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Marmorkrebs
The marbled crayfish or (''Procambarus virginalis'') is a parthenogenetic crayfish that was discovered in the pet trade in Germany in 1995. Marbled crayfish are closely related to the "slough crayfish", '' Procambarus fallax'', which is widely distributed across Florida. No natural populations of marbled crayfish are known. Information provided by one of the original pet traders as to where the marbled crayfish originated was deemed "totally confusing and unreliable". The informal name ''Marmorkrebs'' is German for "marbled crayfish". Model organism Marbled crayfish are the only known decapod crustaceans to reproduce only by parthenogenesis. All individuals are female, and the offspring are genetically identical to the parent. Marbled crayfish are triploid animals with 276 chromosomes, which may be the main reason for their parthenogenetic reproduction. It is hypothesized that marbled crayfish originated from an error in meiosis resulting in a diploid gamete, which was then fer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marmorkrebs Lorenz Seebauer SingliserSee Germany
The marbled crayfish or (''Procambarus virginalis'') is a parthenogenetic crayfish that was discovered in the pet trade in Germany in 1995. Marbled crayfish are closely related to the "slough crayfish", '' Procambarus fallax'', which is widely distributed across Florida. No natural populations of marbled crayfish are known. Information provided by one of the original pet traders as to where the marbled crayfish originated was deemed "totally confusing and unreliable". The informal name ''Marmorkrebs'' is German for "marbled crayfish". Model organism Marbled crayfish are the only known decapod crustaceans to reproduce only by parthenogenesis. All individuals are female, and the offspring are genetically identical to the parent. Marbled crayfish are triploid animals with 276 chromosomes, which may be the main reason for their parthenogenetic reproduction. It is hypothesized that marbled crayfish originated from an error in meiosis resulting in a diploid gamete, which was then fer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parthenogenesis
Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and development of embryos occur in a gamete (egg or sperm) without combining with another gamete (e.g., egg and sperm fusing). In animals, parthenogenesis means development of an embryo from an unfertilized Gametophyte, egg cell. In plants, parthenogenesis is a component process of apomixis. In algae, parthenogenesis can mean the development of an embryo from either an individual sperm or an individual egg. Parthenogenesis occurs naturally in some plants, algae, invertebrate animal species (including nematodes, some tardigrades, water fleas, some scorpions, aphids, some mites, some bees, some Phasmatodea and parasitic wasps) and a few vertebrates (such as some fish, amphibians, reptiles and birds). This type of reproduction has been induced artificially ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procambarus Fallax
''Procambarus fallax'' (also known as slough crayfish) is a species of crayfish in the genus ''Procambarus''. It lives in tributaries of the Satilla River in Georgia and Florida. It is the closest relative to the parthenogenetic Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and developmen ... marbled crayfish, ''Procambarus virginalis''. External links Photos of Procambarus fallax. By meteorologistsam (CC BY-NC 4.0) https://www.gbif.org/pt/occurrence/3008543956 References Cambaridae Freshwater crustaceans of North America Crustaceans described in 1870 Endemic fauna of the United States Fauna of the Southeastern United States Taxa named by Hermann August Hagen {{Crayfish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods emerged deep in the Crustacean group, with the completed group referred to as Pancrustacea. Some crustaceans (Remipedia, Cephalocarida, Branchiopoda) are more closely related to insects and the other hexapods than they are to certain other crustaceans. The 67,000 described species range in size from '' Stygotantulus stocki'' at , to the Japanese spider crab with a leg span of up to and a mass of . Like other arthropods, crustaceans have an exoskeleton, which they moult to grow. They are distinguished from other groups of arthropods, such as insects, myriapods and chelicerates, by the possession of biramous (two-parted) limbs, and by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belgium
Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to the southwest, and the North Sea to the northwest. It covers an area of and has a population of more than 11.5 million, making it the 22nd most densely populated country in the world and the 6th most densely populated country in Europe, with a density of . Belgium is part of an area known as the Low Countries, historically a somewhat larger region than the Benelux group of states, as it also included parts of northern France. The capital and largest city is Brussels; other major cities are Antwerp, Ghent, Charleroi, Liège, Bruges, Namur, and Leuven. Belgium is a sovereign state and a federal constitutional monarchy with a parliamentary system. Its institutional organization is complex and is structured on both regional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invasive Species
An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native species that become harmful to their native environment after human alterations to its food webfor example the purple sea urchin (''Strongylocentrotus purpuratus'') which has decimated kelp forests along the northern California coast due to overharvesting of its natural predator, the California sea otter (''Enhydra lutris''). Since the 20th century, invasive species have become a serious economic, social, and environmental threat. Invasion of long-established ecosystems by organisms is a natural phenomenon, but human-facilitated introductions have greatly increased the rate, scale, and geographic range of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crayfish Plague
