
Extremophile
A rather chauvinistic term for any biological organism, whether Terragen or xenobiont, natural or tweaked, that requires extreme (non-Earthlike) environments for growth or metabolism; e.g. high temperature, acidity, pressure, radiation, toxic compounds, vacuum or near-vacuum, etc. There are extremophile sophont clades in the Terragen Sphere which inhabit cold temperature worlds, high temperature worlds, hi-radiation worlds, vacuum environments, and other environments which would would be fatal to nearbaseline humans.

- Acidophile - Text by M. Alan Kazlev
An organism with a pH optimum for growth at, or below, pH 3. A type of extremophile.
- Alkaliphile - Text by M. Alan Kazlev
An organism with optimal growth at pH values above 10. A type of extremophile.
- Barophile - Text by M. Alan Kazlev
An organism that lives optimally at high hydrostatic pressure. A type of extremophile.
- Halophile - Text by M. Alan Kazlev
An organism requiring high concentrations of salt for growth or optimal metabolism. A type of extremophile.
- Hyperthermophile - Text by M. Alan Kazlev
An organism having a growth temperature optimum of 80°C or higher. A type of extremophile.
- Psychrophile - Text by M. Alan Kazlev
An organism that requires or prefers cold for growth and metabolism. A type of extremophile. Common on some Europan planets and moons; in rare instances even evolve an intelligent star-faring civilization (the Muuh being the only known current example).