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Niche construction is the process in which an organism alters its own (or other species') environment, often but not always in a manner that increases its chances of survival. Changes that organisms bring about in their worlds that are of no evolutionary or ecological consequence are not examples of niche construction.〔 〕 Several biologists have argued that niche construction is as important to evolution as natural selection (i.e., not only does an environment cause changes in species through selection, but species also cause changes in their environment through niche construction). This back-and-forth creates a feedback relationship between natural selection and niche-construction: when organisms affect their environment, that change can then cause a shift in what traits are being naturally selected for. The effect of niche construction is especially pronounced in situations where environmental alterations persist for several generations, introducing the evolutionary role of ecological inheritance. Less drastic niche-constructing behaviors are also quite possible for an organism. This theory, in conjunction with natural selection, shows that organisms inherit two legacies from their ancestors: genes and a modified environment. Together, these two evolutionary mechanisms determine a population's fitness and what adaptations those organisms develop in the continuation for their survival. ==Examples== *Earthworms: Through a process of modification, earthworms chemically alter the soil in which they live. This change in soil chemistry stimulates an increased fitness in earthworm populations. The subsequent chemical composition of soil produced by earthworm activity also benefits the growth of proximal species of plants and other biota present in the soil.〔Odling-Smee, John F. (2009). "Niche Construction in Evolution, Ecosystems and Developmental Biology". Mapping the Future of Biology, 69-91. ISBN 978-1-4020-9635-8.〕 *Lemon Ants (''Myrmelachista schumanni''): This species of ants employs a specialized method of suppression that regulates the growth of certain trees. Lemon ants make their homes in the bodies of ''Duroia hirsuta'', a species of tree found in the Amazonian rainforest of Peru. To ensure the prevalence of ''Duroia'' trees, Lemon ants employ self-derived quantities of formic acid (a chemical fairly common among species of ants) as a tenacious herbicide. The end result alters the composition of their forest habitat drastically by wiping out arboreal species ill-suited for colony habitation. When observed by humans, the subsequent altered ecologies perpetuated by these ants have been termed the Devil's Gardens.〔Reece, Urry, Cain, Wasserman, Minorsky & Jackson (2011). ''Campbell Biology''. ISBN 978-0-321-55823-7.〕 *Beavers: In the construction of their dams, beavers drastically shape and alter the ecosystem in which they live. Deforestation, effects on soil structure, root structure, turbidity of water, allocation of water and the supply of water downstream are just a handful of exemplars defining beaver niche construction. Beavers express a clear example of the diverse effects perpetuated by the construction of a niche. In the mammalian kingdom beavers are one of the greatest proximal modifiers. *Diatoms in the Bay of Fundy, Canada, provide another example of an ecosystem engineer. Benthic diatoms living in estuarine sediments secrete carbohydrate exudates that bind the sand and stabilize the environment. The diatoms cause a physical state change in the properties of the sand that allows other organisms to colonize the area. The concept of ecosystem engineering brings new conceptual implications for the discipline of conservation biology. *Pine Trees & Chaparrals: Chaparrals and pines have been found to express niche constructing behavior in response to the effects of forest fire. These trees and shrubs increase the frequency of fire by affecting the composition of the forest floor. They achieve this end through the dispersal of needles, cones, seeds and oils, essentially littering the forest floor. The benefit of this activity is compounded by an adaptation in these particular flora that has selected for a resistance to fire. The evolutionary exchange (made between both niche construction and natural selection) allows the fire-resistant pine and chaparral to exploit the chemical change that occurs in soil after organic matter has been burned.Humans: See subsection below. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「niche construction」の詳細全文を読む スポンサード リンク
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