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Mole Salamanders
The mole salamanders (genus ''Ambystoma'') are a group of Salamandroidea, advanced salamanders endemic to North America. The group has become famous due to the study of the axolotl (''A. mexicanum'') in research on neoteny, paedomorphosis, and the tiger salamander (''A. tigrinum, A. mavortium'') which is often sold as a pet, and is the List of U.S. state amphibians, official amphibian of four US states. General description Terrestrial animal, Terrestrial mole salamanders are identified by having wide, protruding eyes, prominent costal grooves, and thick arms. Most have vivid patterning on dark backgrounds, with marks ranging from deep blue spots to large yellow bars depending on the species. Terrestrial adults spend most of their lives underground in burrows, either of their own making or abandoned by other animals. Some northern species may hibernation, hibernate in these burrows throughout the winter. They live alone and feed on any available invertebrate. Adults spend little ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spotted Salamander
The spotted salamander (''Ambystoma maculatum''), also known commonly as the yellow-spotted salamander, is a species of mole salamander in the family Ambystomatidae. The species is native to the eastern United States and Canada. It is the state amphibian of Ohio and South Carolina. The species ranges from Nova Scotia, to Lake Superior, to southern Georgia and Texas. Its embryos have been found to have symbiotic algae living in and around them, the only known example of vertebrate cells hosting an endosymbiont microbe (unless mitochondria are considered). Description The spotted salamander is about long (tail included), with females generally being larger than males. It is stout, like most mole salamanders, and has a wide snout. The spotted salamander's main color is black, but can sometimes be a bluish-black, dark gray, dark green, or even dark brown. Two uneven rows of yellowish-orange spots run from the top of the head (near the eyes) to the tip of the tail (dorso-late ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill Slit
Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of cartilaginous fish such as sharks and rays, as well as deep-branching vertebrates such as lampreys. In contrast, bony fishes have a single outer bony gill covering called an operculum. Most sharks and rays have five pairs of gill slits, but a few species have 6 or 7 pairs. Shark gill slits lie in a row behind the head. The anterior edge of a gill slit is motile, moving outward to allow water to exit, but closing to prevent reverse flow. A modified slit, called a spiracle, lies just behind the eye, which assists the shark with taking in water during respiration and plays a major role in bottom–dwelling sharks. Spiracles are reduced or missing in active pelagic sharks. While the shark is moving, water passes through the mouth and over the gills in a process known as "ram ventilation". While at rest, most sharks pump water over their gil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genome (journal)
''Genome'', formerly known as the ''Canadian Journal of Genetics and Cytology'' (1959–1986), is a monthly peer-reviewed scientific journal that published since 1959 by NRC Research Press. ''Genome'' prints articles in the fields of genetics and genomics, including cytogenetics, molecular and evolutionary genetics, population genetics, and developmental genetics. ''Genome'' is affiliated with the Canadian Society for Molecular Biosciences, and is co-edited by Melania Cristescu of McGill University and Lewis Lukens of University of Guelph The University of Guelph (abbreviated U of G) is a comprehensive Public university, public research university in Guelph, Ontario, Canada. It was established in 1964 after the amalgamation of Ontario Agricultural College (1874), the MacDonald I .... References External links * Monthly journals Genetics journals Canadian Science Publishing academic journals Multilingual journals Academic journals established in 1959 Genomics j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parthenogenesis
Parthenogenesis (; from the Greek + ) is a natural form of asexual reproduction in which the embryo develops directly from an egg without need for fertilization. In animals, parthenogenesis means the development of an embryo from an unfertilized Gametophyte, egg cell. In plants, parthenogenesis is a component process of apomixis. In algae, parthenogenesis can mean the development of an embryo from either an individual sperm or an individual egg. Parthenogenesis occurs naturally in some plants, algae, invertebrate animal species (including nematodes, some tardigrades, water fleas, some scorpions, aphids, some mites, some bees, some Phasmatodea, and parasitic wasps), and a few vertebrates, such as some fish, amphibians, and reptiles. This type of reproduction has been induced artificially in animal species that naturally reproduce through sex, including fish, amphibians, and mice. Normal egg cells form in the process of meiosis and are haploid, with half as many chromosomes as t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gynogenesis
Gynogenesis, a form of parthenogenesis, is a system of asexual reproduction that requires the presence of sperm without the actual contribution of its DNA for completion. The paternal DNA dissolves or is destroyed before it can fuse with the egg. The egg cell of the organism is able to develop, unfertilized, into an adult using only maternal genetic material. Gynogenesis is often termed "sperm parasitism" in reference to the somewhat pointless role of male gametes. Gynogenetic species, "gynogens" for short, are unisexual, meaning they must mate with males from a closely related bisexual species that normally reproduces sexually. Gynogenesis is a disadvantageous mating system for males, as they are unable to pass on their DNA. The question as to why this reproductive mode exists, given that it appears to combine the disadvantages of both asexual and sexual reproduction, remains unsolved in the field of evolutionary biology. The male equivalent to this process is androgenesis where th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BMC Evolutionary Biology
