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Lamprey Larva X Sect Pharynx Labelled
Lampreys (sometimes inaccurately called lamprey eels) are an ancient extant lineage of jawless fish of the order Petromyzontiformes , placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like sucking mouth. The common name "lamprey" is probably derived from Latin , which may mean "stone licker" ( "to lick" + "stone"), though the etymology is uncertain. ''Lamprey'' is sometimes seen for the plural form. There are about 38 known extant species of lampreys and five known extinct species. Parasitic carnivorous species are the most well-known, and feed by boring into the flesh of other fish to suck their blood; but only 18 species of lampreys engage in this micropredatory lifestyle. Of the 18 carnivorous species, nine migrate from saltwater to freshwater to breed (some of them also have freshwater populations), and nine live exclusively in freshwater. All non-carnivorous forms are freshwater species. Adults of the non-carnivorous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European River Lamprey
The European river lamprey (''Lampetra fluviatilis''), also known as the river lamprey or lampern, is a species of freshwater lamprey. Description Adult river lampreys measure from for the sea-going forms and up to for the lake forms. The very elongate body is a uniform dark grey above, lightening to yellowish off-white on the sides and pure white below. Like all lampreys, these fish lack paired fins and possess a circular sucking disc instead of jaws. They have a single nostril and seven small breathing holes on either side behind the eye. The teeth are sharp and these fish can be told from the rather smaller brook lamprey (''Lampetra planeri'') by the fact that the two dorsal fins are more widely separated. Distribution The European river lamprey is found in coastal waters around almost all of Europe from the north-west Mediterranean Sea north to the lakes of Finland, Scotland, Norway (Mjøsa), Wales (Cors Caron), and Russia, including rivers in the Alps; especially in Nakkila ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxford University Press
Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print books by decree in 1586, it is the second oldest university press after Cambridge University Press. It is a department of the University of Oxford and is governed by a group of 15 academics known as the Delegates of the Press, who are appointed by the vice-chancellor of the University of Oxford. The Delegates of the Press are led by the Secretary to the Delegates, who serves as OUP's chief executive and as its major representative on other university bodies. Oxford University Press has had a similar governance structure since the 17th century. The press is located on Walton Street, Oxford, opposite Somerville College, in the inner suburb of Jericho. For the last 500 years, OUP has primarily focused on the publication of pedagogical texts and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Wear
The River Wear (, ) in North East England rises in the Pennines and flows eastwards, mostly through County Durham to the North Sea in the City of Sunderland. At long, it is one of the region's longest rivers, wends in a steep valley through the cathedral city of Durham and gives its name to Weardale in its upper reach and Wearside by its mouth. Etymology The origin behind the hydronym ''Wear'' is uncertain but is generally understood to be Celtic. The ''River Vedra'' on the Roman Map of Britain may very well be the River Wear. The name may be derived from Brittonic ''*wejr'' (<''*wẹ:drā''), which meant "a bend" (c.f ''-gwair-''). An alternative but very problematic etymology might involve ''*wẹ:d-r-'', from a lengthened form of the |
Petersham, London
Petersham is a village in the London Borough of Richmond upon Thames on the east of the bend in the River Thames south of Richmond, which it shares with neighbouring Ham. It provides the foreground of the scenic view from Richmond Hill across Petersham Meadows, with Ham House further along the river. Other nearby places include Twickenham, Isleworth, Teddington, Mortlake and Roehampton. History Petersham appears in the Domesday Book of 1086 as ''Patricesham''. It was held by Chertsey Abbey. Its assets were: 4 hides; 1 church, 5 ploughs, 1 fishery worth 1000 eels and 1000 lampreys, of meadow. It rendered £6 10s 0d. The village was the birthplace in 1682 of Archibald Campbell, later 3rd Duke of Argyll and Earl of Islay. He went on to found the Royal Bank of Scotland in Edinburgh in 1727, and his face is on the obverse of all of the Royal Bank's current paper banknotes. The explorer George Vancouver retired to Petersham, where he wrote ''A Voyage Of Discovery to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Thames
The River Thames ( ), known alternatively in parts as the The Isis, River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the Longest rivers of the United Kingdom, second-longest in the United Kingdom, after the River Severn. The river rises at Thames Head in Gloucestershire, and flows into the North Sea near Tilbury, Essex and Gravesend, Kent, via the Thames Estuary. From the west it flows through Oxford (where it is sometimes called the Isis), Reading, Berkshire, Reading, Henley-on-Thames and Windsor, Berkshire, Windsor. The Thames also drains the whole of Greater London. In August 2022, the source of the river moved five miles to beyond Somerford Keynes due to the heatwave in July 2022. The lower reaches of the river are called the Tideway, derived from its long tidal reach up to Teddington Lock. Its tidal section includes most of its London stretch and has a rise and fall of . From Oxford to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norman Conquest Of England
