1.
Coral reef
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Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. Coral reefs are built by colonies of tiny animals found in waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups, the polyps belong to a group of animals known as Cnidaria, which also includes sea anemones and jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons which support, most reefs grow best in warm, shallow, clear, sunny and agitated waters. Often called rainforests of the sea, shallow coral reefs form some of the most diverse ecosystems on Earth, paradoxically, coral reefs flourish even though they are surrounded by ocean waters that provide few nutrients. They are most commonly found at depths in tropical waters. Coral reefs deliver ecosystem services to tourism, fisheries and shoreline protection, the annual global economic value of coral reefs is estimated between US$29. 8-375 billion. However, coral reefs are fragile ecosystems, partly because they are sensitive to water temperature. Most of the coral reefs we can see today were formed after the last glacial period when melting ice caused the sea level to rise and this means that most modern coral reefs are less than 10,000 years old. As communities established themselves on the shelves, the reefs grew upwards, Reefs that rose too slowly could become drowned reefs. They are covered by so much water there was insufficient light. Coral reefs are found in the sea away from continental shelves, around oceanic islands. The vast majority of islands are volcanic in origin. The few exceptions have tectonic origins where plate movements have lifted the deep ocean floor on the surface. In 1842 in his first monograph, The Structure and Distribution of Coral Reefs, Charles Darwin set out his theory of the formation of atoll reefs and he theorized uplift and subsidence of the Earths crust under the oceans formed the atolls. Darwin’s theory sets out a sequence of three stages in atoll formation and it starts with a fringing reef forming around an extinct volcanic island as the island and ocean floor subsides. As the subsidence continues, the reef becomes a barrier reef. Darwin predicted that underneath each lagoon would be a bed rock base, where the level of the underlying earth allows, the corals grow around the coast to form what he called fringing reefs, and can eventually grow out from the shore to become a barrier reef
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Productivity (ecology)
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In ecology, productivity or production refers to the rate of generation of biomass in an ecosystem. It is usually expressed in units of mass per unit surface per unit time, the mass unit may relate to dry matter or to the mass of carbon generated. Productivity of autotrophs such as plants is called primary productivity, while that of such as animals is called secondary productivity. Primary production is the synthesis of new material from inorganic molecules such as H2O. It is dominated by the process of photosynthesis which uses sunlight to synthesise organic molecules such as sugars, organisms responsible for primary production include land plants, marine algae and some bacteria. Secondary production is the generation of biomass of organisms in a system. This is driven by the transfer of material between trophic levels, and represents the quantity of new tissue created through the use of assimilated food. Secondary production is defined to only include consumption of primary producers by herbivorous consumers. Organisms responsible for secondary production include animals, protists, fungi, secondary production can be estimated through a number of different methods including increment summation, removal summation, the instantaneous growth method and the Allen curve method. The choice between these methods will depend on the assumptions of each and the ecosystem under study, for instance, whether cohorts should be distinguished, whether linear mortality can be assumed and whether population growth is exponential
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Marine ecosystem
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Marine ecosystems are among the largest of Earths aquatic ecosystems. Examples include salt marshes, intertidal zones, estuaries, lagoons, mangroves, coral reefs, the sea. They can be contrasted with freshwater ecosystems, which have a salt content. Marine waters cover two-thirds of the surface of the Earth, such places are considered ecosystems because the plant life supports the animal life and vice versa. Marine ecosystems are essential for the health of both marine and terrestrial environments. According to the World Resource Center, coastal habitats account for about one-third of marine biological productivity, estuarine ecosystems, such as salt marshes, seagrass meadows and mangrove forests, are among the most productive ecosystems on the planet. Coral reefs provide food and shelter to the highest levels of diversity in the world. Marine ecosystems usually have a large biodiversity and are thought to have a good resistance against invasive species. However, exceptions have been observed, and the mechanisms responsible in determining the success of an invasion are not yet clear, barange M, Field JG, Harris RP, Eileen E, Hofmann EE, Perry RI and Werner F Marine Ecosystems and Global Change Oxford University Press. ISBN 978-0-19-955802-5 Boyd IL, Wanless S and Camphuysen CJ Top predators in marine ecosystems, their role in monitoring, ISBN 978-0-521-84773-5 Davenport J Challenges to Marine Ecosystems, Proceedings of the 41st European Marine Biology Symposium Volume 202 of Developments in hydrobiology. ISBN 978-1-4020-8807-0 Levner E, Linkov I and Proth J Strategic management of marine ecosystems Springer, Volume 50 of NATO Science Series IV. ISBN 978-1-4020-3158-8 Mann KH and Lazier JRN Dynamics of marine ecosystems, ISBN 978-1-4051-1118-8 Moustakas A and Karakassis I How diverse is aquatic biodiversity research. U. S. Environmental Protection Agency—EPA, Marine Ecosystems Encyclopædia Britannica Online, Marine ecosystem —, smithsonian Institution, Ocean Portal Marine Ecosystems Research Programme
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Temperate rainforest
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Temperate rainforests are coniferous or broadleaf forests that occur in the temperate zone and receive heavy rainfall. For temperate rain forests of North America, Alabacks definition is widely recognized, the North American definition would in turn exclude a part of temperate rain forests in other countries. Temperate forests cover a part of the Earth, but temperate rainforests only occur in a few regions around the world. Jiri and across the southern coastline, southwest Japans Taiheiyo forests, coastal New South Wales. In Eastern North America, there are scattered pockets of temperate rainforest also exist along the Allegheny Plateau and these areas include sections of West Virginia, Western Pennsylvania, as well as Western Upstate New York and the Adirondack Mountains. A good example of these forests are found in Zoar Valley in Upstate New York, Cook Forest State Park within the Allegheny National Forest, like Eastern North America, much precipitation is in the form of rain and snow. In terms of the province system used by botany, the bulk of the region is the Rocky Mountain Floristic Region. They vary in their species composition, but are all predominantly coniferous, sometimes with an understory of broadleaved trees, most of the precipitation occurs in winter but summer fogs moisture is extracted by the trees and produces a fog drip keeping the forest moist. The Northern California coastal forests are home to the Coast Redwood, in the other ecoregions, Coast Douglas-fir, Sitka Spruce, Western Hemlock and Western redcedar are the most important tree species. A common feature of Pacific temperate rain forests of North America is the Nurse log, a fallen tree which as it decays, provides ecological facilitation to seedlings. Trees such as the Coast Douglas-fir, Western Hemlock, Western Red Cedar, Pacific Yew, Some of the largest expanses of old growth are found in Olympic National Park, Mount Rainier National Park, Tongass National Forest, Mount St. These inland rainforests have more continental climate with a proportion of the precipitation falling as snow. Being closer to the Rocky Mountains, there is more of a mammalian fauna. Some of the best interior rain forests are found in Mount Revelstoke National Park, Red spruce and Fraser fir are dominant canopy trees in high mountain areas. In higher elevation, Fraser fir is dominant, in middle elevation red spruce and Fraser fir grow together, below the spruce-fir forest, at around 1,200 metres, are forests of American beech, yellow birch, maple birch, and oak. Skunk cabbage and ground juniper are northern species that were pushed into the areas from the north, the mild and wet environment supports the high diversity of fungi. Over 2000 species live in area and scientists estimate many unidentified fungi may be there. Temperate rain forests occur in the Valdivian temperate rain forests and Magellanic subpolar forests ecoregions, the Valdivian and Magellanic temperate rainforests are the only temperate rain forests in South America
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Olympic Peninsula
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The Olympic Peninsula is the large arm of land in western Washington that lies across Puget Sound from Seattle. It is bounded on the west by the Pacific Ocean, the north by the Strait of Juan de Fuca, Cape Alava, the westernmost point in the contiguous United States, and Cape Flattery, the northwesternmost point, are on the peninsula. Comprising about 3600 square miles, the Olympic Peninsula contained many of the last unexplored places in the contiguous United States and it remained largely unmapped until Arthur Dodwell and Theodore Rixon mapped most of its topography and timber resources between 1898 and 1900. The Olympic Peninsula is home to temperate forests, including the Hoh, Queets Rain Forest. The Olympic mountain range sits in the center of the Olympic Peninsula and this range is the second largest in Washington State. Its highest peak is Mt. Olympus, natural lakes on the peninsula including, Lake Crescent, Lake Ozette, Lake Sutherland, Lake Quinault, and Lake Pleasant. Two dammed rivers form the reservoirs of Lake Cushman and Wynoochee Lake, within the Olympic National Forest, there are five designated wilderness areas, The Brothers, Buckhorn, Colonel Bob, Mt. Skokomish, and Wonder Mountain. Just off the west coast is the Washington Islands Wilderness, clallam and Jefferson Counties, as well as the northern parts of Grays Harbor and Mason Counties, are on the peninsula. The Kitsap Peninsula, bounded by the Hood Canal and the Puget Sound, is an entirely separate peninsula and is not connected to the Olympic Peninsula. From Olympia, the capital, U. S. Route 101 runs along the Olympic Peninsulas southern edge. Most of the peninsula has a climate, or Cfb under the Köppen climate classification. Most populated areas, however, have a warm-summer Mediterranean climate, the Olympic Peninsula is represented in the U. S. House of Representatives by Derek Kilmer
6.
