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Xiphophorus Pygmaeus
''Xiphophorus pygmaeus'', the pygmy swordtail, is a poeciliid fish from northeastern Mexico. It is the smallest of the swordtails. The male's sword is barely visible and the species is often called the swordless swordtail. It is sometimes kept in home aquaria, but is a rather delicate species. Taxonomy and evolution ''Xiphophorus pygmaeus'' is the smallest member of the genus ''Xiphophorus''. It is most closely related to '' X. multilineatus'' and '' X. nigrensis'', and males in particular look similar to the small males of the latter two species. The three species form a clade within the larger clade of northern swordtails. ''X. pygmaeus'' lost large-sized males and male traits associated with larger size: courtship behavior, body depth, and well-developed swords. Large size eventually reappeared in ''X. pygmaeus'' but the normally accompanying traits did not. Description Females grow to , while males attain . The male's sword is only 1-2 mm long. The species was originally thou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Leavitt Hubbs
Carl Leavitt Hubbs (October 19, 1894 – June 30, 1979) was an American ichthyologist. Biography Youth He was born in Williams, Arizona. He was the son of Charles Leavitt and Elizabeth (née Goss) Hubbs. His father had a wide variety of jobs (farmer, iron mine owner, newspaper owner). The family moved several times before settling in San Diego where he got his first taste of natural history. After his parents divorced in 1907, he lived with his mother, who opened a private school in Redondo Beach, California. His maternal grandmother Jane Goble Goss, one of the first female doctors, showed Hubbs how to harvest shellfish and other sea creatures. One of his teachers, impressed by Hubbs's abilities in science, recommended that he study chemistry at the University of Berkeley. The family moved once more to Los Angeles. In Los Angeles, George Bliss Culver, one of the many volunteers of David Starr Jordan, encouraged Hubbs to abandon his study of birds and instead to study fish, par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympatry
In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation. Such speciation may be a product of reproductive isolation – which prevents hybrid offspring from being viable or able to reproduce, thereby reducing gene flow – that results in genetic divergence. Sympatric speciation may, but need not, arise through secondary contact, which refers to speciation or divergence in allopatry followed by range expansions leading to an area of sympatry. Sympatric species or taxa in secondary contact may or may not interbreed. Types of populations Four main types of population pairs exist in nature. Sympatric populations (or species) contrast with parapatric populations, which contact one another in adjacent but not shared ranges and do not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Described In 1943
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods. Most fis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxa Named By Carl Leavitt Hubbs
In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were set forth in Carl Linnaeus's system in ''Systema Naturae'', 10th edition (1758), as well as an unpublished work by Bernard and Antoine Laurent de Jussieu. The idea of a unit-based system of biological classification was first made widely available in 1805 in the intro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infusoria
Infusoria are minute freshwater life forms including ciliates, euglenoids, protozoa, unicellular algae and small invertebrates. Some authors (e.g., Bütschli) used the term as a synonym for Ciliophora. In modern formal classifications, the term is considered obsolete; the microorganisms previously included in the Infusoria are mostly assigned to the kingdom Protista. Aquarium use Infusoria are used by owners of aquaria to feed fish fry; because of its small size it can be used to rear newly hatched fry of many common aquarium species. Many home aquaria are unable to naturally supply sufficient infusoria for fish-rearing, so hobbyists may create and maintain their own supply cultures or use one of the many commercial cultures available.Sharpe, Shirlie (December 22, 2018)"How to Culture Your Own Infusoria at Home" The Spruce Pets. Retrieved August 28, 2019. Infusoria can be cultured by soaking any decomposing vegetative matter such as papaya skin in a jar of aged (i.e., chlorine-fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceratophyllum Demersum
''Ceratophyllum demersum'', commonly known as hornwort, rigid hornwort, coontail, or coon's tail, is a species of ''Ceratophyllum''. It is a submerged, free-floating aquatic plant, with a cosmopolitan distribution, native to all continents except Antarctica. It is a harmful introduced weed in New Zealand.Flora of North America''Ceratophyllum demersum''/ref>Flora of NW Europe''Ceratophyllum demersum''/ref>Blamey, M. & Grey-Wilson, C. (1989). ''Flora of Britain and Northern Europe''. Huxley, A., ed. (1992). ''New RHS Dictionary of Gardening''. Macmillan . It can form turions: buds that sink to the bottom of the water that stay there during the winter and form new plants in spring. Distribution and habitat ''Ceratophyllum demersum'' grows in lakes, ponds, and quiet streams with summer water temperatures of 15-30 °C and a rich nutrient status. In North America, it occurs in the entire US and Canada, except Newfoundland. In Europe, it has been reported as far north as at a latit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquarium
