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Calyptridium Pulchellum
''Calyptridium pulchellum'', synonym ''Cistanthe pulchella'', is a rare species of flowering plant in the family Montiaceae. It is known by the common name mariposa pussypaws. It is endemic to the Sierra Nevada foothills of central California, where it is known from only a few scattered occurrences. It grows on barren patches of granite gravel in woodland and grasslands. It is a federally listed threatened species. Description It is a very small red-green annual plant radiating spreading stems a few centimeters long. There is a basal rosette of tiny, thick leaves. The inflorescence is a number of spherical clusters of rose-colored petals and thin sepals. The fruit is a tiny translucent capsule containing one or two seeds. Conservation In 2007, there were about 9 or 10 occurrences of the plant, with some occurrences made up of two or more small populations.USFWSMariposa Pussypaws Five-year Review.December 2007. The total population number varies year to year, generally because of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alice Eastwood
__NOTOC__ Alice Eastwood (January 19, 1859 – October 30, 1953) was a Canadian American botanist. She is credited with building the botanical collection at the California Academy of Sciences, in San Francisco. She published over 310 scientific articles and authored 395 land plant species names, the fourth-highest number of such names authored by any female scientist. There are seventeen currently recognized species named for her, as well as the genera ''Eastwoodia'' and '' Aliciella''. Biography Alice Eastwood was born on January 19, 1859, in Toronto, Canada, to Colin Skinner Eastwood and Eliza Jane Gowdey Eastwood. When she was six her mother died. The children were cared for by various relatives, and for a time, Alice and her sister were placed at the Oshawa Convent in Toronto. The family reunited with their father and moved to Denver, Colorado, in 1873. In 1879, she graduated as valedictorian from East Denver High School. For the next ten years, Eastwood would teach at h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subdivision (land)
Subdivisions are the act of dividing land into pieces that are easier to sell or otherwise develop, usually via a plat. The former single piece as a whole is then known as a subdivision. Subdivisions may be simple, involving only a single seller and buyer, or complex, involving large tracts of land divided into many smaller parcels. If it is used for housing it is typically known as a ''housing subdivision'' or ''housing development,'' although some developers tend to call these areas communities. Subdivisions may also be for the purpose of commercial or industrial development, and the results vary from retail shopping malls with independently owned ''out parcels'' to industrial parks. United States History In the United States, the creation of a subdivision was often the first step toward the creation of a new incorporated township or city. Contemporary notions of subdivisions rely on the Lot and Block survey system, which became widely used in the 19th century as a means ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemic Flora Of California
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can be also be referred to as an ''endemism'' or in scientific literature as an ''endemite''. For example '' Cytisus aeolicus'' is an endemite of the Italian flora. '' Adzharia renschi'' was once believed to be an endemite of the Caucasus, but it was later discovered to be a non-indigenous species from South America belonging to a different genus. The extreme opposite of an endemic species is one with a cosmopolitan distribution, having a global or widespread range. A rare alternative term for a species that is endemic is "precinctive", which applies to s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Drift
Genetic drift, also known as allelic drift or the Wright effect, is the change in the frequency of an existing gene variant (allele) in a population due to random chance. Genetic drift may cause gene variants to disappear completely and thereby reduce genetic variation. It can also cause initially rare alleles to become much more frequent and even fixed. When few copies of an allele exist, the effect of genetic drift is more notable, and when many copies exist, the effect is less notable. In the middle of the 20th century, vigorous debates occurred over the relative importance of natural selection versus neutral processes, including genetic drift. Ronald Fisher, who explained natural selection using Mendelian genetics, held the view that genetic drift plays at most a minor role in evolution, and this remained the dominant view for several decades. In 1968, population geneticist Motoo Kimura rekindled the debate with his neutral theory of molecular evolution, which claims that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Bottleneck
A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities such as specicide, widespread violence or intentional culling, and human population planning. Such events can reduce the variation in the gene pool of a population; thereafter, a smaller population, with a smaller genetic diversity, remains to pass on genes to future generations of offspring through sexual reproduction. Genetic diversity remains lower, increasing only when gene flow from another population occurs or very slowly increasing with time as random mutations occur. This results in a reduction in the robustness of the population and in its ability to adapt to and survive natural selection, selecting environmental changes, such as Climate change (general concept), climate change or a shift in available resources. Alternatively, if survivors of the bottleneck are the i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Pathogen
Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Not included are ectoparasites like insects, mites, vertebrate, or other pests that affect plant health by eating plant tissues. Plant pathology also involves the study of pathogen identification, disease etiology, disease cycles, economic impact, plant disease epidemiology, plant disease resistance, how plant diseases affect humans and animals, pathosystem genetics, and management of plant diseases. Overview Control of plant diseases is crucial to the reliable production of food, and it provides significant problems in agricultural use of land, water, fuel and other inputs. Plants in both natural and cultivated populat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drought
A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, and O. Zolina, 2021Water Cycle Changes In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1055–1210, doi:10.1017/9781009157896.010. This means that a drought is "a moisture deficit relative to the average water availability at a given location and season". A drought can last for days, months or years. Drought ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grazing
In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other forages into meat, milk, wool and other animal products, often on land unsuitable for arable farming. Farmers may employ many different strategies of grazing for optimum production: grazing may be continuous, seasonal, or rotational within a grazing period. Longer rotations are found in ley farming, alternating arable and fodder crops; in rest rotation, deferred rotation, and mob grazing, giving grasses a longer time to recover or leaving land fallow. Patch-burn sets up a rotation of fresh grass after burning with two years of rest. Conservation grazing proposes to use grazing animals to improve the biodiversity of a site, but studies show that the greatest benefit to biodiversity comes from removing grazing animals from the landscape. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Livestock
Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animals who are raised for consumption, and sometimes used to refer solely to farmed ruminants, such as cattle, sheep, goats and pigs. Horses are considered livestock in the United States. The USDA classifies pork, veal, beef, and lamb (mutton) as livestock, and all livestock as red meat. Poultry and fish are not included in the category. The breeding, maintenance, slaughter and general subjugation of livestock, called '' animal husbandry'', is a part of modern agriculture and has been practiced in many cultures since humanity's transition to farming from hunter-gatherer lifestyles. Animal husbandry practices have varied widely across cultures and time periods. It continues to play a major economic and cultural role in numerous communities. Lives ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Public Utility
A public utility company (usually just utility) is an organization that maintains the infrastructure for a public service (often also providing a service using that infrastructure). Public utilities are subject to forms of public control and regulation ranging from local community-based groups to statewide government monopolies. Public utilities are meant to supply goods/services that are considered essential; water, gas, electricity, telephone, and other communication systems represent much of the public utility market. The transmission lines used in the transportation of electricity, or natural gas pipelines, have natural monopoly characteristics. If the infrastructure already exists in a given area, minimal benefit is gained through competing. In other words, these industries are characterized by ''economies of scale'' in production. There are many different types of public utilities. Some, especially large companies, offer multiple products, such as electricity and natu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrastructure
Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and private physical structures such as roads, railways, bridges, tunnels, water supply, sewerage, sewers, electrical grids, and telecommunications (including Internet access, Internet connectivity and Broadband, broadband access). In general, infrastructure has been defined as "the physical components of interrelated systems providing Commodity, commodities and services essential to enable, sustain, or enhance societal quality of life, living conditions" and maintain the surrounding environment. Especially in light of the massive societal transformations needed to Climate change mitigation, mitigate and Climate change adaptation, adapt to climate change, contemporary infrastructure conversations frequently focus on sustainable development and gre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Extinction
Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions. Local extinctions mark a change in the ecology of an area. In recent times, local extinction has sometimes been followed by a replacement of the species taken from other locations; wolf reintroduction is an example of this. The term "local extinction" is highly vernacular. The more proper biological term is ''extirpation''. Discussion Glaciation can lead to local extinction. This was the case during the Pleistocene glaciation event in North America. During this period, most of the native North American species of earthworm were killed in places covered by glaciation. This left them open for colonization by European earthworms brought over in soil from Europe. Species naturally become extirpated from islands over time. The number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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