Washington (state)
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It was admitted to the Union as the 42nd state in 1889. Washington is sometimes referred to as Washington State or the State of Washington to distinguish it from Washington, Washington is the 18th largest state with an area of 71,362 square miles, and the 13th most populous state with over 7 million people. Washington is the second most populous state on the West Coast and in the Western United States, Mount Rainier, an active stratovolcano, is the states highest elevation at almost 14,411 feet and is the most topographically prominent mountain in the contiguous United States. Washington is a leading lumber producer and its rugged surface is rich in stands of Douglas fir, hemlock, ponderosa pine, white pine, spruce, larch, and cedar. Manufacturing industries in Washington include aircraft and missiles, shipbuilding and other equipment, lumber, food processing, metals and metal products, chemicals. Washington has over 1,000 dams, including the Grand Coulee Dam, built for a variety of purposes including irrigation, power, flood control, the Washington Territory was named after George Washington, the first President of the United States. The area was part of a region called the Columbia District after the Columbia River. The area was renamed Washington in order to avoid confusion with the District of Columbia, Washington is the only U. S. state named after a president. To distinguish it from the U. S. capital, which is named for George Washington, Washington is sometimes referred to as Washington State, or, in more formal contexts. Washingtonians and other residents of the Pacific Northwest refer to the state simply as Washington, calling the nations capital Washington, D. C. or, often, Washington is the northwestern-most state of the contiguous United States. Washington is bordered by Oregon to the south, with the Columbia River forming the western part, to the west of Washington lies the Pacific Ocean. The high mountains of the Cascade Range run north-south, bisecting the state, from the Cascade Mountains westward, Western Washington has a mostly marine west coast climate, with mild temperatures and wet winters, autumns and springs, and relatively dry summers. The Cascade Range contains several volcanoes, which reach altitudes significantly higher than the rest of the mountains, from the north to the south, these major volcanoes are Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams. Mount Rainier, the tallest mountain in the state, is 50 miles south of the city of Seattle and it is also covered with more glacial ice than any other peak in the contiguous 48 states. Western Washington also is home of the Olympic Mountains, far west on the Olympic Peninsula and these deep forests, such as the Hoh Rainforest, are among the only temperate rainforests in the continental United States. Eastern Washington – the part of the state east of the Cascades – has a dry climate. It includes large areas of steppe and a few truly arid deserts lying in the rain shadow of the Cascades. Farther east, the climate becomes less arid, with annual rainfall increasing as one goes east to 21.2 inches in Pullman, the Okanogan Highlands and the rugged Kettle River Range and Selkirk Mountains cover much of the northeastern quadrant of the state
7.
Community (ecology)
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In ecology, a community or biocoenosis is an assemblage or association of populations of two or more different species occupying the same geographical area and in a particular time. The term community has a variety of uses, in its simplest form it refers to groups of organisms in a specific place or time, for example, the fish community of Lake Ontario before industrialization. The primary focus of community ecology is on the interactions between populations as determined by specific genotypic and phenotypic characteristics, community ecology has its origin in European plant sociology. On a deeper level the meaning and value of the community concept in ecology is up for debate, recently this local community focus has been criticised. Clements developed a concept of community, as it was a superorganism or discrete unit. In that view, it is possible that individualistic distribution of species gives rise to discrete communities as well as to continuum. In the neutral theory view of the community, popularized by Hubbell, species are equivalent. Each population would have the adaptive value, and local and regional composition would represent a balance between speciation or dispersal, and random extinctions. Species interact in ways, competition, predation, parasitism, mutualism, commensalism. The organization of a community with respect to ecological interactions is referred to as community structure. Species can compete each other for finite resources. It is considered to be an important limiting factor of size, biomass. Many types of competition have been described, but proving the existence of interactions is a matter of debate. Direct competition has been observed between individuals, populations and species, but there is evidence that competition has been the driving force in the evolution of large groups. Interference competition, occurs when an individual of one species directly interferes with an individual of another species, examples include a lion chasing a hyena from a kill, or a plant releasing allelopathic chemicals to impede the growth of a competing species. Exploitative competition, This occurs via the consumption of resources, when an individual of one species consumes a resource, that resource is no longer available to be consumed by a member of a second species. The degree of asymmetry has major effects on the structure and diversity of ecological communities Apparent competition. The populations of species can be depressed by predation without direct exploitative competition
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Abiotic component
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In biology and ecology, abiotic components or abiotic factors are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. Abiotic factors and phenomena associated with them underpin all biology, abiotic components include physical conditions and non-living resources that affect living organisms in terms of growth, maintenance, and reproduction. Resources are distinguished as substances or objects in the environment required by one organism, component degradation of a substance occurs by chemical or physical processes, e. g. hydrolysis. All non-living components of an ecosystem, such as the atmosphere or water, are called abiotic components, in biology, abiotic factors can include water, light, radiation, temperature, humidity, atmosphere, and soil. The macroscopic climate often influences each of the above, pressure and sound waves may also be considered in the context of marine or sub-terrestrial environments. All of these factors affect different organisms to different extents, if there is little or no sunlight then plants may wither and die from not being able to get enough sunlight to complete the cycle of photosynthesis. Many Archea require very high temperatures, or pressures, or unusual concentrations of substances, such as sulfur. Certain fungi have evolved to survive mostly at the temperature, the humidity, for example, there is a significant difference in access to water as well as humidity between temperate rain forests and deserts. This difference in water causes a diversity in the types of plants. Biotic component, a part of an ecosystem that affects. Abiogenesis, the transformation of non-living into living matter
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Biotic component
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Biotic components are the living things that shape an ecosystem. Biotic components usually include, Producers, i. e. autotrophs, e. g. plants, consumers, i. e. heterotrophs, e. g. animals, they depend upon producers for food. Decomposers, i. e. detritivores, e. g. fungi and bacteria, a biotic factor is any living component that affects the population of another organism, or the environment. This includes animals that consume the organism, and the food that the organism consumes. Biotic factors also include human influence, pathogens and disease outbreaks, each biotic factor needs energy to do work and food for proper growth. All species are influenced by factors in one way or another. For example, If the number of predators will increase, the food web will be affected. Similarly, when organisms have more food to eat, they will grow quicker and will be likely to reproduce. Pathogens and disease outbreaks, however, are most likely to cause a decrease in population size, humans make the most sudden changes in an environment. These changes are most likely to cause a decrease in the population of any species, biotic components are contrasted to abiotic components, which are non-living components that influence population size and the environment. Examples of abiotic factors are, temperature, light intensity, moisture and water levels, air currents, carbon dioxide levels, the factors mentioned above may either cause an increase or a decrease in population size, depending on the organism. For example, rainfall may encourage the growth of new plants, but too much of it may cause flooding, which may drastically decrease the population size
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Nutrient cycle
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A nutrient cycle is the movement and exchange of organic and inorganic matter back into the production of living matter. The process is regulated by food web pathways that decompose matter into mineral nutrients, ecosystems are interconnected systems where matter and energy flows and is exchanged as organisms feed, digest, and migrate about. Minerals and nutrients accumulate in varied densities and uneven configurations across the planet, particulate matter is recycled by biodiversity inhabiting the detritus in soils, water columns, and along particle surfaces. Ecologists may refer to ecological recycling, organic recycling, biocycling, cycling, biogeochemical recycling, natural recycling, the difference is a matter of scale and compartmentalization with nutrient cycles feeding into global biogeochemical cycles. Solar energy flows through ecosystems along unidirectional and noncyclic pathways, whereas the movement of nutrients is cyclic. Global biogeochemical cycles are the sum product of localized ecological recycling regulated by the action of food webs moving particulate matter from one living generation onto the next, earths ecosystems have recycled mineral nutrients sustainably for billions of years. The nutrient cycle is natures recycling system, all forms of recycling have feedback loops that uses energy in the process of putting material resources back into use. Recycling in ecology is regulated to an extent during the process of decomposition. Ecosystems employ biodiversity in the webs that recycle natural materials, such as mineral nutrients. Recycling in natural systems is one of the ecosystem services that sustain. There is much overlap between the terms for biogeochemical cycle and nutrient cycle, most textbooks integrate the two and seem to treat them as synonymous terms. However, the terms often appear independently, nutrient cycle is more often used in direct reference to the idea of an intra-system cycle, where an ecosystem functions as a unit. From a practical point it does not make sense to assess a terrestrial ecosystem by considering the full column of air above it as well as the depths of Earth below it. While an ecosystem often has no boundary, as a working model it is practical to consider the functional community where the bulk of matter. Nutrient cycling occurs in ecosystems that participate in the biogeochemical cycles of the earth through a system of inputs and outputs. Ecosystems are capable of complete recycling, complete recycling means that 100% of the waste material can be reconstituted indefinitely. This idea was captured by Howard T, despite Georgescu-Roegens extensive intellectual contributions to the science of ecological economics, the fourth law has been rejected in line with observations of ecological recycling. However, some state that complete recycling is impossible for technological waste
