Monoculture is the agricultural practice of producing or growing a single crop, plant, or livestock species, variety, or breed in a field or farming system at a time. Polyculture, where more than one crop is grown in the same space at the same time, is the alternative to monoculture. Monoculture used both in industrial farming and in organic farming, has allowed increased efficiency in planting and harvesting while increasing the risk of exposure to diseases or pests. Continuous monoculture, or monocropping, where agriculturalists raise the same species year after year, can lead to the quicker buildup of pests and diseases, their rapid spread where a uniform crop is susceptible to a pathogen. Monocultures of perennials, such as African palm oil, sugar cane, pines, can lead to environmental problems. Diversity can be added both in time, as with a crop rotation or sequence, or in space, with a polyculture; the term "oligoculture" has been used to describe a crop rotation of just a few crops, as practiced in several regions of the world.
The concept of monoculture can extend to discussions of variety in urban landscapes. The term describes the practice of planting one species in a field. Examples of monoculture include most fields of wheat or corn; the term is used where a single breed of farm animal is raised in large-scale concentrated animal feeding operations. In crop monocultures, each plant in a field has the same standardized planting and harvesting requirements resulting in greater yields and lower costs; when a crop is matched to its well-managed environment, a monoculture can produce higher yields than a polyculture. In the last 40 years, modern practices such as monoculture planting and the use of synthesized fertilizers have reduced the amount of additional land needed to produce food. Annually planting the same crop in the same area depletes the nutrients from the earth that the plant relies on and leaves soil weak and unable to support healthy growth; because soil structure and quality is so poor, farmers are forced to use chemical fertilizers to encourage plant growth and fruit production.
These fertilizers, in turn, disrupt the natural makeup of the soil and contribute further to nutrient depletion. Polyculture, the mixing of different crops, increases the likelihood that one or more of the crops will be resistant to any particular pathogen. Studies have shown that planting a mixture of crop strains in the same field can combat disease effectively. Switching to polyculture in areas with disease conditions can increased yields. In one study in China, the planting of several varieties of rice in the same field increased yields of non-resistant strains by 89% compared to non-resistant strains grown in monoculture because of a dramatic decrease in the incidence of disease, making pesticides less necessary. Humans rely on a small number of food crops and farm animals for food. If disease hits a major food crop - as happened during the 19th-century Irish potato famine - food supplies for large populations could come under threat. Maintaining and increasing biodiversity in agriculture could help safeguard world food-supplies.
In forestry, monoculture refers to the planting of one species of tree. Monoculture plantings provide greater yields and more efficient harvesting than natural stands of trees. Single-species stands of trees are the natural way trees grow, but the stands show a diversity in tree sizes, with dead trees mixed with mature and young trees. In forestry, monoculture stands that are planted and harvested as a unit provide limited resources for wildlife that depend on dead trees and openings, since all the trees are the same size; the mechanical harvesting of trees can compact soils. Single-species planting causes trees to be more vulnerable when they are infected with a pathogen, or attacked by insects, or affected by adverse environmental conditions. While referring to the mass production of the same species of crop, it can refer to planting of a single cultivar which has same identical genetic makeups to the plants around them; when all plants in a monoculture are genetically similar, a disease, to which they have no resistance, can destroy entire populations of crops.
As of 2009 the wheat leaf-rust fungus occasioned a great deal of worry internationally, having decimated wheat crops in Uganda and Kenya, having started to make inroads into Asia as well. Given the genetically similar strains of much of the world's wheat crops following the Green Revolution, the impacts of such diseases threaten agricultural production worldwide. In Ireland, exclusive use of one variety of potato, the "lumper", led to the Great Famine of 1845-1849. Lumpers provided inexpensive food to feed the Irish masses. Potatoes were propagated vegetatively with little to no genetic variation; when Phytophthora infestans arrived in Ireland from the Americas in 1845, the lumper had no resistance to the disease, leading to the nearly complete failure of the potato crop across Ireland. Until the 1950s, the Gros Michel cultivar of banana represented all bananas consumed in the United States because of their taste, small seeds, efficiency to produce, their small seeds, while more appealing than the large ones in other Asian cultivars, were not suitable for planting.
This meant. As a result of this asexual form of planting, all bananas grown had identical genetic makeups which gave them no traits for resistance to Fusarium wilt, a fungal disease that spread throughout the Caribbe
Limacina helicina is a species of small swimming planktonic sea snail in the family Limacinidae, which belong to the group known as sea butterflies. Limacina helicina is a keystone species of mesozooplankton in Arctic pelagic ecosystems; the first written record of this species was by Friderich Martens from Spitsbergen in 1675. Limacina helicina was observed during a 1773 expedition to the Arctic led by Constantine John Phipps on the ships HMS Racehorse and on HMS Carcass and the species was described one year in 1774. Limacina helicina is the type species of the genus Limacina. In contrast to the traditional view, it was shown in 2010 that the distribution of this species is not bipolar. Limacina helicina helicina Limacina helicina acuta Van Der Spoel, 1967 Limacina helicina ochotensis Shkoldina, 1999 Limacina helicina pacifica Dall, 1871Limacina helicina has been recognised as a species complex comprising two sub-species and at least five forms. In addition, the taxonomic category “forma” has been applied to designate at least three morphotypes of Limacina helicina helicina and two morphotypes of Limacina helicina antarctica.
