Alien Guide, Meaning , Facts, Information and Description
- For the 1979 movie, see Alien (movie).
- For live organisms which are not from Earth, see Extraterrestrial_life''
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2 Fiction and conspiracies 3 Law 4 Computing 5 See also 6 External link 7 Further reading |
Biology
In biology the adjective alien, as in alien species, means that the normal locale is somewhere else, that a species or specimen exceptionally has been established in the area in question. Words with similar meaning in biology include exotic, adventive, introduced, and naturalized. These terms contrast with terms as indigenous and endemic. Alien species can sometimes wreak havoc on their new ecosystem, since in many cases, the local predators do not hunt them and so they will have no natural enemy. In some cases, people deliberately also introduced the matching predator, with equally disastrous effects. Introducing of alien species must therefore be prevented as much as possible. This can be difficult. Many marine species travel thousands of kilometers in the ballast water of ocean vessels, which are emptied at the destination port, other lifeforms with their cargo. People also often buy tropical animals and then discover that it is difficult to keep them and release them into the wild. In recent years, tropical species have been moving to the north and south of their original habitat which is attributed to global warming.
Fiction and conspiracies
In popular fiction and conspiracy theories, alien is a term that is often used to refer to life forms, especially intelligent life forms, that are of extraterrestrial origin, i.e. not coming from the Earth. Prime examples of how aliens are viewed are found in the movies Alien, E.T. the Extra-Terrestrial, Signs, and Independence Day.
A peculiarity of this usage is its ethnocentricity: when humans in fictional accounts accomplish interstellar travel and land on a planet elsewhere in the universe, the local inhabitants of these other planets are usually still referred to as "alien," even though they are the native life form and the humans are the intruders. In general they are seen as unfriendly life forms. This may be seen as a reversion to the classic meaning of "alien" as referring to "other," in contrast to "us" in the context of the writer's frame of reference.
Law
In law, an alien is a foreigner who is not a citizen of the land in which he lives. If they live there, as opposed to being just a visitor, they may be called a "resident alien". The term illegal alien describes foreign nationals who have entered the country illegally.
See also: Foreigner, Immigration, Naturalization,
Computing
Alien is a computer program that converts between different Linux package distribution file formats. It supports conversion between Linux Standard Base, RPM, deb, Stampede (.slp) and Slackware (tgz) packages.
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External link
Further reading
