The (bit buzzwordy) name for organisms that live in 'extreme' conditions. Since this extremeness is only defined by what we like it is somewhat relative. However, it is true to say that most types of life live in mesophillic conditions of 30° Centigrade, low salt, low pressure environments. Some argue that large amounts of biomass exist in the subsurface regions in the deep hot biosphere, and some calculations suggest that more life exists below the surface than on top (measured in terms of weight). Here are some types of extremophile: When first encountered, some of these organisms helped to reconstruct the classification system for life. Indeed, some have even used their abilities as justification for extraterrestrial life, although not in the form of bug eyed aliens as such. Amazingly, some soil bacteria survived a long trip on a space probe - which suggests that life could spread between planets.

Most of the known extremophiles are microorganisms, although there are a few exceptions, such as the larger plants and animals that live in the superheated waters near volcanic vents on the floors of the oceans.

See also: archaea and extremozyme.