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<p><strong>Ecology</strong> (from Greek: οίκος, <em>oikos</em>, "household"; and λόγος, <em>logos</em>, "knowledge") is the scientific study of the distribution and abundance of living organisms and how the distribution and abundance are affected by interactions between the organisms and their Ecosystem includes both physical properties, which can be described as the sum of local abiotic factors such as insolation (sunlight), climate, and geology, and biotic factors, which are other organisms that share its habitat. The term <em>oekologie</em> was coined in 1866 by the German biologist Ernst Haeckel.</p>
<p>The word "ecology" is often used in common parlance as a synonym for the natural environment or environmentalism. Likewise "ecologic" or "ecological" is often taken in the sense of environmentally friendly. </p><p> [[dd]]</p>
<h2><span class="mw-headline">Scope</span></h2>
<p>Ecology is usually considered a branch of biology, the general science that studies living organisms. Organisms can be studied at many different levels, from proteins and nucleic acids (in biochemistry and molecular biology), to cells (in cellular biology), to individuals (in botany, zoology, and other similar disciplines), and finally at the level of populations, communities, and ecosystems, to the biosphere as a whole; these latter strata are the primary subjects of ecological inquiry. Ecology is a multi-disciplinary science. Because of its focus on the higher levels of the organization of life on earth and on the interrelations between organisms and their environment, ecology draws heavily on many other branches of science, especially geology and geography, meteorology, pedology, genetics, chemistry, and physics. Thus, ecology is considered by some to be a holistic science, one that over-arches older disciplines such as biology which in this view become sub-disciplines contributing to ecological knowledge.</p>
<p>Consider the ways an ecologist might approach studying the life of honeybees:</p>
<ul>
<li>The behavioral relationship between individuals of a species is behavioral ecology — for example, the study of the queen bee, and how she relates to the worker bees and the drones. </li>
</ul>
<ul>
<li>The organized activity of a species is community ecology; for example, the activity of bees assures the pollination of flowering plants. Bee hives additionally produce honey which is consumed by still other species, such as bears. </li> <li>The relationship between the environment and a species is environmental ecology — for example, the consequences of environmental change on bee activity. Bees may die out due to environmental changes (see pollinator decline). The environment simultaneously affects and is a consequence of this activity and is thus intertwined with the survival of the species. </li>
</ul>
<p> </p>
<p>Ecology is a broad discipline comprising many sub-disciplines. A common, broad classification, moving from lowest to highest complexity, where complexity is defined as the number of entities and processes in the system under study, is:</p>
<ul>
<li>Ecophysiology and Behavioral ecology examine adaptations of the individual to its environment. </li> <li>Autecology studies the dynamics of populations of a single species. </li> <li>Community ecology (or <strong>synecology</strong>) focuses on the interactions between species within an ecological community. </li> <li>Ecosystem ecology studies the flows of energy and matter through the biotic and abiotic components of ecosystems. </li> <li>Landscape ecology examines processes and relationship across multiple ecosystems or very large geographic areas. </li>
</ul>
<p>Ecology can also be sub-divided according to the species of interest into fields such as animal ecology, plant ecology, insect ecology, and so on. Another frequent method of subdivision is by biome studied, e.g., Arctic ecology (or polar ecology), tropical ecology, desert ecology, etc. The primary technique used for investigation is often used to subdivide the discipline into groups such as chemical ecology, genetic ecology, field ecology, statistical ecology, theoretical ecology, and so forth. These fields are not mutually exclusive; one could be a theoretical plant community ecologist, or a polar ecologist interested in animal genetics. Animals can be reproduced by plants.</p>
<p>The main questions when studying an ecosystem are:</p>
<ul>
<li>Whether the colonization of a barren area could be carried out </li> <li>Investigation the ecosystem's dynamics and changes </li> <li>The methods of which an ecosystem interacts at local, regional and global scale </li> <li>Whether the current state is stable </li> <li>Investigating the value of an ecosystem and the ways and means that interaction of ecological systems provides benefits to humans, especially in the provision of healthy water. </li>