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Nitrogen
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Nitrogen is a chemical element with symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772, although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first. Nitrogen is the lightest member of group 15 of the periodic table, the name comes from the Greek πνίγειν to choke, directly referencing nitrogens asphyxiating properties. It is an element in the universe, estimated at about seventh in total abundance in the Milky Way. At standard temperature and pressure, two atoms of the element bind to form dinitrogen, a colourless and odorless diatomic gas with the formula N2, dinitrogen forms about 78% of Earths atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids, in the nucleic acids, the human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes movement of the element from the air, into the biosphere and organic compounds, many industrially important compounds, such as ammonia, nitric acid, organic nitrates, and cyanides, contain nitrogen. The extremely strong bond in elemental nitrogen, the second strongest bond in any diatomic molecule. Synthetically produced ammonia and nitrates are key industrial fertilisers, and fertiliser nitrates are key pollutants in the eutrophication of water systems. Apart from its use in fertilisers and energy-stores, nitrogen is a constituent of organic compounds as diverse as Kevlar used in high-strength fabric, Nitrogen is a constituent of every major pharmacological drug class, including antibiotics. Many notable nitrogen-containing drugs, such as the caffeine and morphine or the synthetic amphetamines. Nitrogen compounds have a long history, ammonium chloride having been known to Herodotus. They were well known by the Middle Ages, alchemists knew nitric acid as aqua fortis, as well as other nitrogen compounds such as ammonium salts and nitrate salts. The mixture of nitric and hydrochloric acids was known as aqua regia, celebrated for its ability to dissolve gold, the discovery of nitrogen is attributed to the Scottish physician Daniel Rutherford in 1772, who called it noxious air. Though he did not recognise it as a different chemical substance, he clearly distinguished it from Joseph Blacks fixed air. The fact that there was a component of air that does not support combustion was clear to Rutherford, Nitrogen was also studied at about the same time by Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley, who referred to it as burnt air or phlogisticated air. Nitrogen gas was inert enough that Antoine Lavoisier referred to it as air or azote, from the Greek word άζωτικός. In an atmosphere of nitrogen, animals died and flames were extinguished
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Sun
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The Sun is the star at the center of the Solar System. It is a perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process. It is by far the most important source of energy for life on Earth. Its diameter is about 109 times that of Earth, and its mass is about 330,000 times that of Earth, accounting for about 99. 86% of the total mass of the Solar System. About three quarters of the Suns mass consists of hydrogen, the rest is mostly helium, with smaller quantities of heavier elements, including oxygen, carbon, neon. The Sun is a G-type main-sequence star based on its spectral class and it formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest flattened into a disk that became the Solar System. The central mass became so hot and dense that it eventually initiated nuclear fusion in its core and it is thought that almost all stars form by this process. The Sun is roughly middle-aged, it has not changed dramatically for more than four billion years and it is calculated that the Sun will become sufficiently large enough to engulf the current orbits of Mercury, Venus, and probably Earth. The enormous effect of the Sun on Earth has been recognized since prehistoric times, the synodic rotation of Earth and its orbit around the Sun are the basis of the solar calendar, which is the predominant calendar in use today. The English proper name Sun developed from Old English sunne and may be related to south, all Germanic terms for the Sun stem from Proto-Germanic *sunnōn. The English weekday name Sunday stems from Old English and is ultimately a result of a Germanic interpretation of Latin dies solis, the Latin name for the Sun, Sol, is not common in general English language use, the adjectival form is the related word solar. The term sol is used by planetary astronomers to refer to the duration of a solar day on another planet. A mean Earth solar day is approximately 24 hours, whereas a mean Martian sol is 24 hours,39 minutes, and 35.244 seconds. From at least the 4th Dynasty of Ancient Egypt, the Sun was worshipped as the god Ra, portrayed as a falcon-headed divinity surmounted by the solar disk, and surrounded by a serpent. In the New Empire period, the Sun became identified with the dung beetle, in the form of the Sun disc Aten, the Sun had a brief resurgence during the Amarna Period when it again became the preeminent, if not only, divinity for the Pharaoh Akhenaton. The Sun is viewed as a goddess in Germanic paganism, Sól/Sunna, in ancient Roman culture, Sunday was the day of the Sun god. It was adopted as the Sabbath day by Christians who did not have a Jewish background, the symbol of light was a pagan device adopted by Christians, and perhaps the most important one that did not come from Jewish traditions
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Photosynthesis
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Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms activities. In most cases, oxygen is released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis, such organisms are called photoautotrophs, in plants, these proteins are held inside organelles called chloroplasts, which are most abundant in leaf cells, while in bacteria they are embedded in the plasma membrane. In these light-dependent reactions, some energy is used to strip electrons from suitable substances, such as water, in the Calvin cycle, atmospheric carbon dioxide is incorporated into already existing organic carbon compounds, such as ribulose bisphosphate. Using the ATP and NADPH produced by the light-dependent reactions, the compounds are then reduced and removed to form further carbohydrates. Cyanobacteria appeared later, the oxygen they produced contributed directly to the oxygenation of the Earth. Today, the rate of energy capture by photosynthesis globally is approximately 130 terawatts. Photosynthetic organisms also convert around 100–115 thousand million tonnes of carbon into biomass per year. Photosynthetic organisms are photoautotrophs, which means that they are able to synthesize food directly from carbon dioxide, however, not all organisms that use light as a source of energy carry out photosynthesis, photoheterotrophs use organic compounds, rather than carbon dioxide, as a source of carbon. In plants, algae, and cyanobacteria, photosynthesis releases oxygen and this is called oxygenic photosynthesis and is by far the most common type of photosynthesis used by living organisms. Although there are differences between oxygenic photosynthesis in plants, algae, and cyanobacteria, the overall process is quite similar in these organisms. There are also varieties of anoxygenic photosynthesis, used mostly by certain types of bacteria. Carbon dioxide is converted into sugars in a process called carbon fixation, photosynthesis provides the energy in the form of free electrons that are used to split carbon from carbon dioxide that is then used to fix that carbon once again as carbohydrate. Carbon fixation is a redox reaction, so photosynthesis supplies the energy that drives both process. In the first stage, light-dependent reactions or light reactions capture the energy of light and use it to make the energy-storage molecules ATP, during the second stage, the light-independent reactions use these products to capture and reduce carbon dioxide. Most organisms that utilize oxygenic photosynthesis use visible light for the light-dependent reactions, some organisms employ even more radical variants of photosynthesis. Some archea use a method that employs a pigment similar to those used for vision in animals. The bacteriorhodopsin changes its configuration in response to sunlight, acting as a proton pump and this produces a proton gradient more directly, which is then converted to chemical energy
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Animal
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Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
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Microorganism
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A microorganism or microbe is a microscopic organism, which may be single-celled or multicellular. The study of microorganisms is called microbiology, a subject that began with the discovery of microorganisms in 1674 by Antonie van Leeuwenhoek, microorganisms are very diverse and include all bacteria, archaea and most protozoa. This group also contains some fungi, algae, and some such as rotifers. Many macroscopic animals and plants have microscopic juvenile stages, some microbiologists classify viruses and viroids as microorganisms, but others consider these as nonliving. In July 2016, scientists identified a set of 355 genes from the last universal ancestor of all life, including microorganisms. Microorganisms, under certain test conditions, have observed to thrive in the vacuum of outer space. Microorganisms likely far outweigh all other living things combined, the mass of prokaryote microorganisms including the bacteria and archaea may be as much as 0.8 trillion tons of carbon, out of the total biomass of between 1 and 4 trillion tons. Microorganisms appear to thrive in the Mariana Trench, the deepest spot in the Earths oceans, in August 2014, scientists confirmed the existence of microorganisms living 800 m below the ice of Antarctica. According to one researcher, You can find microbes everywhere — theyre extremely adaptable to conditions, microorganisms are crucial to nutrient recycling in ecosystems as they act as decomposers. As some microorganisms can fix nitrogen, they are a part of the nitrogen cycle. Microorganisms are also exploited in biotechnology, both in food and beverage preparation, and in modern technologies based on genetic engineering. A small proportion of microorganisms are pathogenic, causing disease and even death in plants, Robert Hooke coined the term cell after viewing plant cells under his microscope. Antonie Van Leeuwenhoek was one of the first people to observe microorganisms in 1673, later, in the 19th century, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In 1876 Robert Koch discovered that microorganisms cause diseases, single-celled microorganisms were the first forms of life to develop on Earth, approximately 3–4 billion years ago. Further evolution was slow, and for about 3 billion years in the Precambrian eon, so, for most of the history of life on Earth, the only forms of life were microorganisms. Bacteria, algae and fungi have been identified in amber that is 220 million years old, microorganisms tend to have a relatively fast rate of evolution. Most microorganisms can reproduce rapidly, and bacteria are able to freely exchange genes through conjugation, transformation and transduction. This rapid evolution is important in medicine, as it has led to the development of multidrug resistant pathogenic bacteria, superbugs, the possible existence of microorganisms was discussed for many centuries before their discovery in the 17th century
16.
