<P> Most known extremophiles are microorganisms . The domain Archaea contains renowned examples , but extremophiles are present in numerous and diverse genetic lineages of bacteria and archaeans . Furthermore , it is erroneous to use the term extremophile to encompass all archaeans , as some are mesophilic . Neither are all extremophiles unicellular ; protostome animals found in similar environments include the Pompeii worm , the psychrophilic Grylloblattidae ( insects ) and Antarctic krill ( a crustacean ) . Many would also classify tardigrades ( water bears ) as extremophiles but while tardigrades can survive in extreme environments , they are not considered extremophiles because they are not adapted to live in these conditions . Their chances of dying increase the longer they are exposed to the extreme environment . </P>
<P> Most known extremophiles are microorganisms . The domain Archaea contains renowned examples , but extremophiles are present in numerous and diverse genetic lineages of bacteria and archaeans . Furthermore , it is erroneous to use the term extremophile to encompass all archaeans , as some are mesophilic . Neither are all extremophiles unicellular ; protostome animals found in similar environments include the Pompeii worm , the psychrophilic Grylloblattidae ( insects ) and Antarctic krill ( a crustacean ) . Many would also classify tardigrades ( water bears ) as extremophiles but while tardigrades can survive in extreme environments , they are not considered extremophiles because they are not adapted to live in these conditions . Their chances of dying increase the longer they are exposed to the extreme environment . </P>
which domain includes organisms that require extreme environmental conditions for survival
which domain includes organisms that require extreme environmental conditions for survival
Archaea
Archaea