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Unio Crassus
''Unio crassus'', the thick shelled river mussel, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. MolluscaBase eds. (2023). MolluscaBase. Unio crassus Philipsson, 1788. Accessed through: World Register of Marine Species at: https://marinespecies.org/aphia.php?p=taxdetails&id=1044116 on 2023-01-09 ;Subspecies: * † ''Unio crassus jaeckeli'' Modell, 1950 * † ''Unio crassus klemmi'' Modell, 1957 Ecology As part of newly discovered reproductive behaviour, this mollusc crawls up to the edge of the water, exposing its excurrent aperture, and then lets loose a stream of water. The fountain of water often contains glochidia, and it is suggested that this spurting behavior may facilitate dispersal of mussel larvae (video). Decline The thick shelled river mussel declined during the 20th century everywhere in Europe due to deteriorating water quality, habitat fragmentation and host fish limitation. Distribution Its native d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anders Jahan Retzius
Anders Jahan Retzius (3 October 1742 – 6 October 1821) was a Swedish chemist, botanist and entomologist. Biography Born in Kristianstad, he matriculated at Lund University in 1758, where he graduated as a filosofie magister in 1766. He also trained as an apothecary apprentice. He received the position of docent of chemistry at Lund in 1766, and of natural history in 1767. He became extraordinary professor of natural history in 1777, and thereafter held various chairs of natural history, economy and chemistry until his retirement in 1812. He died in Stockholm on 6 October 1821. He described many new species of insects and did fundamental work on their classification. Retzius was elected a member of the Royal Swedish Academy of Sciences in 1782. He was the father of Anders Retzius and grandfather of Gustaf Retzius. Disciples of Anders Jahan Retzius include the botanist Carl Adolph Agardh, the zoologist and archaeologist Sven Nilsson, the botanist and entomologist Carl Fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Asia
Western Asia, West Asia, or Southwest Asia, is the westernmost subregion of the larger geographical region of Asia, as defined by some academics, UN bodies and other institutions. It is almost entirely a part of the Middle East, and includes Anatolia, the Arabian Peninsula, Iran, Mesopotamia, the Armenian Highlands, the Levant, the island of Cyprus, the Sinai Peninsula, and partly the Caucasus Region ( Transcaucasia). The region is considered to be separated from Africa by the Isthmus of Suez in Egypt, and separated from Europe by the waterways of the Turkish Straits and the watershed of the Greater Caucasus. Central Asia lies to its northeast, while South Asia lies to its east. Twelve seas surround the region (clockwise): the Aegean Sea, the Sea of Marmara, the Black Sea, the Caspian Sea, the Persian Gulf, the Gulf of Oman, the Arabian Sea, the Gulf of Aden, the Red Sea, the Gulf of Aqaba, the Gulf of Suez, and the Mediterranean Sea. Western Asia covers an area of , with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalves Of Europe
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bivalves have no head and they lack some usual molluscan organs, like the radula and the odontophore. They include the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment, where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. The shipworms bore into wood, clay, or stone and live inside these substances. The shell of a bivalve is composed of calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalves Of Asia
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bivalves have no head and they lack some usual molluscan organs, like the radula and the odontophore. They include the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment, where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. The shipworms bore into wood, clay, or stone and live inside these substances. The shell of a bivalve is composed of calcium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unio (bivalve)
''Unio'' is a genus of medium-sized freshwater mussels, aquatic bivalve mollusks in the family Unionidae, the river mussels. They are found throughout Europe, Africa, and the Middle East, with some species introduced to East Asia. Fossil species are also known from the Jurassic of North America. ''Unio'' is the type genus of the family Unionidae. Species Species in the genus ''Unio'' include: *'' Unio abyssinicus'' Martens, 1866 *'' Unio bruguierianus'' Bourguignat, 1853 *'' Unio caffer'' Krauss, 1848 *''Unio cariei'' - extinctBouchet, P. & von Cosel, R. 1996.Unio cariei 2006 IUCN Red List of Threatened Species. Downloaded on 7 August 2007. (no longer recognised) *'' Unio courtillieri'' Hattemann, 1859 *''Unio crassus'' Philipsson, 1788 (Thick shelled river mussel) - near threatened *''Unio damascensis'' Lea, 1863 *''Unio delicatus'' Lea, 1863 *''Unio delphinus'' Spengler, 1793 *''Unio dembeae'' Reeve, 1865 *'' Unio durieui'' Deshayes, 1847 *''Unio elongatulus'' C. Pfeiffer, 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinction
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Netherlands
) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherlands , established_title2 = Act of Abjuration , established_date2 = 26 July 1581 , established_title3 = Peace of Münster , established_date3 = 30 January 1648 , established_title4 = Kingdom established , established_date4 = 16 March 1815 , established_title5 = Liberation Day , established_date5 = 5 May 1945 , established_title6 = Kingdom Charter , established_date6 = 15 December 1954 , established_title7 = Caribbean reorganisation , established_date7 = 10 October 2010 , official_languages = Dutch , languages_type = Regional languages , languages_sub = yes , languages = , languages2_type = Recognised languages , languages2_sub = yes , languages2 = , demonym = Dutch , capital = Amsterdam , largest_city = capital , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Extinct Animals Of The Netherlands
This list of extinct animals of the Netherlands includes the animal species and subspecies once lived in the Netherlands but have disappeared since human habitation. This list features the mammals, birds, fish, molluscs, butterflies, dragonflies, bees, pond damselflies, mayflies, grasshoppers and Crickets that have disappeared from the Netherlands. There have been no known extinctions of reptiles or amphibians in the Netherlands. Most animals on this list of extinct animals in the Netherlands survive in other places in the world. However, some of them are now globally extinct, like the great auk (''Pinguinus impennis''), the European wild horse (''Equus ferus'') and the aurochs (''Bos primigenius primigenius''). One skeleton of the great auk was excavated in a Roman settlement near Velsen. Bones were also found near Rotterdam. In the Netherlands there are no bone finds of the aurochs after the Roman period (400 AD). '' Phengaris alcon arenaria'', an endemic Dutch subsp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Commission
The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body of about 32,000 European civil servants. The Commission is divided into departments known as Directorates-General (DGs) that can be likened to departments or ministries each headed by a Director-General who is responsible to a Commissioner. There is one member per member state, but members are bound by their oath of office to represent the general interest of the EU as a whole rather than their home state. The Commission President (currently Ursula von der Leyen) is proposed by the European Council (the 27 heads of state/governments) and elected by the European Parliament. The Council of the European Union then nominates the other members of the Commission in agreement with the nominated President, and the 27 members as a team are t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endangered
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and invasive species. The International Union for Conservation of Nature (IUCN) Red List lists the global conservation status of many species, and various other agencies assess the status of species within particular areas. Many nations have laws that protect conservation-reliant species which, for example, forbid hunting, restrict land development, or create protected areas. Some endangered species are the target of extensive conservation efforts such as captive breeding and habitat restoration. Human activity is a significant cause in causing some species to become endangered. Conservation status The conservation status of a species indicates the likelihood that it will become extinct. Multiple factors are considered when assessi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Non-marine Molluscs Of The Czech Republic
This is a list of the non-marine molluscs of the Czech Republic. That country is land-locked and therefore it has no marine molluscs, only land and freshwater species, including snails, slugs, freshwater clams and freshwater mussels. There are 247 species of molluscs living in the wild in the Czech Republic. In addition there are at least 11 gastropod species surviving in greenhouses. There are 219 gastropod species (50 freshwater and 169 land species) and 28 bivalve species living in the wild. There are also 11 introduced gastropod species (5 freshwater and 7 land species) and 4 bivalve species living in the wild in the Czech Republic. This is a total of 9 freshwater non-indigenous species living in natural habitats. ;Summary table of number of species There are 2 endemic species of molluscs in the Czech Republic: *'' Alzoniella slovenica'' in Moravia (and in Slovakia too) *'' Bulgarica nitidosa'' in Bohemia. History Historical lists from 19th century or overviews o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitats Directive
The Habitats Directive (more formally known as Council Directive 92/43/EEC on the Conservation of natural habitats and of wild fauna and flora) is a directive adopted by the European Community in 1992 as a response to the Berne Convention. The European Community was reformed as the European Union the following year, but the directive is still recognised. The Habitats Directive required national governments to specify areas that are expected to be ensuring the conservation of flora and fauna species. This led to the setting up of a network of protected areas across the EU, along with ' Special Areas of Conservation', which together with the existing Special Protection Areas, became the so-called Natura 2000 network established to protect species and habitats. This directive is one of the main pillars of the European Union's system of wildlife and nature conservation, another being the Birds Directive. The Habitats Directive, together with the Birds Directive, are also called th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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