Symbiosis, the sustained and intimate associations between unrelated life forms, is now recognized as a ubiquitous phenomenon, one that has shaped evolution since the origin of life and that continues to affect all species. This Very Short Introduction begins with a brief history of relevant early discoveries, and considers why symbiosis was so long neglected as a respectable topic of biological research and why it was a controversial topic. Nancy Moran explores the fundamental drivers that lead to symbiotic associations, the evolutionary stability of symbiotic partnerships, and the origin of the complex (eukaryotic) cell. Moran also examines molecular approaches, explaining how they sparked discovery of previously unknown symbionts, including those in our own bodies.