Biomass (ecology)
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Biomass, is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to species biomass, which is the mass of one or more species, or to community biomass and it can include microorganisms, plants or animals. The mass can be expressed as the mass per unit area. How biomass is measured depends on why it is being measured, sometimes, the biomass is regarded as the natural mass of organisms in situ, just as they are. For example, in a fishery, the salmon biomass might be regarded as the total wet weight the salmon would have if they were taken out of the water. In other contexts, biomass can be measured in terms of the organic mass, so perhaps only 30% of the actual weight might count. For other purposes, only biological tissues count, and teeth, bones, in some applications, biomass is measured as the mass of organically bound carbon that is present. Apart from bacteria, the total biomass on Earth is about 560 billion tonnes C. The total live biomass of bacteria may be as much as that of plants, the total amount of DNA base pairs on Earth, as a possible approximation of global biodiversity, is estimated at 5.0 x 1037, and weighs 50 billion tonnes. In comparison, the mass of the biosphere has been estimated to be as much as 4 TtC. An ecological pyramid is a representation that shows, for a given ecosystem. A biomass pyramid shows the amount of biomass at each trophic level, a productivity pyramid shows the production or turn-over in biomass at each trophic level. An ecological pyramid provides a snapshot in time of an ecological community, the bottom of the pyramid represents the primary producers. The primary producers take energy from the environment in the form of sunlight or inorganic chemicals and this mechanism is called primary production. The pyramid then proceeds through the trophic levels to the apex predators at the top. When energy is transferred from one level to the next. The remaining ninety percent goes to metabolic processes or is dissipated as heat and this energy loss means that productivity pyramids are never inverted, and generally limits food chains to about six levels. However, in oceans, biomass pyramids can be wholly or partially inverted, terrestrial biomass generally decreases markedly at each higher trophic level
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Climate
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Climate is the statistics of weather, usually over a 30-year interval. Climate differs from weather, in that weather only describes the conditions of these variables in a given region. A regions climate is generated by the system, which has five components, atmosphere, hydrosphere, cryosphere, lithosphere. The climate of a location is affected by its latitude, terrain, climates can be classified according to the average and the typical ranges of different variables, most commonly temperature and precipitation. The most commonly used classification scheme was the Köppen climate classification, the Bergeron and Spatial Synoptic Classification systems focus on the origin of air masses that define the climate of a region. Paleoclimatology is the study of ancient climates, Climate models are mathematical models of past, present and future climates. Climate change may occur long and short timescales from a variety of factors. For example, a 3°C change in mean annual temperature corresponds to a shift in isotherms of approximately 300–400 km in latitude or 500 m in elevation, therefore, species are expected to move upwards in elevation or towards the poles in latitude in response to shifting climate zones. Climate is commonly defined as the weather averaged over a long period, the standard averaging period is 30 years, but other periods may be used depending on the purpose. Climate also includes statistics other than the average, such as the magnitudes of day-to-day or year-to-year variations, the classical period is 30 years, as defined by the World Meteorological Organization. These quantities are most often surface variables such as temperature, precipitation, Climate in a wider sense is the state, including a statistical description, of the climate system. The World Meteorological Organization describes climate normals as reference points used by climatologists to compare current climatological trends to that of the past or what is considered normal, a Normal is defined as the arithmetic average of a climate element over a 30-year period. A30 year period is used, as it is enough to filter out any interannual variation or anomalies. The WMO originated from the International Meteorological Organization which set up a commission for climatology in 1929. At its 1934 Wiesbaden meeting the commission designated the thirty-year period from 1901 to 1930 as the reference time frame for climatological standard normals. In 1982 the WMO agreed to update climate normals, and in these were completed on the basis of climate data from 1 January 1961 to 31 December 1990. The difference between climate and weather is usefully summarized by the popular phrase Climate is what you expect, weather is what you get. Over historical time spans there are a number of nearly constant variables that determine climate, including latitude, altitude, proportion of land to water and these change only over periods of millions of years due to processes such as plate tectonics
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Topography
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Topography is the study of the shape and features of the surface of the Earth and other observable astronomical objects including planets, moons, and asteroids. The topography of an area could refer to the shapes and features themselves. This field of geoscience and planetary science is concerned with detail in general, including not only relief but also natural and artificial features. This meaning is common in the United States, where topographic maps with elevation contours have made topography synonymous with relief. The older sense of topography as the study of place still has currency in Europe, topography in a narrow sense involves the recording of relief or terrain, the three-dimensional quality of the surface, and the identification of specific landforms. This is also known as geomorphometry, in modern usage, this involves generation of elevation data in digital form. It is often considered to include the representation of the landform on a map by a variety of techniques, including contour lines, hypsometric tints. The term topography originated in ancient Greece and continued in ancient Rome, the word comes from the Greek τόπος and -γραφία. In classical literature this refers to writing about a place or places, in Britain and in Europe in general, the word topography is still sometimes used in its original sense. Detailed military surveys in Britain were called Ordnance Surveys, and this term was used into the 20th century as generic for topographic surveys, the earliest scientific surveys in France were called the Cassini maps after the family who produced them over four generations. The term topographic surveys appears to be American in origin, the earliest detailed surveys in the United States were made by the “Topographical Bureau of the Army, ” formed during the War of 1812, which became the Corps of Topographical Engineers in 1838. In the 20th century, the term started to be used to describe surface description in other fields where mapping in a broader sense is used. An objective of topography is to determine the position of any feature or more generally any point in terms of both a horizontal coordinate system such as latitude, longitude, and altitude, identifying features, and recognizing typical landform patterns are also part of the field. There are a variety of approaches to studying topography, which method to use depend on the scale and size of the area under study, its accessibility, and the quality of existing surveys. Work on one of the first topographic maps was begun in France by Giovanni Domenico Cassini, in areas where there has been an extensive direct survey and mapping program, the compiled data forms the basis of basic digital elevation datasets such as USGS DEM data. This data must often be cleaned to eliminate discrepancies between surveys, but it forms a valuable set of information for large-scale analysis. The original American topographic surveys involved not only recording of relief, remote sensing is a general term for geodata collection at a distance from the subject area. Besides their role in photogrammetry, aerial and satellite imagery can be used to identify and delineate terrain features, certainly they have become more and more a part of geovisualization, whether maps or GIS systems
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Disturbance (ecology)
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In biology, a disturbance is a temporary change in environmental conditions that causes a pronounced change in an ecosystem. Disturbances often act quickly and with effect, to alter the physical structure or arrangement of biotic and abiotic elements. Disturbance can also occur over a period of time and can impact the diversity within an ecosystem. Major ecological disturbances may include fires, flooding, windstorms, insect outbreaks, Disturbance forces can have profound immediate effects on ecosystems and can, accordingly, greatly alter the natural community. Conditions under which natural disturbances occur are influenced mainly by climate, weather, fire disturbances will only occur in areas where there is low precipitation, some form of ignition, and enough flammable biomass to allow fire to spread. Conditions often occur as part of a cycle and disturbances may be periodic, other disturbances, such as those caused by humans, invasive species or impact events, can occur anywhere and are not necessarily cyclic. Extinction vortices may result in multiple disturbances or a frequency of a single disturbance. Immediately after a disturbance there is a pulse of recruitment or regrowth under conditions of competition for space or other resources. After the initial pulse, recruitment slows since once a plant is established it is very difficult to displace. Due to the forms of disturbance this directly impacts the organisms which will exploit the disturbance. Often, when disturbances occur naturally, they provide conditions that favor the success of different species over pre-disturbance organisms and this can be attributed to physical changes in the biotic and abiotic conditions of an ecosystem. Because of this, a force can change an ecosystem for significantly longer than the period over which the immediate effects persist. With the passage of time following a disturbance, shifts in dominance may occur with ephemeral herbaceous life-forms progressively becoming over topped by taller perennials herbs, shrubs, however, in the absence of further disturbance forces, many ecosystems trend back toward pre-disturbance conditions. Long lived species and those that can regenerate in the presence of their own adults finally become dominant, such alteration, accompanied by changes in the abundance of different species over time, is called ecological succession. Succession often leads to conditions that will once again predispose an ecosystem to disturbance, Pine forests in the western North America provide a good example of such a cycle involving insect outbreaks. The mountain pine beetle play an important role in limiting pine trees like lodgepole pine in forests of western North America, in 2004 the beetles affected more than 90,000 square kilometres. The beetles exist in endemic and epidemic phases, during epidemic phases swarms of beetles kill large numbers of old pines. This mortality creates openings in the forest for new vegetation, spruce, fir, and younger pines, which are unaffected by the beetles, thrive in canopy openings
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Feedback
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Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to feed back into itself and this makes reasoning based upon cause and effect tricky, and it is necessary to analyze the system as a whole. This action of feeding back of the signal output to input gave rise to the use of the term feedback as a distinct word by 1920. Over the years there has been dispute as to the best definition of feedback. According to Ashby, mathematicians and theorists interested in the principles of feedback mechanisms prefer the definition of circularity of action, for those with more practical aims, feedback should be a deliberate effect via some more tangible connection. Object to the definition, pointing out that this would force them to say that feedback was present in the ordinary pendulum. Between its position and its momentum—a feedback that, from the point of view, is somewhat mystical. He emphasizes that the information by itself is not feedback unless translated into action, there are two types of feedback, positive feedback and negative feedback. As an example of feedback, the diagram might represent a cruise control system in a car, for example. The controlled system is the car, its input includes the combined torque from the engine, the cars speed is measured by a speedometer. The error signal is the departure of the speed as measured by the speedometer from the target speed and this measured error is interpreted by the controller to adjust the accelerator, commanding the fuel flow to the engine. The resulting change in torque, the feedback, combines with the torque exerted by the changing road grade to reduce the error in speed. The terms positive and negative were first applied to prior to WWII. The idea of positive feedback was already current in the 1920s with the introduction of the regenerative circuit, harold Stephen Blacks classic 1934 paper first details the use of negative feedback in electronic amplifiers. According to Black, Positive feed-back increases the gain of the amplifier, according to Mindell confusion in the terms arose shortly after this. In contrast, Nyquist and Bode, when built on Black’s work. Black had trouble convincing others of the utility of his invention in part because confusion existed over basic matters of definition, the terms positive and negative feedback are defined in different ways within different disciplines. The altering of the gap between reference and actual values of a parameter, based on whether the gap is widening or narrowing