''BMC Ecology and Evolution'' (since January 2021), previously ''BMC Evolutionary Biology'' (2001–2020), is a peer-reviewed open access scientific journal covering all fields of evolutionary biology, including phylogenetics and palaeontology. It was established in 2001 and is part of a series of BMC journals published by BioMed Central. It was an early journal to integrate with the Dryad Digital Repository to share supplementary data, and it also organises a yearly image competition to help capture the diversity of the planet's flora and fauna. Abstracting and indexing The journal is abstracted and indexed in: According to the ''Journal Citation Reports ''Journal Citation Reports'' (''JCR'') is an annual publication by Clarivate. It has been integrated with the Web of Science and is accessed from the Web of Science Core Collection. It provides information about academic journals in the natur ...'', the journal has a 2020 impact factor of 3.260. References E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plateau Tiger Salamander
The plateau tiger salamander or Mexican tiger salamander (''Ambystoma velasci'') is a species of mole salamander in the family Ambystomatidae. Description The plateau tiger salamander exhibits facultative paedomorphosis. The adult coloration is olive green across the backs with dark spots, and white or cream across the underside of the abdomen. This species has external gills similar to those on other aquatic salamander species. However, this salamander can undergo metamorphosis again in adulthood, via a complex genetic mechanism in response to its environment. During this change, the salamander shrinks, loses its external gills and the legs elongate. Habitat and distribution The plateau tiger salamander is typically considered endemic to Mexico, although its range might extend to the United States. They have a wide geographic distribution, ranging from Chihuahua in the north, to Durango in the south, and to Jalisco in the west. Its natural habitat is grassland, including s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
California Tiger Salamander
The California tiger salamander (''Ambystoma californiense'') is a vulnerable amphibian native to California. It is a mole salamander. Previously considered to be a subspecies of the tiger salamander (''A. tigrinum)'', the California tiger salamander was recently designated a separate species again. Historically, they were endemic to the San Joaquin-Sacramento river valleys, although their range has now contracted into three distinct population segments that are geographically isolated and genetically distinct from one another. The California tiger salamander distinct population segment (DPS) in Sonoma County and the Santa Barbara County DPS are listed as federally endangered, while the Central California DPS is listed as federally threatened. The Sonoma County, south San Joaquin, and the Santa Barbara County DPS have diverged from the rest of the California tiger salamander populations for over one million years, since the Pleistocene and they may warrant status as separate s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barred Tiger Salamander
The barred tiger salamander or western tiger salamander (''Ambystoma mavortium'') is a species of mole salamander that lives in lower western Canada, the western United States and northern Mexico. Description The barred tiger salamander typically grows from , but Neoteny, neotenic forms can grow to lengths of , and is one of the largest species of salamander in North America. It has a broad head and a sturdy body. The color is variable across its range. The dorsal surface is grey, dark brown or black with bars and spots of muddy yellow giving it a tiger-like coloring. The ventral surface varies from light to dark. Larvae have alternating dark and light blotches on the centre of the dorsal surface and pale stripes running along the sides. Kansaspedia states that the tiger salamander has been known to live in captivity for more than 20 years. Behavior Primarily nocturnal animal, nocturnal, barred tiger salamanders are opportunistic feeders, and will often eat anything they can cat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barred Tiger Salamander Tennoji
Barring may refer to: * Barring (music), a guitar playing technique * Barring engine, forms part of the installation of a large stationary steam engine * Barring order, an order used by a court to protect a person, object, business, company, state, country, establishment, or entity, and the general public, in a situation involving alleged domestic violence, child abuse, assault, harassment, stalking, or sexual assault. See also * Bar (other) Bar or BAR may refer to: Food and drink * Bar (establishment), selling alcoholic beverages * Candy bar ** Chocolate bar *Protein bar Science and technology * Bar (river morphology), a deposit of sediment * Bar (tropical cyclone), a layer of ... * Banning {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyroxine
Thyroxine, also known as T4, is a hormone produced by the thyroid gland. It is the primary form of thyroid hormone found in the blood and acts as a prohormone of the more active thyroid hormone, triiodothyronine (T3). Thyroxine and its active metabolites are essential for regulating metabolic rate, supporting heart and muscle function, promoting brain development, and maintaining bone health. Regulation Thyroxine has a half-life of approximately one week and hence maintains relatively stable blood levels. Its production and release are controlled through a complex feedback loop involving the hypothalamus, pituitary gland, and thyroid gland. This regulatory system ensures that optimal hormone levels are maintained. Biosynthesis Thyroxine biosynthesis is a multi-step process that occurs in follicular cell within the thyroid gland. The synthesis of thyroxine requires adequate iodine supply and appropriate hormonal control. The process begins with the active uptake o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neoteny
Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the Physiology, physiological, or Somatic (biology), somatic, development of an organism, typically an animal. Neoteny in humans, Neoteny in modern humans is more significant than in other primates. In progenesis or paedogenesis, sexual development is accelerated. Both neoteny and progenesis result in paedomorphism (as having the form typical of children) or paedomorphosis (changing towards forms typical of children), a type of heterochrony. It is the retention in adults of traits previously seen only in the young. Such retention is important in evolutionary biology, domestication, and evolutionary developmental biology. Some authors define paedomorphism as the retention of larval traits, as seen in salamanders.Schell, S. C. ''Handbook of Trematodes of North America North of Mexico'', 1985, pg. 22 History and etymology Julius Kollmann created the term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