</ul>
<p>Ecosystems are often classified by reference to the biotopes concerned. The following ecosystems may be defined:</p>
<ul>
<li>As continental ecosystems, such as forest ecosystems, meadow ecosystems such as steppes or savannas, or agro-ecosystems </li> <li>As ecosystems of inland waters, such as lentic ecosystems such as lakes or ponds; or lotic ecosystems such as rivers </li> <li>As oceanic ecosystems. </li>
</ul>
<p>Another classification can be done by reference to its communities, such as in the case of an human ecosystem.</p>
<p><strong>Abiotic factors</strong> are geological, geographical, hydrological and climatological parameters. A <strong>biotope</strong> is an environmentally uniform region characterized by a particular set of abiotic ecological factors. Specific abiotic factors include:</p>
<ul>
<li>Water, which is at the same time an essential element to life and a milieu </li> <li>Air, which provides oxygen, nitrogen, and carbon dioxide to living species and allows the dissemination of pollen and spores </li>
<li>Soil, at the same time source of nutriment and physical support
<ul>
<li>Soil pH, salinity, nitrogen and phosphorus content, ability to retain water, and density are all influential </li>
</ul>
</li>
<li>Temperature, which should not exceed certain extremes, even if tolerance to heat is significant for some species </li> <li>Light, which provides energy to the ecosystem through photosynthesis </li> <li>Natural disasters can also be considered abiotic </li>
</ul>
<p><strong>Biocenose</strong>, or community, is a group of populations of plants, animals, micro-organisms. Each population is the result of procreations between individuals of same species and cohabitation in a given place and for a given time. When a population consists of an insufficient number of individuals, that population is threatened with extinction; the extinction of a species can approach when all biocenoses composed of individuals of the species are in decline. In small populations, consanguinity (inbreeding) can result in reduced genetic diversity that can further weaken the biocenose.</p>
<dl><dd><strong>Intraspecific relations</strong> are those which are established between individuals of the same species, forming a population. They are relations of co-operation or competition, with division of the territory, and sometimes organization in hierarchical societies. </dd></dl>
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<div classstyle="thumbinnerwidth: 302px" styleclass="WIDTH: 302pxthumbinner"><img class="thumbimage" height="225" alt="An ant lion lies in wait under its pit trap, built in dry dust under a building, awaiting unwary insects that fall in. Many pest insects are partly or wholly controlled by other insect predators." width="300" longdesc="/wiki/Image:Ant_lion_8785.JPG" height="225" src="http://upload.wikimedia.org/wikipedia/en/thumb/d/d5/Ant_lion_8785.JPG/300px-Ant_lion_8785.JPG" />
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<div classstyle="magnifyfloat: right" styleclass="FLOAT: rightmagnify"><img heightalt="11" altwidth="15" widthheight="1511" src="http://en.wikipedia.org/skins-1.5/common/images/magnify-clip.png" /></div>
An ant lion lies in wait under its pit trap, built in dry dust under a building, awaiting unwary insects that fall in. Many pest insects are partly or wholly controlled by other insect predators.</div>
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<p>In an ecosystem, the connections between species are generally related to food and their role in the food chain. There are three categories of organisms:</p>
<ul>
<li><em>Producers</em> -- usually plants which are capable of photosynthesis but could be other organisms such as bacteria around ocean vents that are capable of chemosynthesis. </li> <li><em>Consumers</em> -- animals, which can be primary consumers (herbivorous), or secondary or tertiary consumers (carnivorous and omnivores). </li> <li><em>Decomposers</em> -- bacteria, mushrooms which degrade organic matter of all categories, and restore minerals to the environment. </li>
</ul>
<p>These relations form sequences, in which each individual consumes the preceding one and is consumed by the one following, in what are called food chains or food network. In a food network, there will be fewer organisms at each level as one follows the links of the network up the chain.</p>
<p>The productivity of ecosystems is sometimes estimated by comparing three types of land-based ecosystems and the total of aquatic ecosystems:</p>
<ul>