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Human
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Modern humans are the only extant members of Hominina tribe, a branch of the tribe Hominini belonging to the family of great apes. Several of these hominins used fire, occupied much of Eurasia and they began to exhibit evidence of behavioral modernity around 50,000 years ago. In several waves of migration, anatomically modern humans ventured out of Africa, the spread of humans and their large and increasing population has had a profound impact on large areas of the environment and millions of native species worldwide. Humans are uniquely adept at utilizing systems of communication for self-expression and the exchange of ideas. Humans create complex structures composed of many cooperating and competing groups, from families. Social interactions between humans have established a wide variety of values, social norms, and rituals. These human societies subsequently expanded in size, establishing various forms of government, religion, today the global human population is estimated by the United Nations to be near 7.5 billion. In common usage, the word generally refers to the only extant species of the genus Homo—anatomically and behaviorally modern Homo sapiens. In scientific terms, the meanings of hominid and hominin have changed during the recent decades with advances in the discovery, there is also a distinction between anatomically modern humans and Archaic Homo sapiens, the earliest fossil members of the species. The English adjective human is a Middle English loanword from Old French humain, ultimately from Latin hūmānus, the words use as a noun dates to the 16th century. The native English term man can refer to the species generally, the species binomial Homo sapiens was coined by Carl Linnaeus in his 18th century work Systema Naturae. The generic name Homo is a learned 18th century derivation from Latin homō man, the species-name sapiens means wise or sapient. Note that the Latin word homo refers to humans of either gender, the genus Homo evolved and diverged from other hominins in Africa, after the human clade split from the chimpanzee lineage of the hominids branch of the primates. The closest living relatives of humans are chimpanzees and gorillas, with the sequencing of both the human and chimpanzee genome, current estimates of similarity between human and chimpanzee DNA sequences range between 95% and 99%. The gibbons and orangutans were the first groups to split from the leading to the humans. The splitting date between human and chimpanzee lineages is placed around 4–8 million years ago during the late Miocene epoch, during this split, chromosome 2 was formed from two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. There is little evidence for the divergence of the gorilla, chimpanzee. Each of these species has been argued to be an ancestor of later hominins
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Global warming
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Global warming and climate change are terms for the observed century-scale rise in the average temperature of the Earths climate system and its related effects. Multiple lines of evidence show that the climate system is warming. The largest human influence has been emission of gases such as carbon dioxide, methane. These findings have been recognized by the science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing. Future climate change and associated impacts will differ from region to region around the globe, anticipated effects include warming global temperature, rising sea levels, changing precipitation, and expansion of deserts in the subtropics. Warming is expected to be greater over land than over the oceans and greatest in the Arctic, with the retreat of glaciers, permafrost. Effects significant to humans include the threat to security from decreasing crop yields. Possible societal responses to global warming include mitigation by emissions reduction, adaptation to its effects, building systems resilient to its effects, most countries are parties to the United Nations Framework Convention on Climate Change, whose ultimate objective is to prevent dangerous anthropogenic climate change. Public reactions to global warming and concern about its effects are also increasing, a global 2015 Pew Research Center report showed a median of 54% consider it a very serious problem. There are significant regional differences, with Americans and Chinese among the least concerned, the global average surface temperature shows a warming of 0.85 °C in the period 1880 to 2012, based on multiple independently produced datasets. Earths average surface temperature rose by 0. 74±0.18 °C over the period 1906–2005, the rate of warming almost doubled for the last half of that period. The rest has melted ice and warmed the continents and atmosphere, the average temperature of the lower troposphere has increased between 0.12 and 0.135 °C per decade since 1979, according to satellite temperature measurements. The warming that is evident in the temperature record is consistent with a wide range of observations. The probability that these changes could have occurred by chance is virtually zero, temperature changes vary over the globe. Since 1979, land temperatures have increased about twice as fast as ocean temperatures, ocean temperatures increase more slowly than land temperatures because of the larger effective heat capacity of the oceans and because the ocean loses more heat by evaporation. Since the beginning of industrialisation the temperature difference between the hemispheres has increased due to melting of sea ice and snow in the North. Average arctic temperatures have been increasing at almost twice the rate of the rest of the world in the past 100 years, the thermal inertia of the oceans and slow responses of other indirect effects mean that climate can take centuries or longer to adjust to changes in forcing. Some of this warming will be driven by past natural forcings which are still seeking equilibrium in the climate system
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Ecosystem services
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Humankind benefits in a multitude of ways from all kinds of ecosystems, agroecosystemss, forest ecosystems, grassland ecosystems, aquatic ecosystems, natural ecosystems, urban ecosystems, etc. Collectively, these benefits are becoming known as ecosystem services, Ecosystem services are regularly involved in the provisioning of clean drinking water and the decomposition of wastes. While scientists and environmentalists have discussed ecosystem services implicitly for decades, to help inform decision-makers, many ecosystem services are being assigned economic values. Recognition of how ecosystems could provide services to humankind date back to at least Plato who understood that deforestation could lead to soil erosion. Modern ideas of ecosystem services probably began when Marsh challenged in 1864 the idea that Earth’s natural resources are unbounded by pointing out changes in fertility in the Mediterranean. It was not until the late 1940s that three key authors – Henry Fairfield Osborn, Jr, William Vogt, and Aldo Leopold – promoted recognition of human dependence on the environment. In 1956, Paul Sears drew attention to the role of the ecosystem in processing wastes. In 1970, Paul Ehrlich and Rosa Weigert called attention to ecological systems in their environmental science textbook, the potential destruction, by man’s own activities, of those ecological systems upon which the very existence of the human species depends. In following years, variations of the term were used, the ecosystem services concept has continued to expand and includes socio-economic and conservation objectives, which are discussed below. A history of the concepts and terminology of ecosystem services as of 1997, can be found in Dailys book Nature’s Services, per the 2006 Millennium Ecosystem Assessment, ecosystem services are the benefits people obtain from ecosystems. The MA also delineated the four categories of ecosystem services—supporting, provisioning, regulating, by 2010, there had evolved various working definitions and descriptions of ecosystem services in the literature. Ecosystem services that are necessary for the production of all other ecosystem services and these include services such as nutrient recycling, primary production and soil formation. These services make it possible for the ecosystems to provide such as food supply, flood regulation. Who vote for models that explicitly link ecological structures and functions with cultural values and those cultural values do result not from properties produced by ecosystems but are the product of a specific way of seeing within the given cultural framework of symbolic experience. S. Environmental Protection Agency, authorities opted to restore the polluted Catskill Watershed that had provided the city with the ecosystem service of water purification. Pollination of crops by bees is required for 15-30% of U. S. food production, however, intensified agricultural practices can quickly erode pollination services through the loss of species. The remaining species are unable to compensate this, the presence of such ecosystem elements functions almost like an insurance policy for farmers. In watersheds of the Yangtze River, spatial models for water flow through different forest habitats were created to determine potential contributions for hydroelectric power in the region, in the 1980s, mineral water company Vittel faced a critical problem
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Ecosystem management
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The principal objective of ecosystem management is the efficient maintenance and ethical use of natural resources. It is a multifaceted and holistic approach which requires a significant change in how the natural, the definitions of ecosystem management are typically vague. These assertions are important to understanding much of the surrounding ecosystem management. The complex nature of decisions made in management, from local to international scales, requires stakeholder participation from a diversity of knowledge, perceptions. Stakeholders will often have different interests in ecosystem services and this means effective management of ecosystems requires a negotiation process that develops mutual trust in issues of common interest with the objective of creating mutually beneficial partnerships. Adaptive management is based on the concept that predicting future influences/disturbance to an ecosystem is limited, Adaptive management aims to identify uncertainties in the management of an ecosystem while using hypothesis testing to further understand the system. In this regard, adaptive management encourages learning from the outcomes of previously implemented management strategies, Ecosystem managers form hypotheses about the ecosystem and its functionality and then implement different management techniques to test the hypotheses. The implemented techniques are then analyzed to evaluate any regressions or improvements in functionality of the caused by the technique. Further analysis allows for modification of the technique until it meets the ecological needs of the ecosystem. Thus, adaptive management serves as a “learning by doing” method for ecosystem management, additionally, economic, social and political priorities can interfere with adaptive management decisions. For this reason, adaptive management should be a process as well as scientific. The term natural resource management is used when dealing with a particular resource for human use rather than managing the whole ecosystem. The balanced relationship of each resource in an ecosystem is subject to change at different spatial and temporal scales, dimensions such as, watersheds, soils, flora and fauna, need to be considered individually and on a landscape level. A variety of resources are utilized for food, medicine, energy. The ecosystem management concept is based on the relationship between sustainable resource maintenance and human demand for use of natural resources, therefore, socioeconomics factors significantly affect natural resource management. The goal of a resource manager is to fulfill the demand for a given resource without causing harm to the ecosystem. Partnerships between ecosystem managers, natural resource managers and stakeholders should be encouraged in order to promote a sustainable use of limited natural resources. Natural resource managers must initially measure the integrity of the ecosystem they are involved in
