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Axarus Dorneri
The genus ''Axarus'' is widely distributed with records from the Holarctic, the Neotropics and Australasia . There are currently 5 described nearctic species . Erected as a subgenus (''Anceus'') of ''Xenochironomus'' , ''Axarus'' was subsequently renamed and elevated to generic status . The Connecticut River in the eastern United States harbors locally dense populations of two ''Axarus'' species, both currently undescribed. These populations are interesting in that they are restricted to specific larval habitat ( varve clay and sometimes rotting wood) and thus there is genetic structure between populations in the river . The Connecticut River species are also notable in that they have extremely well developed polytene chromosomes and also maintain a high degree of inversion polymorphism . Species *'' A. dorneri'' ( Malloch, 1915) *'' A. festivus'' Say, 1823 *'' A. rogersi'' (Beck and Beck, 1958) *'' A. scopula'' (Townes, 1945) *'' A. taenionotus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holarctic
The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical region (which covers most of North America), and Alfred Wallace's Palearctic zoogeographical region (which covers North Africa, and all of Eurasia except for Southeast Asia, the Indian subcontinent, the southern Arabian Peninsula). These regions are further subdivided into a variety of ecoregions. Many ecosystems and the animal and plant communities that depend on them extend across a number of continents and cover large portions of the Holarctic realm. This continuity is the result of those regions’ shared glacial history. Major ecosystems Within the Holarctic realm, there are a variety of ecosystems. The type of ecosystem found in a given area depends on its latitude and the local geography. In the far north, a band of Arctic tundra en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymorphism (biology)
In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative ''phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating). Ford E.B. 1965. ''Genetic polymorphism''. Faber & Faber, London. Put simply, polymorphism is when there are two or more possibilities of a trait on a gene. For example, there is more than one possible trait in terms of a jaguar's skin colouring; they can be light morph or dark morph. Due to having more than one possible variation for this gene, it is termed 'polymorphism'. However, if the jaguar has only one possible trait for that gene, it would be termed "monomorphic". For example, if there was only one possible skin colour that a jaguar could have, it would be termed monomorphic. The term polyphenism can be used to clarify that the different forms arise from the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axarus Scopula
The genus ''Axarus'' is widely distributed with records from the Holarctic, the Neotropics and Australasia . There are currently 5 described nearctic species . Erected as a subgenus (''Anceus'') of ''Xenochironomus'' , ''Axarus'' was subsequently renamed and elevated to generic status . The Connecticut River in the eastern United States harbors locally dense populations of two ''Axarus'' species, both currently undescribed. These populations are interesting in that they are restricted to specific larval habitat ( varve clay and sometimes rotting wood) and thus there is genetic structure between populations in the river . The Connecticut River species are also notable in that they have extremely well developed polytene chromosomes and also maintain a high degree of inversion polymorphism . Species *'' A. dorneri'' ( Malloch, 1915) *'' A. festivus'' Say, 1823 *'' A. rogersi'' (Beck and Beck, 1958) *'' A. scopula'' (Townes, 1945) *'' A. taenionotus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axarus Rogersi
The genus ''Axarus'' is widely distributed with records from the Holarctic, the Neotropics and Australasia . There are currently 5 described nearctic species . Erected as a subgenus (''Anceus'') of ''Xenochironomus'' , ''Axarus'' was subsequently renamed and elevated to generic status . The Connecticut River in the eastern United States harbors locally dense populations of two ''Axarus'' species, both currently undescribed. These populations are interesting in that they are restricted to specific larval habitat ( varve clay and sometimes rotting wood) and thus there is genetic structure between populations in the river . The Connecticut River species are also notable in that they have extremely well developed polytene chromosomes and also maintain a high degree of inversion polymorphism . Species *'' A. dorneri'' ( Malloch, 1915) *'' A. festivus'' Say, 1823 *'' A. rogersi'' (Beck and Beck, 1958) *'' A. scopula'' (Townes, 1945) *'' A. taenionotus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Say
Thomas Say (June 27, 1787 – October 10, 1834) was an American entomologist, conchologist, and Herpetology, herpetologist. His studies of insects and shells, numerous contributions to scientific journals, and scientific expeditions to Florida, Georgia, the Rocky Mountains, Mexico, and elsewhere made him an internationally known naturalist. Say has been called the father of American descriptive entomology and American conchology. He served as librarian for the Academy of Natural Sciences of Philadelphia, curator at the American Philosophical Society (elected in 1817), and professor of natural history at the University of Pennsylvania. Early life and education Born in Philadelphia into a prominent Religious Society of Friends, Quaker family, Thomas Say was the great-grandson of John Bartram, and the great-nephew of William Bartram. His father, Dr. Benjamin Say, was brother-in-law to another Bartram son, Moses Bartram. The Say family had a house, "The Cliffs" at Gray's Ferry Bridge, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Russell Malloch