The Norman Conquest (or the Conquest) was the 11th-century invasion and occupation of England by an army made up of thousands of Normans, Norman, Duchy of Brittany, Breton, County of Flanders, Flemish, and Kingdom of France, French troops, all led by the Duke of Normandy, later styled William the Conqueror. William's claim to the English throne derived from his familial relationship with the childless Anglo-Saxon king Edward the Confessor, who may have encouraged William's hopes for the throne. Edward died in January 1066 and was succeeded by his brother-in-law Harold Godwinson. The Norwegian king Harald Hardrada invaded northern England in September 1066 and was victorious at the Battle of Fulford on 20 September, but Godwinson's army defeated and killed Hardrada at the Battle of Stamford Bridge on 25 September. Three days later on 28 September, William's invasion force of thousands of men and hundreds of ships landed at Pevensey in Sussex in southern England. Harold march ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproductive Isolation
The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offspring are sterile. These barriers maintain the integrity of a species by reducing gene flow between related species.Strickberger, M. 1978. ''Genética''. Omega, Barcelona, España, p.: 874-879. .Futuyma, D. 1998. ''Evolutionary biology'' (3ª edición). Sinauer, Sunderland. The mechanisms of reproductive isolation have been classified in a number of ways. Zoologist Ernst Mayr classified the mechanisms of reproductive isolation in two broad categories: pre-zygotic for those that act before fertilization (or before mating in the case of animals) and post-zygotic for those that act after it.Mayr, E. 1963. ''Animal species and evolution''. Harvard University Press, Cambridge. The mechanisms are genetically controlled and can appear in species whose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entosphenus Tridentatus
The Pacific lamprey (''Entosphenus tridentatus'') is an anadromous parasitic lamprey from the Pacific Coast of North America and Asia. It is a member of the Petromyzontidae family. The Pacific lamprey is also known as the three-tooth lamprey and tridentate lamprey. Description Pacific lampreys grow to about as adults. They are anadromous and semelparous. They have slender, elongated bodies with two dorsal fins arising far back on the body. The anal fins are rudimentary and the lower lobe of the caudal fin is larger than the upper lobe and both lobes are continuous with the dorsal fin and the anal fin. Adults living in the sea are a bluish-black or greenish colour above and pale below, but those in fresh water are brown. This species is distinguished by having three (or occasionally two) sharp teeth on the supraoral bar above the mouth and three sharp points on each lateral plate. The Pacific lamprey are often found at sea or often far offshore. At sea, depth: near surface to 1, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geotria Australis
The pouched lamprey (''Geotria australis''), also known as the korokoro or wide-mouthed lamprey, is a species in the genus ''Geotria'', which is the only genus in the family Geotriidae. The second species in the genus is the Argentinian lamprey (''Geotria macrostoma''), which was revalidated as a separate species in 2020. The pouched lamprey is native to the southern hemisphere. It spends the early part of its life in fresh water, migrating to the sea as an adult, and returning to fresh water to spawn and die. Description ''G. australis'', like other lampreys, has a thin eel-like body, and grows up to long. It has two low dorsal fins on the back half. Like other lampreys, it has no jaws, only a sucker. The skin is a striking silver in adult lampreys caught fresh from the sea but soon changes to brown after they have been in fresh water for some time, due to deposition of biliverdin. Adult eyes are relatively small and located on the side of the head. When fully mature, males de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filter Feeder
Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish (including some sharks). Some birds, such as flamingos and certain species of duck, are also filter feeders. Filter feeders can play an important role in clarifying water, and are therefore considered ecosystem engineers. They are also important in bioaccumulation and, as a result, as indicator organisms. Fish Most forage fish are filter feeders. For example, the Atlantic menhaden, a type of herring, lives on plankton caught in midwater. Adult menhaden can filter up to four gallons of water a minute and play an important role in clarifying ocean water. They are also a natural check to the deadly red tide. Extensive article on the role of menhaden in the ecosystem and possible resul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The larva's appearance is generally very different from the adult form (''e.g.'' caterpillars and butterflies) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different. Larvae are frequently adapted to different environments than adults. For example, some larvae such as tadpoles live almost exclusively in aquatic environments, but can live outside water as adult frogs. By living in a distinct environment, larvae may be given shelter from predators and reduce competition for resources with the adult population. Animals in the larval stage will consume food to fuel their transition into the adult form. In some organisms like polychaetes and barnacles, adults are immobil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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