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Axolotls
The axolotl (; from nci, āxōlōtl ), ''Ambystoma mexicanum'', is a paedomorphic salamander closely related to the tiger salamander. Axolotls are unusual among amphibians in that they reach adulthood without undergoing metamorphosis. Instead of taking to the land, adults remain aquatic and gilled. The species was originally found in several lakes underlying what is now Mexico City, such as Lake Xochimilco and Lake Chalco. These lakes were drained by Spanish settlers after the conquest of the Aztec Empire, leading to the destruction of much of the axolotl’s natural habitat. Axolotls should not be confused with the larval stage of the closely related tiger salamander (''A. tigrinum''), which are widespread in much of North America and occasionally become paedomorphic. Neither should they be confused with mudpuppies (''Necturus'' spp.), fully aquatic salamanders from a different family that are not closely related to the axolotl but bear a superficial resemblance. , wild ax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axolotl Ganz
The axolotl (; from nci, āxōlōtl ), ''Ambystoma mexicanum'', is a paedomorphic salamander closely related to the tiger salamander. Axolotls are unusual among amphibians in that they reach adulthood without undergoing metamorphosis. Instead of taking to the land, adults remain aquatic and gilled. The species was originally found in several lakes underlying what is now Mexico City, such as Lake Xochimilco and Lake Chalco. These lakes were drained by Spanish settlers after the conquest of the Aztec Empire, leading to the destruction of much of the axolotl’s natural habitat. Axolotls should not be confused with the larval stage of the closely related tiger salamander (''A. tigrinum''), which are widespread in much of North America and occasionally become paedomorphic. Neither should they be confused with mudpuppies (''Necturus'' spp.), fully aquatic salamanders from a different family that are not closely related to the axolotl but bear a superficial resemblance. , wild ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salamander
Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All ten extant salamander families are grouped together under the order Urodela. Salamander diversity is highest in eastern North America, especially in the Appalachian Mountains; most species are found in the Holarctic realm, with some species present in the Neotropical realm. Salamanders rarely have more than four toes on their front legs and five on their rear legs, but some species have fewer digits and others lack hind limbs. Their permeable skin usually makes them reliant on habitats in or near water or other cool, damp places. Some salamander species are fully aquatic throughout their lives, some take to the water intermittently, and others are entirely terrestrial as adults. This group of amphibians is capable of regenerating lost lim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regeneration (biology)
In biology, regeneration is the process of renewal, restoration, and tissue growth that makes genomes, cells, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage. Every species is capable of regeneration, from bacteria to humans. Regeneration can either be complete where the new tissue is the same as the lost tissue, or incomplete where after the necrotic tissue comes fibrosis. At its most elementary level, regeneration is mediated by the molecular processes of gene regulation and involves the cellular processes of cell proliferation, morphogenesis and cell differentiation. Regeneration in biology, however, mainly refers to the morphogenic processes that characterize the phenotypic plasticity of traits allowing multi-cellular organisms to repair and maintain the integrity of their physiological and morphological states. Above the genetic level, regeneration is fundamentally regulated by asexual cellular processes. Regeneration ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Shaw (biologist)
George Kearsley Shaw (10 December 1751 – 22 July 1813) was an English botanist and zoologist. Life Shaw was born at Bierton, Buckinghamshire, and was educated at Magdalen Hall, Oxford, receiving his M.A. in 1772. He took up the profession of medical practitioner. In 1786 he became the assistant lecturer in botany at the University of Oxford. He was a co-founder of the Linnean Society in 1788, and became a fellow of the Royal Society in 1789. In 1791 Shaw became assistant keeper of the natural history department at the British Museum, succeeding Edward Whitaker Gray as keeper in 1806. He found that most of the items donated to the museum by Hans Sloane were in very bad condition. Medical and anatomical material was sent to the museum at the Royal College of Surgeons, but many of the stuffed animals and birds had deteriorated and had to be burnt. He was succeeded after his death by his assistant Charles Konig. Works Shaw published one of the first English descriptions with s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill Rakers
Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of the gill used for gas exchange. Rakers are usually present in two rows, projecting from both the anterior and posterior side of each gill arch. Rakers are widely varied in number, spacing, and form. By preventing food particles from exiting the spaces between the gill arches, they enable the retention of food particles in filter feeders. The structure and spacing of gill rakers in fish determines the size of food particles trapped, and correlates with feeding behavior. Fish with densely spaced, elongated, comb-like gill rakers are efficient at filtering tiny prey, whereas carnivores and omnivores often have more widely spaced gill rakers with secondary projections. Because gill raker characters often vary between closely related taxa, they are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
External Gills
External gills are the gills of an animal, most typically an amphibian, that are exposed to the environment, rather than set inside the pharynx and covered by gill slits, as they are in most fishes. Instead, the respiratory organs are set on a frill of stalks protruding from the sides of an animal's head. This type of gill is most commonly observed on the aquatic larva of most species of salamanders, lungfish, and bichirs (which have only one large pair), and are retained by neotenic adult salamanders and some species of adult lungfish. They are present on non-transforming salamander species, such as most members of the family Proteidae (the olm and mudpuppies) and the family Sirenidae, which naturally never metamorphose into an air-breathing form. The embryos of frogs and caecilians also develop external gills at some point in their development, though these are either resorbed before or disappear shortly after hatching. Fossils of the distant relatives of modern amphibians, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloaca
In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds, and a few mammals ( monotremes, tenrecs, golden moles, and marsupial moles), have this orifice, from which they excrete both urine and feces; this is in contrast to most placental mammals, which have two or three separate orifices for evacuation. Excretory openings with analogous purpose in some invertebrates are also sometimes referred to as cloacae. Mating through the cloaca is known as cloacal copulation, commonly referred to as cloacal kiss. The cloacal region is also often associated with a secretory organ, the cloacal gland, which has been implicated in the scent-marking behavior of some reptiles, marsupials, amphibians, and monotremes. Etymology The word is from the Latin verb ''cluo'', "(I) cleanse", thus the noun ''cloaca'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yda Addis
Yda Hillis Addis, (born 1857, disappeared 1902 in California, U.S.) was the first American writer to translate ancient Mexican oral stories and histories into English, some of which she submitted to San Francisco-based newspaper ''The Argonaut''. The most widely popular of her more than 100 stories are ''Roman's Romance'' and ''Roger's Luck''. Early life Addis was born in 1857 in Leavenworth, Kansas, and moved with her family to Chihuahua, Mexico, at the start of the American Civil War. The daughter of an itinerant photographer, Alfred Shea Addis, she roamed the Western frontier and Mexican wilderness, into indigenous villages, miners' camps, and other exotic locations, mostly in Mexico and California, assisting her father. When she was 15, Addis and her family moved to Los Angeles, where she graduated with the first class of Los Angeles High School; a graduating class of seven students. She also began teaching seven-year-olds. Career Fiction-writing Addis wrote many short ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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