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Species
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In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
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Drainage basin
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A drainage basin or catchment area is any area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water. Drainage basins connect into other drainage basins at elevations in a hierarchical pattern, with smaller sub-drainage basins. Other terms used to describe drainage basins are catchment, catchment basin, drainage area, river basin and water basin. In closed drainage basins the water converges to a point inside the basin, known as a sink, which may be a permanent lake. The drainage basin acts as a funnel by collecting all the water within the covered by the basin. Each drainage basin is separated topographically from adjacent basins by a perimeter, drainage basins are similar but not identical to hydrologic units, which are drainage areas delineated so as to nest into a multi-level hierarchical drainage system. Hydrologic units are defined to allow multiple inlets, outlets, or sinks, in a strict sense, all drainage basins are hydrologic units but not all hydrologic units are drainage basins. Drainage basins of the oceans and seas of the world. Grey areas are endorheic basins that do not drain to the oceans, the following is a list of the major ocean basins, About 48. 7% of the worlds land drains to the Atlantic Ocean. The two major mediterranean seas of the world also flow to the Atlantic, The Caribbean Sea and Gulf of Mexico basin includes most of the U. S. The Mediterranean Sea basin includes much of North Africa, east-central Africa, Southern, Central, and Eastern Europe, Turkey, and the areas of Israel, Lebanon. Just over 13% of the land in the world drains to the Pacific Ocean, the Indian Oceans drainage basin also comprises about 13% of Earths land. It drains the eastern coast of Africa, the coasts of the Red Sea and the Persian Gulf, the Indian subcontinent, Burma, antarctica comprises approximately eight percent of the Earths land. The five largest river basins, from largest to smallest, are the basins of the Amazon, the Río de la Plata, the Congo, the Nile, and the Mississippi. The three rivers that drain the most water, from most to least, are the Amazon, Ganga, endorheic drainage basins are inland basins that do not drain to an ocean. Around 18% of all land drains to endorheic lakes or seas or sinks, the largest of these consists of much of the interior of Asia, which drains into the Caspian Sea, the Aral Sea, and numerous smaller lakes. Some of these, such as the Great Basin, are not single drainage basins but collections of separate, in endorheic bodies of standing water where evaporation is the primary means of water loss, the water is typically more saline than the oceans. An extreme example of this is the Dead Sea, drainage basins have been historically important for determining territorial boundaries, particularly in regions where trade by water has been important
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Ecosystem ecology
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Ecosystem ecology is the integrated study of living and non-living components of ecosystems and their interactions within an ecosystem framework. This science examines how ecosystems work and relates this to their components such as chemicals, bedrock, soil, plants, ecosystem ecology examines physical and biological structures and examines how these ecosystem characteristics interact with each other. Ultimately, this helps us understand how to high quality water. A major focus of ecosystem ecology is on functional processes, ecological mechanisms that maintain the structure and these include primary productivity, decomposition, and trophic interactions. Studies of ecosystem function have greatly improved understanding of sustainable production of forage, fiber, fuel. Functional processes are mediated by regional-to-local level climate, disturbance, will timber cutting in the forest degrade recreational fishing in the stream. These questions are difficult for managers to address while the boundary between ecosystems remains unclear, even though decisions in one ecosystem will affect the other. We need better understanding of the interactions and interdependencies of these ecosystems, ecosystem ecology is an inherently interdisciplinary field of study. An individual ecosystem is composed of populations of organisms, interacting within communities, and contributing to the cycling of nutrients, the ecosystem is the principal unit of study in ecosystem ecology. Population, community, and physiological ecology provide many of the biological mechanisms influencing ecosystems. Flowing of energy and cycling of matter at the level are often examined in ecosystem ecology, but, as a whole. Ecosystem ecology approaches organisms and abiotic pools of energy and nutrients as a system which distinguishes it from associated sciences such as biogeochemistry. Biogeochemistry and hydrology focus on several fundamental ecosystem processes such as biologically mediated chemical cycling of nutrients, ecosystem ecology forms the mechanistic basis for regional or global processes encompassed by landscape-to-regional hydrology, global biogeochemistry, and earth system science. Ecosystem ecology is philosophically and historically rooted in terrestrial ecology, later work by Eugene Odum and Howard T. Odum quantified flows of energy and matter at the ecosystem level, thus documenting the general ideas proposed by Clements and his contemporary Charles Elton. In this model, energy flows through the system were dependent on biotic and abiotic interactions of each individual component. Later work demonstrated that these interactions and flows applied to nutrient cycles, changed over the course of succession, transfers of energy and nutrients are innate to ecological systems regardless of whether they are aquatic or terrestrial. Thus, ecosystem ecology has emerged from important biological studies of plants, animals, terrestrial, aquatic, ecosystem services are ecologically mediated functional processes essential to sustaining healthy human societies. Nutrient cycling is a fundamental to agricultural and forest production
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Mesocosm
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A mesocosm is any outdoor experimental system that examines the natural environment under controlled conditions. In this way mesocosm studies provide a link between field surveys and highly controlled laboratory experiments, Mesocosms also tend to be medium-sized to large and contain multiple trophic levels of interacting organisms. In contrast to laboratory experiments, mesocosm studies are normally conducted outdoors in order to incorporate natural variation, by manipulating gradients mesocosm studies can extend beyond available data helping to build better models of the effects of different scenarios. Mesocosm experiments also tend to include replication of different treatment levels, manipulating something can give us an idea as to what to expect if something were to occur in that ecosystem or environment. For indoor mesocosms, growth chambers allow us to control the experiment and you can place plants in a growth chamber and manipulate the air, temperature, heat and light distribution and observe the effects when exposed to different amounts of each factor. Greenhouses also contribute to mesocosm studies although sometimes, it may induce climate change, interfering with the experiment, using growth chambers for a laboratory experiment is sometimes a disadvantage due to the limited amount of space. Mazzeo and colleagues examined the eating habits of Hoplias malabaricus fish when exposed to different amounts of phytoplankton, zooplankton, three months prior to conducting the experiment, they maintained an average precipitation, air temperature, and overall subtropical environment. Using 12 units, they filled them with water, sand and plants. After careful preparation, Mazzeo et al. began the experiment dividing those units into categories of a control and 3 experiments, flanagan and McCauley tested the effects of climate warming on carbon dioxide concentration on shallow ponds by creating an eight-cylinder shaped in situ mesocosms. They divided it into four controls and four experiments on University of Calgarys campus pond and those mesocosms contained openings underneath and were submerged at the same depth as the pond. By carefully sustaining the sediments and temperature from any changes, the production of zooplankton, after manipulation, they measured the sediments at the bottom of the pond for carbon dioxide concentration. Example publications of studies using the MERL mesocosms include, Hinga. Lee, J. W. Farrington, K. Tjessem, biogeochemistry of benzanthracene in an enclosed marine ecosystem. Controlled marine ecosystems- A tool for studying stable trace metal cycles, Long-term response, pp. 123–135 In, G. D. Grice and M. R. Reeves, Marine Mesocosms, Biological and Chemical Research in Experimental Ecosystems. Utility of mesocosms to assess marine pollution, Maryland Sea Grant College, College Park, Maryland. The effects of the filter feeding clam Mercenaria mercenaria on carbon cycling in experimental marine mesocosms, a comparison of system oxygen and carbon dioxide and C-14 measurements of metabolism in estuarine mesocosms. Are estuaries traps for anthropogenic nutrients, phosphorus and nitrogen limitation of primary production in a simulated estuarine gradient. The impacts of aquacultured oysters, Crassostrea virginica on water quality and sedimentation, results of a mesocosm study
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Stephen R. Carpenter
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Stephen Russell Carpenter is an American lake ecologist who focuses on lake Eutrophication which is the over-enrichment of lake ecosystems leading to toxic blooms of micro-organisms and fish kills. Stephen Carpenter was born July 5,1952, in Kansas City, Missouri and his father, Richard, a chemist, was the Director of the National Academies’ Board on Environmental Studies and Toxicology, so Carpenter was immersed in science at a young age. In his youth, Carpenter spent his summers on his grandfather’s farm in Missouri, during this time he and his cousins enjoyed fishing and camping in the nearby wilderness. “Hiking, camping, fishing, and hunting all together in ecology. “I was really excited when I discovered there was a way to get paid for being a scientist outdoors. ”During his undergraduate years he met his wife, Susan Moths, whom he married in the same year he finished his doctoral dissertation,1979. He began a career at the University of Notre Dame where he continued to work on lake research at the university’s field station near Land O’ Lakes Wisconsin. Here he created a broadly scoped study of lake ecosystem to include plants and animals. In 1982 he began work on the Trophic Cascades Project, which involved the dynamics of the lake ecosystems, after 10 years spent at Notre Dame, he returned to Madison to a faculty position in the Department of Zoology. Madison had a strong limnology program allowing him to other research including the accumulation of polychlorinated biphenyls in fish. He resumed work on the Madison lakes, including Lake Mendota and his studies on the phosphorus cycle focused on nonpoint phosphorus pollution and how elevated phosphorus concentrations impacted the ecosystem of Lake Mendota. These investigations led Carpenter to devise strategies to manage the phosphorus cycle, Carpenter is Chair of the Science Committee for the Program on Ecosystem Change and Society of the Future Earth. He is co-Editor in Chief of the journal Ecosystems, and a member of governing boards for the Stockholm Resilience Centre, in 2000-2005 he was co-chair of the Scenarios Working Group of the Millennium Ecosystem Assessment. He led the North Temperate Lakes research site of the Long Term Ecological Research Network program at the University of Wisconsin in 1999-2009 and he is a former President of the Ecological Society of America. As of 2011, Carpenter has published 5 books and about 400 scientific papers, book chapters, reviewed reports, carpenters research interest is in whole-ecosystem experiments and adaptive ecosystem management in freshwaters. Nonpoint pollution of surface waters with phosphorus and nitrogen, management of Eutrophication for Lakes Subject to Potentially Irreversible Change. Early Warnings of Regime Shifts, A Whole-Ecosystem Experiment, official Web page at Wisconsin Stockholm Water Prize Profile
30.
