WordNet (r) 3.0 (2006):

biosphere
    n 1: the regions of the surface and atmosphere of the Earth (or
         other planet) where living organisms exist

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "biosphere":
   Earth, Gaea, Ge, Tellus, Terra, aerosphere, all that lives,
   atmosphere, biochore, biocycle, biota, biotope, brawn, ecosphere,
   fiber, flesh, flora and fauna, gaseous envelope, geography,
   geosphere, globe, lift, living matter, living nature, mother earth,
   noosphere, organic matter, organic nature, organized matter, plasm,
   terra, terrestrial globe, the blue planet, this pendent world,
   tissue, vale, vale of tears, welkin, whole wide world, world