An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquatic reptiles, such as turtles, and aquatic plants. The term ''aquarium'', coined by English naturalist Philip Henry Gosse, combines the Latin root , meaning 'water', with the suffix , meaning 'a place for relating to'. The aquarium principle was fully developed in 1850 by the chemist Robert Warington, who explained that plants added to water in a container would give off enough oxygen to support animals, so long as the numbers of animals did not grow too large. The aquarium craze was launched in early Victorian England by Gosse, who created and stocked the first public aquarium at the London Zoo in 1853, and published the first manual, ''The Aquarium: An Unveiling of the Wonders of the Deep Sea'' in 1854.Katherine C. Grier (2008) "Pet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovoviparity
Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop inside eggs that remain in the mother's body until they are ready to hatch. The young of some ovoviviparous amphibians, such as '' Limnonectes larvaepartus'', are born as larvae, and undergo further metamorphosis outside the body of the mother. Members of genera ''Nectophrynoides'' and ''Eleutherodactylus'' bear froglets, not only the hatching, but all the most conspicuous metamorphosis, being completed inside the body of the mother before birth. Among insects that depend on opportunistic exploitation of transient food sources, such as many Sarcophagidae and other carrion flies, and species such as many Calliphoridae, that rely on fresh dung, and parasitoids such as tachinid flies that depend on entering the host as soon as possible, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copulation
Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetration for sexual pleasure or sexual reproduction; dictionary sources state that it especially means this, and scholarly sources over the years agree. See, for example; * * * * * * * * * This is also known as vaginal intercourse or vaginal sex. Other forms of penetrative sexual intercourse include anal sex (penetration of the anus by the penis), oral sex (penetration of the mouth by the penis or oral penetration of the female genitalia), fingering (sexual penetration by the fingers) and penetration by use of a dildo (especially a strap-on dildo). These activities involve physical intimacy between two or more individuals and are usually used among humans solely for physical or emotional pleasure and can contribute to human bonding. There ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagittaria
''Sagittaria'' is a genus of about 303. Sagittaria Linnaeus ''Flora of North America'' species of aquatic plants whose members go by a variety of common names, including arrowhead, duck potato, katniss, Omodaka (沢瀉 in Japanese), swamp potato, tule potato, and wapato (or wapatoo). Most are native to South America, South, Central America, Central, and North America, but there are also some from Europe, Africa, and Asia. Description Sagittaria plant stock (the perennial rhizome) is a horizontal creeper (stoloniferous) and obliquely obovate, the margins winged, with apical or ventral beak; in other words, they are a small, dry, one-seeded fruit that do not open to release the seed, set on a slant, narrower at the base, with winged edges, and havi ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rio Huichihuayan
Rio or Río is the Portuguese, Spanish, Italian, and Maltese word for "river". When spoken on its own, the word often means Rio de Janeiro, a major city in Brazil. Rio or Río may also refer to: Geography Brazil * Rio de Janeiro * Rio do Sul, a town in the state of Santa Catarina, Brazil Mexico * Río Bec, a Mayan archaeological site in Mexico * Río Bravo, Tamaulipas, a city in Mexico United States * Rio, a location in Deerpark, New York, US * Rio, Florida, a census-designated place in Martin County, US * Rio, Georgia, an unincorporated community in Spalding County, US * Rio, Illinois, a village in Knox County, US * Rio, Virginia, a community in Albemarle County, US * Rio, West Virginia, a village in Hampshire County, US * Rio, Wisconsin, a village in Columbia County, US * El Río, Las Piedras, Puerto Rico, a barrio * Río Arriba, Añasco, Puerto Rico, a barrio * Río Arriba, Arecibo, Puerto Rico, a barrio * Río Arriba, Fajardo, Puerto Rico, a barrio * Río Arriba, Vega Baja, Pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rio Tancuilin
Rio or Río is the Portuguese, Spanish, Italian, and Maltese word for "river". When spoken on its own, the word often means Rio de Janeiro, a major city in Brazil. Rio or Río may also refer to: Geography Brazil * Rio de Janeiro * Rio do Sul, a town in the state of Santa Catarina, Brazil Mexico * Río Bec, a Mayan archaeological site in Mexico * Río Bravo, Tamaulipas, a city in Mexico United States * Rio, a location in Deerpark, New York, US * Rio, Florida, a census-designated place in Martin County, US * Rio, Georgia, an unincorporated community in Spalding County, US * Rio, Illinois, a village in Knox County, US * Rio, Virginia, a community in Albemarle County, US * Rio, West Virginia, a village in Hampshire County, US * Rio, Wisconsin, a village in Columbia County, US * El Río, Las Piedras, Puerto Rico, a barrio * Río Arriba, Añasco, Puerto Rico, a barrio * Río Arriba, Arecibo, Puerto Rico, a barrio * Río Arriba, Fajardo, Puerto Rico, a barrio * Río Arriba, Vega Baja, Pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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