White Mountains (New Hampshire)
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The White Mountains are a mountain range covering about a quarter of the state of New Hampshire and a small portion of western Maine in the United States. They are part of the northern Appalachian Mountains and the most rugged mountains in New England, the range is heavily visited due to its proximity to Boston and, to a lesser extent, New York City and Montreal. Most of the area is land, including the White Mountain National Forest. Its most famous mountain is 6, 288-foot Mount Washington, which is the highest peak in the Northeastern U. S. Mount Washington is part of a line of summits, the Presidential Range, that are named after U. S. presidents and other prominent Americans. The White Mountains also include the Franconia Range, Sandwich Range, Carter-Moriah Range and Kinsman Range in New Hampshire, in all, there are 48 peaks within New Hampshire as well as one in Maine over 4,000 feet, known as the Four-thousand footers. The Whites are known for a system of alpine huts for hikers operated by the Appalachian Mountain Club, the Appalachian Trail crosses the area from southwest to northeast. It is not clear where the name White Mountains came from, there is no record of what Native Americans called the range, although pre-Colonial names for many individual peaks are known. The name and similar such as White Hills or Wine Hills are found in literature from Colonial times. According to tradition, the mountains were first sighted from shipboard off the coast near the Piscataqua estuary, the highest peaks would often be snow-capped, appearing white. An alternate theory is that the granite of the summits looked white to observers. The White Mountains are a section of the larger New England province. The magma intrusions forming the White Mountains today were created 124 to 100 million years ago as the North American Plate moved westward over the New England hotspot, widespread evidence of glaciation may be seen in the U-shaped form of various notches, or mountain passes. Glacial cirques form the heads of Tuckerman Ravine on Mt. Washington, glacial striations are visible at numerous locations, including on the exposed rocks at the summit of Pine Mountain in Gorham. The Mount Washington Auto Road and the historic Mount Washington Cog Railway ascend the ranges highest peak, heavily visited Arethusa Falls, the second tallest waterfall in New Hampshire, lies on a southwest flank of Crawford Notch. The Old Man of the Mountain, a formation on Cannon Mountain that resembled the craggy profile of a mans face, was a White Mountain landmark until it fell in May 2003. It remains the symbol of New Hampshire. The range also includes a feature dubbed The Basin, consisting of a granite bowl,20 feet in diameter, fed by a waterfall. The areas around The Basin are popular spots for swimming in the ice-cold mountain-fed water, some of the earliest maps of the White Mountains were produced as tourist maps and not topographical maps
31.
Chemistry
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Chemistry is a branch of physical science that studies the composition, structure, properties and change of matter. Chemistry is sometimes called the science because it bridges other natural sciences, including physics. For the differences between chemistry and physics see comparison of chemistry and physics, the history of chemistry can be traced to alchemy, which had been practiced for several millennia in various parts of the world. The word chemistry comes from alchemy, which referred to a set of practices that encompassed elements of chemistry, metallurgy, philosophy, astrology, astronomy, mysticism. An alchemist was called a chemist in popular speech, and later the suffix -ry was added to this to describe the art of the chemist as chemistry, the modern word alchemy in turn is derived from the Arabic word al-kīmīā. In origin, the term is borrowed from the Greek χημία or χημεία and this may have Egyptian origins since al-kīmīā is derived from the Greek χημία, which is in turn derived from the word Chemi or Kimi, which is the ancient name of Egypt in Egyptian. Alternately, al-kīmīā may derive from χημεία, meaning cast together, in retrospect, the definition of chemistry has changed over time, as new discoveries and theories add to the functionality of the science. The term chymistry, in the view of noted scientist Robert Boyle in 1661, in 1837, Jean-Baptiste Dumas considered the word chemistry to refer to the science concerned with the laws and effects of molecular forces. More recently, in 1998, Professor Raymond Chang broadened the definition of chemistry to mean the study of matter, early civilizations, such as the Egyptians Babylonians, Indians amassed practical knowledge concerning the arts of metallurgy, pottery and dyes, but didnt develop a systematic theory. Greek atomism dates back to 440 BC, arising in works by such as Democritus and Epicurus. In 50 BC, the Roman philosopher Lucretius expanded upon the theory in his book De rerum natura, unlike modern concepts of science, Greek atomism was purely philosophical in nature, with little concern for empirical observations and no concern for chemical experiments. Work, particularly the development of distillation, continued in the early Byzantine period with the most famous practitioner being the 4th century Greek-Egyptian Zosimos of Panopolis. He formulated Boyles law, rejected the four elements and proposed a mechanistic alternative of atoms. Before his work, though, many important discoveries had been made, the Scottish chemist Joseph Black and the Dutchman J. B. English scientist John Dalton proposed the theory of atoms, that all substances are composed of indivisible atoms of matter. Davy discovered nine new elements including the alkali metals by extracting them from their oxides with electric current, british William Prout first proposed ordering all the elements by their atomic weight as all atoms had a weight that was an exact multiple of the atomic weight of hydrogen. The inert gases, later called the noble gases were discovered by William Ramsay in collaboration with Lord Rayleigh at the end of the century, thereby filling in the basic structure of the table. Organic chemistry was developed by Justus von Liebig and others, following Friedrich Wöhlers synthesis of urea which proved that organisms were, in theory
32.
Acid rain
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Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions. It can have effects on plants, aquatic animals and infrastructure. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide, some governments have made efforts since the 1970s to reduce the release of sulfur dioxide and nitrogen oxide into the atmosphere with positive results. Nitrogen oxides can also be produced naturally by lightning strikes, Acid rain is a popular term referring to the deposition of a mixture from wet and dry acidic components. Distilled water, once carbon dioxide is removed, has a neutral pH of 7, liquids with a pH less than 7 are acidic, and those with a pH greater than 7 are alkaline. Clean or unpolluted rain has an acidic pH, but usually no lower than 5, a common example is nitric acid produced by electric discharge in the atmosphere such as lightning. Acid deposition as an issue would include additional acids other than H2CO3. The corrosive effect of polluted, acidic city air on limestone and marble was noted in the 17th century by John Evelyn, since the Industrial Revolution, emissions of sulfur dioxide and nitrogen oxides into the atmosphere have increased. In 1852, Robert Angus Smith was the first to show the relationship between rain and atmospheric pollution in Manchester, England. Though acidic rain was discovered in 1853, it was not until the late 1960s that scientists began widely observing and studying the phenomenon, the term acid rain was coined in 1872 by Robert Angus Smith. Canadian Harold Harvey was among the first to research a dead lake, occasional pH readings in rain and fog water of well below 2.4 have been reported in industrialized areas. Industrial acid rain is a problem in China and Russia. These areas all burn sulfur-containing coal to heat and electricity. The problem of acid rain has not only increased with population and industrial growth, the use of tall smokestacks to reduce local pollution has contributed to the spread of acid rain by releasing gases into regional atmospheric circulation. Often deposition occurs a considerable distance downwind of the emissions, with mountainous regions tending to receive the greatest deposition, an example of this effect is the low pH of rain which falls in Scandinavia. The earliest report about acid rain in the United States was from the evidence from Hubbard Brook Valley. In 1972, a group of scientists including Gene Likens discovered the rain that was deposited at White Mountains of New Hampshire was acidic, the pH of the sample was measured to be 4.03 at Hubbard Brook. The Hubbard Brook Ecosystem Study followed up with a series of research that analyzed the effects of acid rain
33.
Ion
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An ion is an atom or a molecule in which the total number of electrons is not equal to the total number of protons, giving the atom or molecule a net positive or negative electrical charge. Ions can be created, by chemical or physical means. In chemical terms, if an atom loses one or more electrons. If an atom gains electrons, it has a net charge and is known as an anion. Ions consisting of only a single atom are atomic or monatomic ions, because of their electric charges, cations and anions attract each other and readily form ionic compounds, such as salts. In the case of ionization of a medium, such as a gas, which are known as ion pairs are created by ion impact, and each pair consists of a free electron. The word ion comes from the Greek word ἰόν, ion, going and this term was introduced by English physicist and chemist Michael Faraday in 1834 for the then-unknown species that goes from one electrode to the other through an aqueous medium. Faraday also introduced the words anion for a charged ion. In Faradays nomenclature, cations were named because they were attracted to the cathode in a galvanic device, arrhenius explanation was that in forming a solution, the salt dissociates into Faradays ions. Arrhenius proposed that ions formed even in the absence of an electric current, ions in their gas-like state are highly reactive, and do not occur in large amounts on Earth, except in flames, lightning, electrical sparks, and other plasmas. These gas-like ions rapidly interact with ions of charge to give neutral molecules or ionic salts. These stabilized species are commonly found in the environment at low temperatures. A common example is the present in seawater, which are derived from the dissolved salts. Electrons, due to their mass and thus larger space-filling properties as matter waves, determine the size of atoms. Thus, anions are larger than the parent molecule or atom, as the excess electron repel each other, as such, in general, cations are smaller than the corresponding parent atom or molecule due to the smaller size of its electron cloud. One particular cation contains no electrons, and thus consists of a single proton - very much smaller than the parent hydrogen atom. Since the electric charge on a proton is equal in magnitude to the charge on an electron, an anion, from the Greek word ἄνω, meaning up, is an ion with more electrons than protons, giving it a net negative charge. A cation, from the Greek word κατά, meaning down, is an ion with fewer electrons than protons, there are additional names used for ions with multiple charges
34.
Aquatic ecosystem
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An aquatic ecosystem is an ecosystem in a body of water. Communities of organisms that are dependent on other and on their environment live in aquatic ecosystems. The two main types of ecosystems are marine ecosystems and freshwater ecosystems. Marine ecosystems cover approximately 71% of the Earths surface and contain approximately 97% of the planets water and they generate 32% of the worlds net primary production. They are distinguished from freshwater ecosystems by the presence of dissolved compounds, especially salts, approximately 85% of the dissolved materials in seawater are sodium and chlorine. Seawater has a salinity of 35 parts per thousand of water. Actual salinity varies among different marine ecosystems, marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, the benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides, in this figure it is termed the littoral zone, other near-shore zones can include estuaries, salt marshes, coral reefs, lagoons and mangrove swamps. In the deep water, hydrothermal vents may occur where chemosynthetic sulfur bacteria form the base of the food web, classes of organisms found in marine ecosystems include brown algae, dinoflagellates, corals, cephalopods, echinoderms, and sharks. Fishes caught in marine ecosystems are the biggest source of commercial foods obtained from wild populations, environmental problems concerning marine ecosystems include unsustainable exploitation of marine resources, marine pollution, climate change, and building on coastal areas. Freshwater ecosystems cover 0. 78% of the Earths surface and inhabit 0. 009% of its total water and they generate nearly 3% of its net primary production. Freshwater ecosystems contain 41% of the known fish species. There are three types of freshwater ecosystems, Lentic, slow moving water, including pools, ponds. Lotic, faster moving water, for example streams and rivers, wetlands, areas where the soil is saturated or inundated for at least part of the time. Lake ecosystems can be divided into zones, one common system divides lakes into three zones. The first, the zone, is the shallow zone near the shore. This is where rooted wetland plants occur, the offshore is divided into two further zones, an open water zone and a deep water zone
35.
