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Western Sand Darter
The western sand darter (''Ammocrypta clara'') is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is native to the central United States. Distribution The western sand darter occurs in river systems from Lake Michigan to Texas, including several sections of the Mississippi Basin. Its range extends as far east as the Elk River in West Virginia. Description This species is up to 7.1 centimeters in length. It is slender and nearly cylindrical in shape. It is pale, translucent silvery white with yellowish coloration along the back. It is distinguished from other sand darters the lack of dark bands or blotches, and by a spine on its operculum. Biology This fish lives in medium and large rivers, over sandy and gravel substrates. It requires loose substrate, because it spends much of its time buried in the sand with just its head protruding. This behavior ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Starr Jordan
David Starr Jordan (January 19, 1851 – September 19, 1931) was the founding president of Stanford University, serving from 1891 to 1913. He was an ichthyologist during his research career. Prior to serving as president of Stanford University, he had served as president of Indiana University from 1884 to 1891. Starr was also a strong supporter of eugenics, and his published views expressed a fear of "race-degeneration" and asserted that cattle and human beings are "governed by the same laws of selection". He was an antimilitarist since he believed that war killed off the best members of the gene pool, and he initially opposed American involvement in World War I. Early life and career Jordan was born in Gainesville, New York, and grew up on a farm in upstate New York. His parents made the unorthodox decision to educate him at a local girls' high school. His middle name, Starr, does not appear in early census records, and was apparently self-selected; he had begun using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operculum (fish)
The operculum is a series of bones found in bony fish and chimaeras that serves as a facial support structure and a protective covering for the gills; it is also used for respiration and feeding. Anatomy The opercular series contains four bone segments known as the preoperculum, suboperculum, interoperculum and operculum. The preoperculum is a crescent-shaped structure that has a series of ridges directed posterodorsally to the organisms canal pores. The preoperculum can be located through an exposed condyle that is present immediately under its ventral margin; it also borders the operculum, suboperculum, and interoperculum posteriorly. The suboperculum is rectangular in shape in most bony fishy and is located ventral to the preoperculum and operculum components. It is the thinnest bone segment out of the opercular series and is located directly above the gills. The interoperculum is triangular shaped and borders the suboperculum posterodorsally and the preoperculum anterodorsa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Fish Of The United States
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include non- salty mineral-rich waters such as chalybeate springs. Fresh water may encompass frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/ sleet and graupel, and surface runoffs that form inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as well as groundwater contained in aquifers, subterranean rivers and lakes. Fresh water is the water resource that is of the most and immediate use to humans. Water is critical to the survival of all living organisms. Many organisms can thrive on salt water, but the great majority of higher plants and most insects, amphibians, reptiles, mammals and birds need fresh water to survive. Fresh wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammocrypta
''Ammocrypta'' is a genus of freshwater ray-finned fish, commonly known as the sand darters, which is classified in the subfamily Etheostomatinae, part of the Family (biology), family Percidae which also includes the perches, Gymnocephalus, ruffes and Sander (fish), pikeperches. The species in the genus occur in eastern North America in Canada and the continental United States. Characteristics ''Ammocrypta'' species are characterised by having rather elongate and slender bodies. Their bodies are translucent and there is only a single spine in the anal fin. They also have Spreitzer vertebrae, that is that the first three vertebrae of the backbone, counting from the head, have an open haemal arch which allows for the fish's kidney to expand. They have the habit of burying into the sand or gravel bed of streams, only their eyes being visible. The translucence of their bodies and their habit of burying themselves gives them some protection against predation. The shared morphological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lock (water Navigation)
A lock is a device used for raising and lowering boats, ships and other watercraft between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is the chamber itself (usually then called a caisson) that rises and falls. Locks are used to make a river more easily navigable, or to allow a canal to cross land that is not level. Later canals used more and larger locks to allow a more direct route to be taken. Pound lock A ''pound lock'' is most commonly used on canals and rivers today. A pound lock has a chamber with gates at both ends that control the level of water in the pound. In contrast, an earlier design with a single gate was known as a flash lock. Pound locks were first used in China during the Song Dynasty (960–1279 AD), having been pioneered by the Song politician and naval ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitat Fragmentation
Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes that slowly alter the layout of the physical environment (suspected of being one of the major causes of speciation), and human activity such as land conversion, which can alter the environment much faster and causes the extinction of many species. More specifically, habitat fragmentation is a process by which large and contiguous habitats get divided into smaller, isolated patches of habitats. Definition The term habitat fragmentation includes five discrete phenomena: * Reduction in the total area of the habitat * Decrease of the interior: edge ratio * Isolation of one habitat fragment from other areas of habitat * Breaking up of one patch of habitat into several smaller patches * Decrease in the average size of each patch of habitat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulnerable Species
A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, threatening its survival and reproduction improve. Vulnerability is mainly caused by habitat loss or destruction of the species' home. Vulnerable habitat or species are monitored and can become increasingly threatened. Some species listed as "vulnerable" may be common in captivity (animal), captivity, an example being the military macaw. There are currently 5196 animals and 6789 plants classified as Vulnerable, compared with 1998 levels of 2815 and 3222, respectively. Practices such as cryoconservation of animal genetic resources have been enforced in efforts to conserve vulnerable breeds of livestock specifically. Criteria The International Union for Conservation of Nature uses several criteria to enter species in this category. A tax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Florida Sand Darter
The Florida sand darter (''Ammocrypta bifascia'') is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to Gulf Coast drainages from the Aplalachicola to the Perdido River in Florida and southern Alabama. It inhabits streams with waters that are clear to tannin-stained where there are shifting sand bottoms and a moderate to fast flow. It is most frequently encountered where there is a moderate current in medium-sized to large streams, but it will enter smaller streams on occasion. Its appearance is identical to the naked sand darter aside from 2 black bands on each dorsal fin. This species can reach a length of , though most are only about in length, at depths of . The Florida sand darter was first formally described in 1975 by James D. Williams with the type locality given as the Choctawhatchee River, west of Pittman, Florida. This species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naked Sand Darter
The naked sand darter (''Ammocrypta beanii'') is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the Family (biology), family Percidae, which also contains the perches, Gymnocephalus, ruffes and Sander (fish), pikeperches. It is found in the south-eastern United States. Description The naked sand darter is a small fish ranging in size from 40 to 50 mm long, the maximum being around 64 mm. Being a long thin darter, it is devoid of scales with the exception of a few rows above and below the lateral line and sometimes the caudal peduncle. Slightly transparent in life with a yellow color and iridescent operculum, the naked sand darter blends in with its habitat. It has darker bands in the dorsal, anal, and caudal fins with a whitish base and tip. Males of breeding size with have a dark spot at the front of the dorsal fin. Unlike similar darters, it does not have an opercular spine. Diet Larvae of small fish are the primary sourc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ottumwa, Iowa
Ottumwa ( ) is a city in and the county seat of Wapello County, Iowa, United States. The population was 25,529 at the time of the 2020 U.S. Census. Located in the state's southeastern section, the city is split into northern and southern halves by the Des Moines River. Ottumwa serves as a major economic, commercial, and cultural hub for the Southeastern Iowa region. Etymology The city's name derives from Native American Sac and Fox, alternatively Meskwaki, language. The English language translation is generally presumed to refer to the Appanoose Rapids of the Des Moines River, as "tumbling waters" or similar. Earlier version of the name were suffixed by the Sac word for place, noc. Alternative translations of the Native American name include: *Place of Perseverance or Self will *Place of Hermits *Place of the lone chief History In May 1843, several investors formed the Appanoose Rapids Company and staked claim to 467 acres of land in the present site of Ottumwa. Their col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Des Moines River
The Des Moines River () is a tributary of the Mississippi River in the upper Midwestern United States that is approximately long from its farther headwaters.U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed May 26, 2011 The largest river flowing across the state of Iowa, it rises in southern Minnesota and flows across Iowa from northwest to southeast, passing from the glaciated plains into the unglaciated hills near the capital city of Des Moines, named after the river, in the center of the state. The river continues to flow at a southeastern direction away from Des Moines, later flowing directly into the Mississippi River. The Des Moines River forms a short portion of Iowa's border with Missouri in Lee County. The Avenue of the Saints, a four-lane highway from St. Paul, Minnesota to St. Louis, Missouri, passes over this section; the highway is designated Route 27 in both Iowa and Missouri, and was completed in the ear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
