAnimaliaSubregnBilateriaInfraregn[*]ProtostomiaSuperîncrengătură[*]EcdysozoaÎncrengăturăArthropodaSubîncrengăturăCrustaceaSubîncrengăturăCrustaceaClasăBranchiopodaSubclasă[*]PhyllopodaOrdinDiplostracaSubordin[*]CladoceraInfraordin[*]AnomopodaFamilieDaphniidaeGenDaphniaNume binomialDaphnia pulex[1]Modifică date / text 
Puricele de apă (Daphnia pulex, dafnie) este un crustaceu mic care, fiind folosit de zeci de ani pentru a analiza schimbările din cadrul ecosistemelor, a devenit ființa cu cel mai mare număr de gene: 30.000 (cu 10.000 mai multe decât omul).
Acest articol despre biologie este un ciot. Puteți ajuta Wikipedia prin completarea sa. Puricele de apă (Daphnia pulex, dafnie) este un crustaceu mic care, fiind folosit de zeci de ani pentru a analiza schimbările din cadrul ecosistemelor, a devenit ființa cu cel mai mare număr de gene: 30.000 (cu 10.000 mai multe decât omul).
Daphnia pulex là loài phổ biến nhất nhất của bộ Cladocera.[3] Nó là một loài có phân bố quốc tế, được tìm thấy trên khắp Châu Mỹ, Châu Âu và Úc.[4] Nó là một loài sinh vật mô hình và là loài giáp xác đầu tiên có trình tự gen.
Daphnia pulex xuất hiện trong một loạt các môi trường sống dưới nước, mặc dù nó có liên quan chặt chẽ nhất với các hồ nhỏ và tối.[5] Trong hồ nghèo dinh dưỡng, D. pulex có rất ít sắc tố, trong khi nó có thể trở thành màu đỏ tươi trong nước giàu dinh dưỡng do việc sản xuất hemoglobin.[5]
Daphnia pulex là loài phổ biến nhất nhất của bộ Cladocera. Nó là một loài có phân bố quốc tế, được tìm thấy trên khắp Châu Mỹ, Châu Âu và Úc. Nó là một loài sinh vật mô hình và là loài giáp xác đầu tiên có trình tự gen.
Обыкновенная дафния[1] (лат. Daphnia pulex) — вид ракообразных семейства дафнид. Первое ракообразное животное, чей геном был расшифрован.
Тело овальной формы, зеленоватого, желтоватого или красноватого цвета и часто мало прозрачное. Самки длиной от 3 до 4 мм, самцы — от 1 до 1,5 мм. Для самцов характерны длинные первые антенны и выделяющиеся крючки на первой паре ног. В голове имеется один крупный фасеточный глаз, состоящий из 22 отдельных фасеток (омматидиев).
Обыкновенная дафния распространена в Европе, Америке и Австралии. Вид обитает в небольших прудах, а также в прибрежной зоне больших водоёмов. Часто встречается в больших скоплениях.
Обыкновенная дафния (лат. Daphnia pulex) — вид ракообразных семейства дафнид. Первое ракообразное животное, чей геном был расшифрован.
蚤状溞（学名：Daphnia pulex）为溞科溞属的动物。分布于世界各地，属于广温性物种，在北纬和中纬地带分布，常见于水潭、水坑、池塘以及小河等小型水域中，在南纬地带出现于湖泊或水库等敞水区。[1]
这是一篇與节肢动物相關的小作品。你可以通过编辑或修订扩充其内容。
물벼룩(영어: water flea)은 물벼룩과에 속하는 생물이다.
민물에 사는 아주 작은 갑각류로, 몸길이는 0.2 ~ 1.8mm이다. 머리는 너비가 넓고 반원 모양으로 등쪽에 붙어 있고 갑각은 배쪽에 붙어 있으며, 두 장의 껍질은 대개 반투명하다. 몸빛은 무색이거나 담황색 또는 담홍색을 띤다. 겹눈은 크고 홑눈은 작고, 겹눈이 하나다.
배 뒷부분에는 양쪽에 12 ~ 18개의 가시가 있다. 머리 앞쪽에서 뻗어나온 더듬이으로 노젓기를 하여 헤엄친다. 한국 기준 5월 쯤 논에서 물벼룩들이 떼거지로 모여 있다.
혈액/순환계는 개방 순환계로, 혈관 없이 오로지 심장과 혈액만 있으며 심장이 피를 뿜으면 물벼룩의 껍데기는 등과 머리만 붙어있는데, 그 틈 속으로 들어온 물을 따라 피가 온 몸에 전해지는 방식이다. 갑각이 투명하기 때문에 현미경으로 잘 관찰하면 심장이 뛰는 모습을 볼 수 있다. 몸집이 작기 때문에 심장이 빨리 뛴다.
사진 상으로 등 쪽에 척추처럼 길게 들어있는 것은 대장이다.
흑갈색의 알을 여름에는 30개, 겨울에는 두 개 가량 낳는데 수정을 하지 않고 유생이 되는 단위생식을 한다. 알은 등 쪽에 들어있으며, 가끔 알 대신 새끼들이 들어있는걸 볼수가 있다. 알이 등 속에 오래 있어서 그런 거라고. 자기 생명에 위협을 느끼면 어미들은 등에 있는 알이나 새끼들을 밖으로 내보낸다. 종족을 지켜내기 위해서 라고 한다.
물벼룩의 먹이는 작은 녹조류이고, 물벼룩은 물고기의 좋은 먹이가 된다. 투명한 갑각이 몸을 감싸고 있어 심장의 박동과 기관의 움직임을 관찰할 수 있기 때문에 독성실험에 자주 이용된다.
