“extinction”的概念、定义、翻译、参考文献-科学参考

extinction

Statistics

See branching process.

Biology

1. The irreversible condition of a species or other group of organisms of having no living representatives in the wild, which follows the death of the last surviving individual of that species or group. Extinction may occur on a local or global level; it can result from various human activities, including the destruction of habitats or the overexploitation of species that are hunted or harvested as a resource. Species at the top of a food chain (e.g. large birds of prey) will be more prone to extinction since they exist in relatively small numbers and will be affected by a deleterious change at any of the levels in the food chain. See mass extinction.
2. The termination of a behaviour pattern that is no longer appropriate. For example, dogs can be conditioned to salivate when they hear a bell ring in the absence of a food stimulus (see conditioning). However, if the bell continues to be rung in the absence of food the dogs will gradually stop salivating on hearing the bell.

Geology and Earth Sciences

1. In optical mineralogy, a mineral is said to be in extinction when the vibration direction of the two rays of a doubly refracting crystal coincide with the vibration directions of the two pieces of Polaroid in a thin-section microscope that is parallel to the polarizer and analyser so that no light reaches the eye. This phenomenon occurs four times in a complete 360° rotation of the stage. See oblique extinction; straight extinction; symmetrical extinction; undulose extinction.
2. The elimination of a taxon. This may take place in several ways. In the simplest case the taxon disappears from the record and is not replaced. Alternatively, one taxon may replace another, the earlier group consequently disappearing. Thus there is a process of either subtraction or substitution. Extinction generally takes place at particular times and places but there are recurring periods when episodes of mass extinction have taken place. Environmental catastrophe, occurring for whatever reason, removes many groups from the environment and ecosystems collapse. Eventually new forms appear and evolution resumes. It would appear that periods of mass extinction control the pattern of evolution.

Geography

The end of the existence of a species or group of taxa, or the end of their ability to reproduce. Gaston (2008) PPG 32, 1 observes that rare species are disproportionately vulnerable to extinction in the short term. Loss of a species to chance extinction leaves an area of resource space unoccupied; extinctions could trigger behavioural or evolutionary adaptations (Phillips (2008) PPG 32, 1). Van Kleunen and Richardson (2007) PPG 31, 4 consider the links between species traits and extinction risk and invasiveness. See Kiesling and Aberhan (2007) J. Biogeog. 34, 9 on geographical distribution and extinction risk. Losos and Schluter (2000) Nature 408 explain the relationship as the outcome of the effect of area on immigration and extinction rates. ‘If the twentieth-century question was how to stop extinction, then perhaps the twenty-first-century challenge is how to avoid the total collapse of the biosphere, our life support system’ (W. Adams 2004). See Sanderson et al. (2002) Bioscience 52, 10 on human activity and extinction rates.
See also biodiversity crisis.

单词	extinction
释义	extinction Statistics See branching process. Biology 1. The irreversible condition of a species or other group of organisms of having no living representatives in the wild, which follows the death of the last surviving individual of that species or group. Extinction may occur on a local or global level; it can result from various human activities, including the destruction of habitats or the overexploitation of species that are hunted or harvested as a resource. Species at the top of a food chain (e.g. large birds of prey) will be more prone to extinction since they exist in relatively small numbers and will be affected by a deleterious change at any of the levels in the food chain. See mass extinction. 2. The termination of a behaviour pattern that is no longer appropriate. For example, dogs can be conditioned to salivate when they hear a bell ring in the absence of a food stimulus (see conditioning). However, if the bell continues to be rung in the absence of food the dogs will gradually stop salivating on hearing the bell. Geology and Earth Sciences 1. In optical mineralogy, a mineral is said to be in extinction when the vibration direction of the two rays of a doubly refracting crystal coincide with the vibration directions of the two pieces of Polaroid in a thin-section microscope that is parallel to the polarizer and analyser so that no light reaches the eye. This phenomenon occurs four times in a complete 360° rotation of the stage. See oblique extinction; straight extinction; symmetrical extinction; undulose extinction. 2. The elimination of a taxon. This may take place in several ways. In the simplest case the taxon disappears from the record and is not replaced. Alternatively, one taxon may replace another, the earlier group consequently disappearing. Thus there is a process of either subtraction or substitution. Extinction generally takes place at particular times and places but there are recurring periods when episodes of mass extinction have taken place. Environmental catastrophe, occurring for whatever reason, removes many groups from the environment and ecosystems collapse. Eventually new forms appear and evolution resumes. It would appear that periods of mass extinction control the pattern of evolution. Geography The end of the existence of a species or group of taxa, or the end of their ability to reproduce. Gaston (2008) PPG 32, 1 observes that rare species are disproportionately vulnerable to extinction in the short term. Loss of a species to chance extinction leaves an area of resource space unoccupied; extinctions could trigger behavioural or evolutionary adaptations (Phillips (2008) PPG 32, 1). Van Kleunen and Richardson (2007) PPG 31, 4 consider the links between species traits and extinction risk and invasiveness. See Kiesling and Aberhan (2007) J. Biogeog. 34, 9 on geographical distribution and extinction risk. Losos and Schluter (2000) Nature 408 explain the relationship as the outcome of the effect of area on immigration and extinction rates. ‘If the twentieth-century question was how to stop extinction, then perhaps the twenty-first-century challenge is how to avoid the total collapse of the biosphere, our life support system’ (W. Adams 2004). See Sanderson et al. (2002) Bioscience 52, 10 on human activity and extinction rates. See also biodiversity crisis.
随便看	Playfair’s axiom play-the-winner rule Plaza Accord PLB PL/C PLC PLCC PLC relation PLD pleasure pleasure principle plebs Plectronoceras cambria Pleiades Pleiades-HR pleiomorphism pleiotropic Pleistocene Pleistocene refugium Pleistogene Plekhanov, Georgi Valentinovich (1857–1918) Plekhanov, Georgy Valentinovich (1856–1918) plenitude, principle of plenum pleochroic