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Rock Whitebeam
''Aria rupicola'', commonly known as rock whitebeam, is a rare species of shrub or small tree best known from the British Isles but also reported from Norway, Sweden and Russia. Reaching heights of 10 m,''New Flora of the British Isles''; Clive Stace; Third edition; 2011 printing it grows in rocky woodland, scrub and cliffs, usually on limestone. The species reproduces Apomixis, apomictically (asexually via cloned seeds) and was presumably created by Polyploidy, autopolyploidysation of the common whitebeam proper (''Sorbus aria s.str.''). It contains a tetraploidal set of chromosomes (2n=4x=68). Stace gives ''Aria rupicola'' the following characteristics: * Leaves unlobed or lobed ≤1/20 of the way to the midrib. * Leaves with a single style of teeth or, weakly, two styles of teeth. * Leaves with 6 to 9 (rarely 4 to 10) pairs of lateral veins. * Leaves mostly 1.6 to 2.4 times longer than wide. * Leaves mostly widest in that half of the leaf furthest from the stalk. * Leaves usu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trondheimsfjord
The Trondheim Fjord or Trondheimsfjorden (), an inlet of the Norwegian Sea, is Norway's third-longest fjord at long. It is located in the west-central part of the country in Trøndelag county, and it stretches from the municipality of Ørland in the west to the municipality of Steinkjer in the north, passing the city of Trondheim on its way. Its maximum depth is , between Orkland and Indre Fosen. The largest islands in the fjord are Ytterøya and Tautra; the small island of Munkholmen is located near the harbor of Trondheim; and there are several islands at the entrance of the fjord. The narrow ''Skarnsundet'' is crossed by the Skarnsund Bridge. The part of the fjord to the north of the strait is referred to as the ''Beitstadfjorden''. The main part of the Trondheimsfjord is ice-free all year; only Verrasundet, a long and narrow fjord branch in the northern part of the fjord, might be ice covered in winter. The Beitstadfjorden might also freeze over in winter, but only for a few ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Isles
The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, and over six thousand smaller islands."British Isles", ''Encyclopædia Britannica''. They have a total area of and a combined population of almost 72 million, and include two sovereign states, the Republic of Ireland (which covers roughly five-sixths of Ireland), and the United Kingdom of Great Britain and Northern Ireland. The Channel Islands, off the north coast of France, are normally taken to be part of the British Isles, even though they do not form part of the archipelago. The oldest rocks are 2.7 billion years old and are found in Ireland, Wales and the northwest of Scotland. During the Silurian period, the north-western regions collided with the south-east, which had been part of a separate continental landmass. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clive Stace
Clive Anthony Stace (born 1938) is a British botanist and botanical author. He studied at King's College London, graduated from University of London in 1959 and then studied at the Natural History Museum, London. He was awarded a PhD in 1963. His academic career was based at the University of Leicester, where he held the post of Professor of Plant taxonomy. He is a past president of the Botanical Society of Britain and Ireland from 1987 to 1989. The '' New Flora of the British Isles'', first published in 1991 with subsequent revised editions, is considered the authoritative and comprehensive flora of the British Isles for the late twentieth and early twenty-first century. It aims to include all the taxa that could reasonably found in the British Isles during the year and also to keep up with developments in taxonomy. The second edition was substantially improved over the first in terms of general appearance, typography and illustrations as well as by including chromosome numbers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apomixis
In botany, apomixis is asexual reproduction without fertilization. Its etymology is Greek for "away from" + "mixing". This definition notably does not mention meiosis. Thus "normal asexual reproduction" of plants, such as propagation from cuttings or leaves, has never been considered to be apomixis, but replacement of the seed by a plantlet or replacement of the flower by bulbils were categorized as types of apomixis. Apomictically produced offspring are genetically identical to the parent plant. Some authors included all forms of asexual reproduction within apomixis, but that generalization of the term has since died out. In flowering plants, the term "apomixis" is commonly used in a restricted sense to mean agamospermy, i.e., clonal reproduction through seeds. Although agamospermy could theoretically occur in gymnosperms, it appears to be absent in that group. Apogamy is a related term that has had various meanings over time. In plants with independent gametophytes (notably ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyploidy
Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains one or more chromosomes and comes from each of two parents, resulting in pairs of homologous chromosomes between sets. However, some organisms are polyploid. Polyploidy is especially common in plants. Most eukaryotes have diploid somatic cells, but produce haploid gametes (eggs and sperm) by meiosis. A monoploid has only one set of chromosomes, and the term is usually only applied to cells or organisms that are normally diploid. Males of bees and other Hymenoptera, for example, are monoploid. Unlike animals, plants and multicellular algae have life cycles with two alternating multicellular generations. The gametophyte generation is haploid, and produces gametes by mitosis, the sporophyte generation is diploid and produces spores by mei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sorbus Aria