<li>The forests (1/3 of the Earth's land area) contain dense biomasses and are very productive. The total production of the world's forests corresponds to half of the primary production. </li> <li>Savannas, meadows, and marshes (1/3 of the Earth's land area) contain less dense biomasses, but are productive. These ecosystems represent the major part of what humans depend on for food. </li> <li>Extreme ecosystems in the areas with more extreme climates -- deserts and semi-deserts, tundra, alpine meadows, and steppes -- (1/3 of the Earth's land area) have very sparse biomasses and low productivity </li> <li>Finally, the marine and fresh water ecosystems (3/4 of Earth's surface) contain very sparse biomasses (apart from the coastal zones). </li>
</ul>
<p>Humanity's actions over the last few centuries have seriously reduced the amount of the Earth covered by forests (deforestation), and have increased agro-ecosystems (agriculture). In recent decades, an increase in the areas occupied by extreme ecosystems has occurred (desertification).</p>
<p>Some usually quoted examples as ecological crises are:</p>
<ul>
<li>The Exxon Valdez Oil Spill off the coast of Alaska in 1989 </li> <li>Permian-Triassic extinction event 250 million of years ago </li> <li>Cretaceous-Tertiary extinction event 65 million years ago </li> <li>Global warming related to the Greenhouse effect. Warming could involve flooding of the Asian deltas (see also eco refugees), multiplication of extreme weather phenomena and changes in the nature and quantity of the food resources (see Global warming and agriculture). See also international Kyoto Protocol. </li> <li>Ozone layer hole issue </li> <li>Deforestation and desertification, with disappearance of many species. </li> <li>The nuclear meltdown at Chernobyl in 1986 caused the death of many people and animals from cancer, and caused mutations in a large number of animals and people. The area around the plant is now abandoned by humans because of the large amount of radiation generated by the meltdown. Twenty years after the accident, the animals have returned. </li>
</ul>
<p> </p>
<h2><span class="mw-headline">See also</span></h2>
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<div class="floatleft"><span></span> </div><div style="MARGINmargin-LEFTleft: 60px">Wikimedia Commons has media related to:<div style="MARGINmargin-LEFTleft: 10px"><em><strong>Ecology</strong></em></div>
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<div style="FLOATfloat: left"><div class="floatnone"><span></span> </div>
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<div style="MARGINmargin-LEFTleft: 60px">At Wikiversity you can learn more and teach others about <strong>Ecology</strong> at:<div style="MARGINmargin-LEFTleft: 10px">The Department of Ecology</div>
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<div style="FLOATfloat: left"><div class="floatnone"><span></span> </div>
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<div style="MARGINmargin-LEFTleft: 60px">Wikibooks has more on the topic of<div style="MARGINmargin-LEFTleft: 10px"><em>Ecology</em></div>
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<div style="float: right" class="infobox sisterproject" style="FLOAT: right"><div style="FLOATfloat: left"><div class="floatnone"><span></span> </div>
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<div style="MARGINmargin-LEFTleft: 60px">Look up <em><strong>Ecology</strong></em> in<br />
Wiktionary, the free dictionary.</div>
</div>
<h3><span class="mw-headline">Lists</span></h3>
<ul>
<li>List of basic biology topics </li> <li>List of biology topics </li> <li>List of basic ecology topics </li> <li>List of ecology topics </li> <li>List of ecologists </li> <li>Important publications in ecology </li>
</ul>
<p> </p>
<h3><span class="mw-headline">Related topics</span></h3>
<ul>
<li>Deep Ecology </li> <li>Ecological economics </li> <li>Ecology movement </li> <li>Ecosystem </li> <li>Ecosystem model </li> <li>ELDIS, a database on ecological aspects of economical development. </li> <li>Environmental art </li> <li>Environmental science </li> <li>Environmental technology </li> <li>Environmental communication </li> <li>Environmental Psychology </li> <li>Forest farming </li> <li>Human ecology </li> <li>Knowledge ecology </li> <li>Social ecology </li>
</ul>
<p><a id="External_links" name="External_links"></a></p>
<ul>
<li>[http://ecome.org Ecome]: The ome of Ecosystem.</li>
<li><a class="external text" title="http://www.barrameda.com.ar/ecology" rel="nofollow" href="http://www.barrameda.com.ar/ecology"><font color="#0066cc">What is Ecology?</font></a> </li> <li><a class="external text" title="http://www.econguru.com/fundamentals_of_ecology/" rel="nofollow" href="http://www.econguru.com/fundamentals_of_ecology/"><font color="#0066cc">Fundamentals of Ecology</font></a> Textbook-style investigation to the economy of nature, breaks down in 4 chapters from Population to Ecosystem. </li>
</ul>
<ul>
<li> </li> <li>생명체와 환경 간 상호 작용에 대한 연구. </li>
</ul>