Freshwater ecosystem
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Freshwater ecosystems are a subset of Earths aquatic ecosystems. They include lakes and ponds, rivers, streams, springs and they can be contrasted with marine ecosystems, which have a larger salt content. Freshwater habitats can be classified by different factors, including temperature, light penetration, Freshwater ecosystems can be divided into lentic ecosystems and lotic ecosystems. Limnology is a study about freshwater ecosystems and it is a part of hydrobiology. Original attempts to understand and monitor freshwater ecosystems were spurred on by threats to human health, early monitoring focussed on chemical indicators, then bacteria, and finally algae, fungi and protozoa. A new type of monitoring involves differing groups of organisms and the conditions associated with them. Current biomonitoring techniques focus mainly on community structure or biochemical oxygen demand, responses are measured by behavioural changes, altered rates of growth, reproduction or mortality. Macroinvertebrates are most often used in these models because of well known taxonomy, ease of collection, sensitivity to a range of stressors, most of these measurements are difficult to extrapolate on a large scale, however. The use of sites is common when assessing what a healthy freshwater ecosystem should “look like”. Reference sites are easier to reconstruct in standing water than moving water, common chemical stresses on freshwater ecosystem health include acidification, eutrophication and copper and pesticide contamination. Over 123 freshwater fauna species have gone extinct in North America since 1900. Of North American freshwater species, an estimated 48. 5% of mussels,22. 8% of gastropods,32. 7% of crayfishes,25. 9% of amphibians, and 21. 3% of fishes are either endangered or threatened. Extinction rates of species may increase severely into the next century because of invasive species, loss of keystone species. Projected extinction rates for freshwater animals are around five times greater than for land animals, recent extinction trends can be attributed largely to sedimentation, stream fragmentation, chemical and organic pollutants, dams, and invasive species. Ecology Freshwater Leathwick J. R. Collier K. Chadderton L. Identifying freshwater ecosystems with nationally important natural heritage values, friberg, N, Bonada, N. Bradley, D. C. Grey, J. Hayes, R. B. Hildrew, A. G. Lamouroux, N. Trimmer, M. Woodward G. Biomonitoring of Human Impacts in Freshwater Ecosystems, The Good, the Bad, ricciardi, A. & Rasmussen, J. B. Extinction Rates of North American Freshwater Fauna, tao, S. Dawson, R. W. Pen-gang, L. & Jun, C. Lake Ecosystem Health Assessment, Indicators and Methods
36.
Rainforest
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The monsoon trough, alternatively known as the intertropical convergence zone, plays a significant role in creating the climatic conditions necessary for the Earths tropical rainforests. Around 40% to 75% of all species are indigenous to the rainforests. It has been estimated there may be many millions of species of plants, insects. Tropical rainforests have been called the jewels of the Earth and the worlds largest pharmacy, the undergrowth in some areas of a rainforest can be restricted by poor penetration of sunlight to ground level. If the leaf canopy is destroyed or thinned, the ground beneath is soon colonized by a dense, tangled growth of vines, shrubs and small trees, the term jungle is also sometimes applied to tropical rainforests generally. Tropical rainforests are characterized by a warm and wet climate with no dry season. Mean monthly temperatures exceed 18 °C during all months of the year, average annual rainfall is no less than 168 cm and can exceed 1,000 cm although it typically lies between 175 cm and 200 cm. Many of the tropical forests are associated with the location of the monsoon trough. The broader category of tropical moist forests are located in the zone between the Tropic of Cancer and Tropic of Capricorn. Tropical forests have been called the Earths lungs, although it is now known that rainforests contribute little net oxygen addition to the atmosphere through photosynthesis, Tropical forests cover a large part of the globe, but temperate rainforests only occur in few regions around the world. Temperate rainforests are rainforests in temperate regions and they occur in North America, in Europe, in East Asia, in South America and also in Australia and New Zealand. A tropical rainforest typically has a number of layers, each with different plants, examples include the emergent, canopy, understorey and forest floor layers. They need to be able to withstand the hot temperatures and strong winds that occur above the canopy in some areas, eagles, butterflies, bats and certain monkeys inhabit this layer. The canopy layer contains the majority of the largest trees, typically 30 metres to 45 metres tall, the densest areas of biodiversity are found in the forest canopy, a more or less continuous cover of foliage formed by adjacent treetops. The canopy, by some estimates, is home to 50 percent of all plant species, epiphytic plants attach to trunks and branches, and obtain water and minerals from rain and debris that collects on the supporting plants. The fauna is similar to found in the emergent layer. A quarter of all species are believed to exist in the rainforest canopy. Scientists have long suspected the richness of the canopy as a habitat, true exploration of this habitat only began in the 1980s, when scientists developed methods to reach the canopy, such as firing ropes into the trees using crossbows
37.
Biodiversity
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Biodiversity, a contraction of biological diversity, generally refers to the variety and variability of life on Earth. One of the most widely used definitions defines it in terms of the variability within species and it is a measure of the variety of organisms present in different ecosystems. This can refer to genetic variation, ecosystem variation, or species variation within an area, biome, terrestrial biodiversity tends to be greater near the equator, which seems to be the result of the warm climate and high primary productivity. Biodiversity is not distributed evenly on Earth, and is richest in the tropics and these tropical forest ecosystems cover less than 10 per cent of earths surface, and contain about 90 percent of the worlds species. Marine biodiversity tends to be highest along coasts in the Western Pacific, there are latitudinal gradients in species diversity. Biodiversity generally tends to cluster in hotspots, and has been increasing through time, the number and variety of plants, animals and other organisms that exist is known as biodiversity. It is a component of nature and it ensures the survival of human species by providing food, fuel, shelter, medicines. The richness of biodiversity depends on the conditions and area of the region. All species of plants taken together are known as flora and about 300,000 species of plants are known to date, all species of animals taken together are known as fauna which includes birds, mammals, fish, reptiles, insects, crustaceans, molluscs, etc. Rapid environmental changes typically cause mass extinctions, more than 99 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Estimates on the number of Earths current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. More recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described, the total amount of related DNA base pairs on Earth is estimated at 5.0 x 1037 and weighs 50 billion tonnes. In comparison, the mass of the biosphere has been estimated to be as much as 4 TtC. In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor of all living on Earth. The age of the Earth is about 4.54 billion years old, there are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. Other early physical evidence of a substance is graphite in 3.7 billion-year-old meta-sedimentary rocks discovered in Western Greenland. More recently, in 2015, remains of life were found in 4.1 billion-year-old rocks in Western Australia. According to one of the researchers, If life arose relatively quickly on Earth, then it could be common in the universe
38.
Senegal
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Senegal, officially the Republic of Senegal, is a country in West Africa. Senegal is bordered by Mauritania in the north, Mali to the east, Guinea to the southeast, and Guinea-Bissau to the southwest. Senegal also borders The Gambia, a country occupying a narrow sliver of land along the banks of the Gambia River, Senegal also shares a maritime border with Cape Verde. Senegals economic and political capital is Dakar and it is the westernmost country in the mainland of the Old World, or Afro-Eurasia, and owes its name to the Senegal River, which borders it to the east and north. The name Senegal comes from the Wolof Sunuu Gaal, which means Our Boat, Senegal covers a land area of almost 197,000 square kilometres and has an estimated population of about 15 million. The climate is Sahelian, but there is a rainy season, the territory of modern Senegal has been inhabited by various ethnic groups since prehistory. Organized kingdoms emerged around the century, and parts of the country were ruled by prominent regional empires such as the Jolof Empire. The present state of Senegal has its roots in European colonialism, which began during the mid-15th century, the establishment of coastal trading posts gradually led to control of the mainland, culminating in French rule of the area by the 19th century, albeit amid much local resistance. Senegal peacefully attained independence from France in 1960, and has since been among the politically stable countries in Africa. Senegals economy is centered mostly on commodities and natural resources, major industries are fish processing, phosphate mining, fertilizer production, petroleum refining, construction materials, and ship construction and repair. As in most African nations, agriculture is a sector, with Senegal producing several important cash crops, including peanuts, sugarcane, cotton, green beans, tomatoes, melons. Owing to its stability, tourism and hospitality are also burgeoning sectors. A multiethnic and secular nation, Senegal is predominantly Sunni Muslim with Sufi, French is the official language, although many native languages are spoken and recognized. Since April 2012 Senegals president has been Macky Sall, Senegal has been a member of the Organisation internationale de la Francophonie since 1970. Senegal is named after the Senegal River, the etymology of which is contested, one popular theory is that it stems from the Wolof phrase sunu gaal, which means our canoe, resulting from a miscommunication between 15th-century Portuguese sailors and Wolof fishermen. The our canoe theory has been embraced in modern Senegal for its charm. It is frequently used in appeals to national solidarity, frequently heard in the media, modern historians believe the name probably refers to the Sanhaja, Berbers who lived on the northern side of the river. A competing theory is that it derives from the town of Sanghana
![Coral reefs are a highly productive marine ecosystem.[2]](/wiki/File:Blue_Linckia_Starfish.JPG)
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