Crayfish plague (''Aphanomyces astaci'') is a water mold that infects crayfish, most notably the European ''Astacus'' which dies within a few weeks of being infected. When experimentally tested, species from Australia, New Guinea and Japan were also found to be susceptible to the infection. History Crayfish plague first arrived in Europe in Italy in 1859, either with imported crayfish from North America, or in ballast water discharge. After its original introduction in Italy in 1860, it spread quickly through Europe and was discovered in Sweden in 1907, in Spain in 1972, in Norway in 1971, in Great Britain in 1981, in Turkey in 1984 and in Ireland in 1987. In 1959, to bolster dwindling stocks of native crayfish, the signal crayfish was introduced to Sweden. The signal crayfish was known to be resistant, and it was not recognised at that time that it was a carrier of the disease. After 150 years of contact, no resistance has been discovered in native European crayfish. This spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Austria
Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous city and state. A landlocked country, Austria is bordered by Germany to the northwest, the Czech Republic to the north, Slovakia to the northeast, Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the west. The country occupies an area of and has a population of 9 million. Austria emerged from the remnants of the Eastern and Hungarian March at the end of the first millennium. Originally a margraviate of Bavaria, it developed into a duchy of the Holy Roman Empire in 1156 and was later made an archduchy in 1453. In the 16th century, Vienna began serving as the empire's administrative capital and Austria thus became the heartland of the Habsburg monarchy. After the dissolution of the H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Czech Republic
The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The Czech Republic has a hilly landscape that covers an area of with a mostly temperate continental and oceanic climate. The capital and largest city is Prague; other major cities and urban areas include Brno, Ostrava, Plzeň and Liberec. The Duchy of Bohemia was founded in the late 9th century under Great Moravia. It was formally recognized as an Imperial State of the Holy Roman Empire in 1002 and became a kingdom in 1198. Following the Battle of Mohács in 1526, the whole Crown of Bohemia was gradually integrated into the Habsburg monarchy. The Protestant Bohemian Revolt led to the Thirty Years' War. After the Battle of White Mountain, the Habsburgs consolidated their rule. With the dissolution of the Holy Empire in 1806, the Cro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Croatia
, image_flag = Flag of Croatia.svg , image_coat = Coat of arms of Croatia.svg , anthem = "Lijepa naša domovino"("Our Beautiful Homeland") , image_map = , map_caption = , capital = Zagreb , coordinates = , largest_city = capital , official_languages = Croatian , languages_type = Writing system , languages = Latin , ethnic_groups = , ethnic_groups_year = 2021 , religion = , religion_year = 2021 , demonym = , government_type = Unitary parliamentary republic , leader_title1 = President , leader_name1 = Zoran Milanović , leader_title2 = Prime Minister , leader_name2 = Andrej Plenković , leader_title3 = Speaker of Parliament , leader_name3 = Gordan Jandroković , legislature = Sabor , sovereignty_type ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Developmental Biology
Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of Regeneration (biology), regeneration, asexual reproduction, metamorphosis, and the growth and differentiation of stem cells in the adult organism. Perspectives The main processes involved in the embryogenesis, embryonic development of animals are: tissue patterning (via regional specification and patterned cellular differentiation, cell differentiation); tissue growth; and tissue morphogenesis. * Regional specification refers to the processes that create the spatial patterns in a ball or sheet of initially similar cells. This generally involves the action of cytoplasmic determinants, located within parts of the fertilized egg, and of inductive signals emitted from signaling centers in the embryo. The early stages of regional specification do not generate functional differentiated cells, but cell populations committed to developing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estonia
Estonia, formally the Republic of Estonia, is a country by the Baltic Sea in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the sea across from Sweden, to the south by Latvia, and to the east by Lake Peipus and Russia. The territory of Estonia consists of the mainland, the larger islands of Saaremaa and Hiiumaa, and over 2,200 other islands and islets on the eastern coast of the Baltic Sea, covering a total area of . The capital city Tallinn and Tartu are the two largest urban areas of the country. The Estonian language is the autochthonous and the official language of Estonia; it is the first language of the majority of its population, as well as the world's second most spoken Finnic language. The land of what is now modern Estonia has been inhabited by '' Homo sapiens'' since at least 9,000 BC. The medieval indigenous population of Estonia was one of the last " pagan" civilisations in Europe to adopt Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