John Russell Malloch (16 November 1875 – 1963) was a Scottish entomologist who specialised in Diptera and Hymenoptera. Malloch was born at Milton of Campsie in Stirlingshire, Scotland. His widowed father had one son, James Malloch (born 1873) when he married John Russell's mother, Margaret Stirling, on 30 August 1875. He and several others of his family worked at a textile factory in the area, but he spent his spare time collecting insects in the fields. His first published paper (1897) describes a type of migrating butterfly. In 1903 Malloch sold his extensive collection to the Glasgow Museum. He continued to collect, but began to concentrate on Diptera from that time forward. Before emigrating in 1910, he donated the remainder of his collection (13,000 flies) to the Royal Scottish Museum. Little is known about Malloch's education. He listed a university degree from Glasgow on his job applications in the USA, but this has not been verified by university records from that area ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axarus Dorneri
The genus ''Axarus'' is widely distributed with records from the Holarctic, the Neotropics and Australasia . There are currently 5 described nearctic species . Erected as a subgenus (''Anceus'') of ''Xenochironomus'' , ''Axarus'' was subsequently renamed and elevated to generic status . The Connecticut River in the eastern United States harbors locally dense populations of two ''Axarus'' species, both currently undescribed. These populations are interesting in that they are restricted to specific larval habitat ( varve clay and sometimes rotting wood) and thus there is genetic structure between populations in the river . The Connecticut River species are also notable in that they have extremely well developed polytene chromosomes and also maintain a high degree of inversion polymorphism . Species *'' A. dorneri'' ( Malloch, 1915) *'' A. festivus'' Say, 1823 *'' A. rogersi'' (Beck and Beck, 1958) *'' A. scopula'' (Townes, 1945) *'' A. taenionotus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northeastern Naturalist
The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A compass rose is primarily composed of four cardinal directions—north, east, south, and west—each separated by 90 degrees, and secondarily divided by four ordinal (intercardinal) directions—northeast, southeast, southwest, and northwest—each located halfway between two cardinal directions. Some disciplines such as meteorology and navigation further divide the compass with additional azimuths. Within European tradition, a fully defined compass has 32 'points' (and any finer subdivisions are described in fractions of points). Compass points are valuable in that they allow a user to refer to a specific azimuth in a colloquial fashion, without having to compute or remember degrees. Designations The names of the compass point directions follow these rules: 8-wind compass rose * The four cardinal directions are north (N), east (E), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Journal Of Zoology
The ''Canadian Journal of Zoology'' is a peer-reviewed scientific journal that covers zoology Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, an .... It was established in 1951 as the continuation of '' Canadian Journal of Research, Section D: Zoological Sciences'', and is associated with the Canadian Society of Zoologists. Abstracting and indexing The journal is abstracted and/or indexed in: References External links {{wikispecies, ISSN 0008-4301 Zoology journals Monthly journals Publications established in 1951 Multilingual journals Canadian Science Publishing academic journals Academic journals associated with learned and professional societies of Canada ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosomal Inversion
An inversion is a chromosome rearrangement in which a segment of a chromosome becomes inverted within its original position. An inversion occurs when a chromosome undergoes a two breaks within the chromosomal arm, and the segment between the two breaks inserts itself in the opposite direction in the same chromosome arm. The breakpoints of inversions often happen in regions of repetitive nucleotides, and the regions may be reused in other inversions. Chromosomal segments in inversions can be as small as 100 kilobases or as large as 100 megabases. The number of genes captured by an inversion can range from a handful of genes to hundreds of genes. Inversions can happen either through ectopic recombination, chromosomal breakage and repair, or non-homologous end joining. Inversions are of two types: paracentric and pericentric. Paracentric inversions do not include the centromere, and both breakpoints occur in one arm of the chromosome. Pericentric inversions span the centromere, and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neotropics
The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropics, tropical Ecoregion#Terrestrial, terrestrial ecoregions of the Americas and the entire South American temperate climate, temperate zone. Definition In biogeography, the Neotropic or Neotropical realm is one of the eight terrestrial realms. This realm includes South America, Central America, the Caribbean islands, and southern North America. In Mexico, the Yucatán Peninsula and southern lowlands, and most of the east and west coastlines, including the southern tip of the Baja California Peninsula are Neotropical. In the United States southern Florida and coastal Central Florida are considered Neotropical. The realm also includes temperate southern South America. In contrast, the Neotropical Phytochorion, Floristic Kingdom excludes southernmost South America, which instead is placed in the Antarctic Floristic Kingdom, Antarctic kingdom. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
