The hour-long program helps viewers understand how all living things today, from bacteria to blue whales, are related and why this knowledge is valuable, both practically and philosophically. We humans are not a species apart, but an integral facet of a biological continuum. The giant glass and steel structure was to be self-sustaining, but soon after it was sealed off, the oxygen level began to drop and species began slowly to disappear. Scientists discovered that the answer lies in part with microbes. The Biosphere's designers had failed to recognize that the planet's tiniest organisms played such an essential role in the complex ecosystems they created.
Scientists seek answers in a lush Costa Rican rain forest and in the oceans.
Their discoveries tell us that in the web of life, microbes provide the wiring. The failed experiment in Biosphere 2 provides a stunning reminder of the need to understand unseen life on our planet. Microbes, not man, are the true masters of earth's balance. . The third episode looks at the remarkable interaction between microbes and the humans they call home. In the American Southwest, doctors recall the sober lessons of the hantavirus outbreak, a model of possible future viral outbreaks.