The way we design and build our communities can affect our physical and mental health. Healthy community design integrates evidence-based health strategies into community...
BiodiversityLast Updated on 2014-09-15 23:53:05
The word "biodiversity" is a contracted version of "biological diversity". The Convention on Biological Diversity defines biodiversity as:"the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within species, between species, and of ecosystems."
Thus, biodiversity includes genetic variation within species, the variety of species in an area, and the variety of habitat types within a landscape. Perhaps inevitably, such an all-encompassing definition, together with the strong emotive power of the concept, has led to somewhat cavalier use of the term biodiversity, in extreme cases to refer to life or biology itself. But biodiversity properly refers to the variety of living... More »
AgricultureLast Updated on 2014-09-15 23:44:27Agriculture includes cultivation of crops as tending of livestock for the purpose of production of food and fiber for humans. Mankind began to cultivate food crops about 10,000 years ago. Prior to that time, hunter-gatherers secured their food as they traveled in the nearby environment. When they observed some of the grains left behind at their campsites sprouting and growing to harvest, they began to cultivate these grains. From these humble beginnings agriculture began. Slash and burn, an early type of crop culture, remains today a truly sustainable agriculture, one that is independent of fossil fuel energy. In such a system, about ten hectares of productive land is held in fallow for each planted hectare. With this rotation system, a hectare is planted once every 20 years, allowing the soil to reaccumulate vital plant nutrients. Although the practice requires large acreages and large... More »
SpeciesLast Updated on 2014-09-15 11:53:19A species is a group of organisms capable of interbreeding and producing fertile offspring of both genders, and separated from other such groups with which interbreeding does not characteristically occur: however, for asexual organisms, a distinct species may be considered a collection of organisms which have very similar DNA or physical characteristics. Certain species are further subdivided into subspecies.
The early Greeks and Romans had a well established set of taxonomic names for species of animals and plants, based upon the macroscopically observable characteristics of organisms, with Aristotle being the chief architect of this codification; even earlier, the Egyptians and Cretans developed basic symbols and names for species important in farming and culture. It was not until the year 1686 when English naturalist John Ray introduced the concept that species were... More »
FluorineLast Updated on 2014-09-13 19:14:38Fluorine is a highly reactive chemical element with atomic symbol F. Having the atomic number nine, fluorine is the lightest halogen. Fluorine is a yellow-green gas which does not occur as a free, unreacted element in the natural environment. Under conditions of standard temperature and pressure, elemental fluorine forms a diatomic molecule with chemical formula F2. Chemically, fluorine is one of the strongest known oxidizing agents, and even more reactive and hazardous than chlorine. Its very high electron affinity causes fluorine to react directly with almost all other elements except for several of the Noble gases.
Previous Element: Oxygen
Next Element: Neon
Phase at Room Temp.
Density... More »
Sundarbans National Park, IndiaLast Updated on 2014-09-09 11:56:45
Sundarbans National Park (21°31'-21°53'N, 88°37'-89°09'E) is a World Heritage Site that lies southeast of Calcutta in the 24-Paraganas District of West Bengal and forms part of the Gangetic Delta, which borders on the Bay of Bengal. Consists of Matla, Goashaba, Chhotahardi, Mayadwip, Chamta, Gona and Baghmara forest blocks, which are bounded by the Matla/Bidya and Haribhanga/Raimangal rivers to the east and west, respectively. The northern boundary is buffered by Netidhopani and Chandkhali forest blocks.
Established as a national park on 4 May 1984 (Notification No. 2867-For). Previously created a wildlife sanctuary in 1977, having been designated as the core area of Sundarbans Tiger Reserve in December 1973. All forest in 24-Paraganas District was first notified as protected forest on 7 December 1878. Much of this was subsequently leased out by... More »
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