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Cambarus Acuminatus
''Cambarus acuminatus'', the acuminate crayfish, is a species of crayfish in the family Cambaridae. It is found in eastern North America. Taxonomy ''Cambarus acuminatus'' was first described in 1884 by Walter Faxon, then a curator of the Invertebrate Department of the Museum of Comparative Zoology (MCZ) at Harvard University, using specimens collected in 1877 from the Saluda River near Greenville, South Carolina by ichthyologist David Starr Jordan and a student named Alembert Brayton. As was common at the time, Faxon's description was brief, focusing on a few diagnostic characters, and lacked illustrations. Two type specimens were deposited with Butler University, but have since been lost. A syntype, which has disintegrated over time, is held by the MCZ Notable morphological variation between populations of this species have led taxonomists to suggest that crayfish assigned to ''C. acuminatus'' actually form a species complex, ''Cambarus'' sp. C. The lack of detail in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walter Faxon
Walter Faxon (February 4, 1848 – August 10, 1920) was an American ornithologist and carcinologist. He was born at Jamaica Plain, Massachusetts, where he grew up. He received three degrees from Harvard University. One of his greater ornithological achievements was demonstration that Brewster's warbler is a hybrid. He spent many years researching and classifying many American crayfish, including the genera ''Astacus'', ''Orconectes'', and ''Procambarus'', and contributed to at least 20 different scientific papers. Following a 2017 review, carried out by Oxford University, the former ''Faxonius'' subgenus of ''Orconectes'' was raised to a full genus as the subgenera were not monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro .... The genus '' Faxonella'' is similarly named to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species Complex
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each other, further blurring any distinctions. Terms that are sometimes used synonymously but have more precise meanings are cryptic species for two or more species hidden under one species name, sibling species for two (or more) species that are each other's closest relative, and species flock for a group of closely related species that live in the same habitat. As informal taxonomic ranks, species group, species aggregate, macrospecies, and superspecies are also in use. Two or more taxa that were once considered conspecific (of the same species) may later be subdivided into infraspecific taxa (taxa within a species, such as bacterial strains or plant varieties), that is complex but it is not a species complex. A species complex is in most cas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Crustaceans Of North America
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] |
Invasive Species
An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native species that become harmful to their native environment after human alterations to its food webfor example the purple sea urchin (''Strongylocentrotus purpuratus'') which has decimated kelp forests along the northern California coast due to overharvesting of its natural predator, the California sea otter (''Enhydra lutris''). Since the 20th century, invasive species have become a serious economic, social, and environmental threat. Invasion of long-established ecosystems by organisms is a natural phenomenon, but human-facilitated introductions have greatly increased the rate, scale, and geographic range of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procambarus Clarkii
''Procambarus clarkii'', known variously as the red swamp crayfish, Louisiana crawfish or mudbug, is a species of cambarid crayfish native to freshwater bodies of northern Mexico, and southern and southeastern United States, but also introduced elsewhere (both in North America and other continents), where it is often an invasive pest. Appearance ''P. clarkii'' is typically dark red, with long claws and head, small or no spines on the sides of its carapace just below the head, and rows of bright red bumps on the front and side of the first leg. Range and range expansion The native range of ''P. clarkii'' is from northern Mexico and far southeastern New Mexico, through the Gulf States to the Florida Panhandle, as well as inland north through the Mississippi Basin to southern Illinois and Ohio. It has also been introduced, sometimes deliberately, outside its natural range to countries in Asia, Africa, Europe and elsewhere in the Americas. In northern Europe, the populations ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sumter National Forest
The Sumter National Forest is one of two forests in South Carolina that are managed together by the United States Forest Service, the other being the Francis Marion National Forest. The Sumter National Forest consists of which are divided into 3 distinct sections in western and central South Carolina. The Enoree Ranger District is the largest, comprising roughly 170,000 acres in Chester, Fairfield, Laurens, Newberry, and Union counties. Next is the Long Cane Ranger District, comprising about 120,000 acres in Abbeville, Edgefield, Greenwood, McCormick, and Saluda counties. The smallest district is the Andrew Pickens Ranger District comprising over 85,000 acres which lies entirely in Oconee county and is part of the Appalachian Mountains. Forest headquarters of both South Carolina forests are located together in the state's capital city of Columbia. History In July 1936, President Franklin D. Roosevelt proclaimed the Sumter a separate National Forest. The Sumter is named ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitat Destruction
