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. Biology is the science of life (from the Greek words bios = life and logos = reasoned account). ... An adjective is a part of speech which modifies a noun, usually making its meaning more specific. ... In biology, a species is a kind of organism. ... The word indigenous is derived from the latin word indigena, meaning nativ, indigenous, aboriginal, and has several, related meanings: The native people of a place; see the article indigenous people. ... This article is about the ecological meaning of endemic. See also endemic (epidemiology). ... In ecology, an ecosystem is a naturally occurring assemblage of organisms (plant, animal and other living organisms—also referred to as a biotic community or biocoenosis) living together with their environment (or biotope), functioning as a unit of sorts. ... This snapping turtle is trying to make a meal of a Canada goose, but the goose is too wary. ... Marine biology is the study of animal and plant life within saltwater ecosystems. ... Ballast may mean: track ballast: gravel or cinders forming the railroad or railway track-bed on which sleepers (ties) and track is laid, for proper drainage ships ballast: water, sand, rocks, or bricks used to weight a ship down when it has very little cargo (though water may contain... The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the north and the Tropic of Capricorn in the southern hemisphere. ... The term habitat has a number of unrelated meanings: A concept in Ecology: see habitat. ... Global mean surface temperatures 1856-2004 Global warming is a term used to describe an increase over time of the average temperature of Earths atmosphere and oceans. ...

See also

• Introduced species
• Invasive species