A distinguished microbiologist explains the importance of the symbiosis - where different organisms contribute to each other's support - and how this is changing our view of life on Earth. Lynn Margulis is an ardent supporter of the Gaia hypothesis: the idea that due to the finely balanced interdependence of all life forms, the planet functions as a single , giant cell. Margulis argues that no organism is an island and that all are linked to each other. The Symbiotic Planet traces the evolution of planet earth from the origins of life and of sex to the emergence of 'hyperseas' and eerie future she describes for humanity.