Biospheres: Metamorphosis of Planet Earth

Biospheres are self-contained ecological environments, ranging from laboratory-bred bacteria colonies to the Soviet Bios project involving prototypes of interplanetary spaceships. Coauthor with Lynn Margulis of Micro cosmos , Sagan takes a close look at Biosphere II, a sealed metal-and-glass terrarium for animals, plants and humans now under construction near Tucson, Ariz. Criticized by some as technocratic Disneylands or elitist retreats, biospheres are defended here as bulwarks against an increasingly polluted world, as experimental laboratories and even as confirmation of British chemist James Lovelock's Gaia hypothesis, which views planet Earth as a single, live, self-regulating organism. Sagan's convoluted futurist tract is most useful for its sifting of evidence for the Gaia hypothesis from diverse areas--the behavior of termites, atmospheric science, genetics, etc. (Mar.)