It is known as Limacina helicina rangii. These forms have different geographical ranges, but it remains unclear as to whether forms represent morphological responses to different environmental conditions or are indeed taxonomically distinct, if the latter, their level of taxonomic separation. However, at the species level the geographical distribution is considered to be bipolar, as it occurs in both the Arctic and Antarctic oceans. Remigio and Hebert provided initial evidence for the genetic separation of Limacina helicina helicina and Limacina helicina antarctica. Hunt et al. have quantified genetic distance within these taxa. Hunt 2010 found a 33.56% difference in cytochrome c oxidase subunit I gene sequences between the "Limacina helicina" which were collected from the Arctic and the Antarctic oceans. This degree of separation is sufficient for ordinal level taxonomic separation in other organisms, provides strong evidence for the Arctic and Antarctic populations of Limacina helicina differing at least at the species level.
Subspecies Limacina helicina antarctica Woodward, 1854 can be considered as a separate species Limacina antarctica Woodward, 1854. A conservative divergence time estimate of 31 Ma for Arctic and Antarctic taxa, indicates that they have undergone rapid independent evolution since the establishment of cold water provinces in the early Oligocene. There is different structure of the shell between Limacina helicina and Limacina antarctica; the type locality of Limacina helicina is "Arctic seas". Limacina helicina is the only thecosome pteropod in Arctic waters; the distribution of Limacina helicina is arctic and subarctic in the Arctic Ocean and countries include: Northern Atlantic Ocean between 50–60 °N, Norwegian Sea, Faroe Islands, North of Iceland Greenland: Denmark Strait and Davis Strait Canada: Anticosti Island, Laurentian Channel, Magdalen Islands, Prince Edward Island, Strait of Belle Isle. USA: area between Cape Hatteras and Newfoundland island. In this species, the color of the soft parts is dark purple or violet, with paler pellucid parapodia.
The shell is sinistral, subdiscoidal and thin. The spire is depressed but it can be considered rather high in comparison of other Limacina species; the shell has 5-6 transversally striated whorls. The suture is distinct; the last whorl is large and with obscure keel next to its umbilicus. The shell has a wide umbilicus; the aperture is higher. The width of the shell is 5 -- up to 13 mm; the height of the shell is up to 6 mm. Adult specimens in the genus Limacina have lost the operculum; the radula consist of 10 rows. Each row consist of two lateral teeth; the Digestive system includes an esophagus, gizzard sac and gut. Pteropods are strict pelagic mollusks that are adapted to life in the open ocean, they are swimming in the water. Limacina helicina is a holoplanktonic species. Habitat of Limacina helicina is upper glacial, it lives in temperatures from -0.4 °C to +4.0 °C or up to 7 °C. Vertical distribution is affected by the size and by other factors. Limacina helicina of the size from 0.2 to 0.4 mm lives in depths from 0 m to 50 m.
Larger pteropods lives from 0 m to 150 m. For example, Gilmer & Harbison have found larger specimen of Limacina helicina to occur in depths 5–25 m with abundance up to 2.5 adults in m3. They do not occur much in upper 4 m because of turbulence. Constantine John Phipps mentioned its "innumerable quantities" in arctic seas in 1774. Limacina helicina is a major component of the polar zooplankton, it can comprise >50% of total zooplankton abundance. Species of the clade Thecosomata produce a fragile external calcium carbonate shell, which could serve as a ballast enabling large vertical migrations and as a protection against predators; the aragonitic composition of the shell makes
Carter Gymnasium is a 947-seat multi-purpose arena in Buies Creek, North Carolina. It was home to the Campbell University Fighting Camels men's basketball and women's basketball teams, it was one of the smallest college basketball venues in Division I. The building was named for textile executive Howard Carter. Built in 1952 and opened in 1953, the dimensions of the basketball court are smaller than regulation, but a grandfather clause allowed Campbell University to continue its tenure in the division; the Fighting Camels began play in 2008 in the new John W. Pope, Jr. Convocation Center; the new $30 million arena seats 3,000 spectators for athletic events. First men's basketball game: February 25, 1953 Loss to Wake Forest College JV 66-63 First women's basketball game: February 25, 1953 Win over Worth's Business College 55-50 First senior college men's basketball game: November 29, 1961, Win over Atlantic Christian College 64-59 February 29, 1964, Angier High School and Boone Trail High School, two Harnett County, North Carolina high schools, played a 13-overtime contest.
Boone Trail won neither team substituted any players. Host venue for 1988 Big South Conference Women's Basketball Tournament