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby reducing biodiversity and species abundance. Habitat destruction is the leading cause of biodiversity loss. Fragmentation and loss of habitat have become one of the most important topics of research in ecology as they are major threats to the survival of endangered species. Activities such as harvesting natural resources, industrial production and urbanization are human contributions to habitat destruction. Pressure from agriculture is the principal human cause. Some others include mining, logging, trawling, and urban sprawl. Habitat destruction is currently considered the primary cause of species extinction worldwide. Environmental factors can contribute to habitat destruction more indirectly. Geological processes, climate change, introdu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riffle-pool Sequence
In a flowing stream, a riffle-pool sequence (also known as a pool-riffle sequence) develops as a stream's hydrological flow structure alternates from areas of relatively shallow to deeper water. This sequence is present only in streams carrying gravel or coarser sediments. Riffles are formed in shallow areas by coarser materials, such as gravel deposits, over which water flows. Pools are deeper, calmer areas whose bed load (in general) is made up of finer material such as silt. Streams with only sand or silt laden beds do not develop the feature. The sequence within a stream bed commonly occurs at intervals of from 5 to 7 stream widths. Meandering streams with relatively coarse bed load tend to develop a riffle-pool sequence with pools in the outsides of the bends and riffles in the ''crossovers'' between one meander A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stream Order
The stream order or waterbody order is a positive whole number used in geomorphology and hydrology to indicate the level of branching in a river system. There are various approachesKoschitzki, 2.3, pp. 12ff to the topological ordering of rivers or sections of rivers based on their distance from the source ("top down"Weishar, p. 30.) or from the confluence (the point where two rivers merge) or river mouth ("bottom up"Weishar, p. 35.), and their hierarchical position within the river system. As terminology, the words "stream" and "branch" tend to be used rather than "river". Classic stream order The ''classic stream order'', also called '' Hack's stream order'' or ''Gravelius' stream order'', is a "bottom up" hierarchy that allocates the number "1" to the river with its mouth at the sea (the main stem). Stream order is an important aspect of a drainage basin. It is defined as the measure of the position of a stream in the hierarchy of streams. Tributaries are given a number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gulf Coastal Plain
The Gulf Coastal Plain extends around the Gulf of Mexico in the Southern United States and eastern Mexico. This coastal plain reaches from the Florida Panhandle, southwest Georgia, the southern two-thirds of Alabama, over most of Mississippi, western Tennessee and Kentucky, into southern Illinois, the Missouri Bootheel, eastern and southern Arkansas, all of Louisiana, the southeast corner of Oklahoma, and easternmost Texas in the United States. It continues along the Gulf in northeastern and eastern Mexico, through Tamaulipas and Veracruz to Tabasco and the Yucatán Peninsula on the Bay of Campeche. Geography The Gulf Coastal Plain's southern boundary is the Gulf of Mexico in the U.S. and the Sierra Madre de Chiapas in Mexico. On the north, it extends to the Ouachita Highlands of the Interior Low Plateaus and the southern Appalachian Mountains. Its northernmost extent is along the Mississippi embayment (Mississippi Alluvial Valley) as far north as the southern tip of Illinois ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piedmont (United States)
The Piedmont is a plateau region located in the Eastern United States. It is situated between the Atlantic coastal plain and the main Appalachian Mountains, stretching from New York in the north to central Alabama in the south. The Piedmont Province is a physiographic province of the larger Appalachian division which consists of the Gettysburg-Newark Lowlands, the Piedmont Upland and the Piedmont Lowlands sections. The Atlantic Seaboard fall line marks the Piedmont's eastern boundary with the Coastal Plain. To the west, it is mostly bounded by the Blue Ridge Mountains, the easternmost range of the main Appalachians. The width of the Piedmont varies, being quite narrow above the Delaware River but nearly 300 miles (475 km) wide in North Carolina. The Piedmont's area is approximately . The French word ''Piedmont'' comes from the it, Piemonte, meaning " foothill", ultimately from Latin "pedemontium", meaning "at the foot of the mountains", similar to the name of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvania
Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, Maryland to its south, West Virginia to its southwest, Ohio to its west, Lake Erie and the Canadian province of Ontario to its northwest, New York to its north, and the Delaware River and New Jersey to its east. Pennsylvania is the fifth-most populous state in the nation with over 13 million residents as of 2020. It is the 33rd-largest state by area and ranks ninth among all states in population density. The southeastern Delaware Valley metropolitan area comprises and surrounds Philadelphia, the state's largest and nation's sixth most populous city. Another 2.37 million reside in Greater Pittsburgh in the southwest, centered around Pittsburgh, the state's second-largest and Western Pennsylvania's largest city. The state's su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