''Sorbus aria'' ( syn. ''Aria nivea''), the whitebeam or common whitebeam, is a deciduous tree, the type species of the subgenus ''Sorbus'' subg. ''Aria'' of the genus ''Sorbus''. It is native to most of Europe as well as North Africa (Algeria, Morocco, Tunisia) and temperate Asia (Armenia, Georgia). Typically compact and domed, with few upswept branches and almost-white underside of the leaves, it generally favours dry limestone and chalk soils. The hermaphrodite cream-white flowers appear in May, are insect pollinated, and go on to produce scarlet berries, which are often eaten by birds. The cultivars ''S. aria'' 'Lutescens', with very whitish-green early leaves, and ''S. aria'' 'Majestica', with large leaves, have both have gained the Royal Horticultural Society's Award of Garden Merit. The berries are edible when overripe ( bletted). File:Sorbus aria-3420.jpg, Foliage and fruit References aria In music, an aria (Italian: ; plural: ''arie'' , or ''arias'' in commo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens, each chromosome is duplicated ( S phase), and both copies are joined by a centromere, resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. The joined copies are now called si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trends In Ecology And Evolution
A fad or trend is any form of collective behavior that develops within a culture, a generation or social group in which a group of people enthusiastically follow an impulse for a short period. Fads are objects or behaviors that achieve short-lived popularity but fade away. Fads are often seen as sudden, quick-spreading, and short-lived. Fads include diets, clothing, hairstyles, toys, and more. Some popular fads throughout history are toys such as yo-yos, hula hoops, and fad dances such as the Macarena, floss and the twist. Similar to habits or customs but less durable, fads often result from an activity or behavior being perceived as emotionally popular or exciting within a peer group, or being deemed "cool" as often promoted by social networks.Kornblum (2007), p. 213. A fad is said to "catch on" when the number of people adopting it begins to increase to the point of being noteworthy. Fads often fade quickly when the perception of novelty is gone. Overview The specific natu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Ecology (journal)
Molecular ecology is a field of evolutionary biology that is concerned with applying molecular population genetics, molecular phylogenetics, and more recently genomics to traditional ecological questions (e.g., species diagnosis, conservation and assessment of biodiversity, species-area relationships, and many questions in behavioral ecology). It is virtually synonymous with the field of "Ecological Genetics" as pioneered by Theodosius Dobzhansky, E. B. Ford, Godfrey M. Hewitt, and others. These fields are united in their attempt to study genetic-based questions "out in the field" as opposed to the laboratory. Molecular ecology is related to the field of conservation genetics. Methods frequently include using microsatellites to determine gene flow and hybridization between populations. The development of molecular ecology is also closely related to the use of DNA microarrays, which allows for the simultaneous analysis of the expression of thousands of different genes. Quantitat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naturhistoriska Riksmuseet
The Swedish Museum of Natural History ( sv, Naturhistoriska riksmuseet, literally, the National Museum of Natural History), in Stockholm, is one of two major museums of natural history in Sweden, the other one being located in Gothenburg. The museum was founded in 1819 by the Royal Swedish Academy of Sciences, but goes back to the collections acquired mostly through donations by the academy since its foundation in 1739. These collections had first been made available to the public in 1786. The museum was separated from the Academy in 1965. One of the keepers of the collections of the academy during its earlier history was Anders Sparrman, a student of Carl Linnaeus and participant in the voyages of Captain James Cook. Another important name in the history of the museum is the zoologist, paleontologist and archaeologist Sven Nilsson, who brought the previously disorganised zoological collections of the museum into order during his time as keeper (1828–1831) before returning t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rosaceae
Rosaceae (), the rose family, is a medium-sized family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. Among the most species-rich genera are ''Alchemilla'' (270), ''Sorbus'' (260), '' Crataegus'' (260), ''Cotoneaster'' (260), ''Rubus'' (250), and ''Prunus'' (200), which contains the plums, cherries, peaches, apricots, and almonds. However, all of these numbers should be seen as estimates—much taxonomic work remains. The family Rosaceae includes herbs, shrubs, and trees. Most species are deciduous, but some are evergreen. They have a worldwide range but are most diverse in the Northern Hemisphere. Many economically important products come from the Rosaceae, including various edible fruits, such as apples, pears, quinces, apricots, plums, cherries, peaches, raspberries, blackberries, loquats, strawberries, rose hips, hawthorns, and almonds. The family also includes popular ornamental trees and shrubs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
