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In this groundbreaking book, Lynn Margulis and Dorion Sagan present an answer to one of the enduring mysteries of evolution -- the source of inherited variation that gives rise to new species. Random genetic mutation, long believed to be the main source of variation, is only a marginal factor. As the authors demonstrate in this book, the more important source of speciation, by far, is the acquisition of new genomes by symbiotic merger. The result of thirty years of delving into a vast, mostly arcane literature, this is the first book to go beyond -- and reveal the severe limitations of -- the "Modern Synthesis" that has dominated evolutionary biology for almost three generations. Lynn Margulis, whom E. O. Wilson called "one of the most successful synthetic thinkers in modern biology," and her co-author Dorion Sagan have written a comprehensive and scientifically supported presentation of a theory that directly challenges the assumptions we hold about the variety of the living world.

Charles Darwin's On the Origin of Species, in which he writes of his theories of evolution by natural selection, is one of the most important works of scientific study ever published. This unabridged edition also includes a rich selection of primary source material: substantial selections from Darwin's other works (Autobiography, notebooks, letters, Voyage of the Beagle, and The Descent of Man) and selections from Darwin's sources and contemporaries (excerpts from Genesis, Paley, Lamarck, Spencer, Lyell, Malthus, Huxley, and Wallace).

Although Charles Darwin's theory of evolution laid the foundations of modern biology, it did not tell the whole story. Most remarkably, The Origin of Species said very little about, of all things, the origins of species. Darwin and his modern successors have shown very convincingly how inherited variations are naturally selected, but they leave unanswered how variant organisms come to be in the first place. In Symbiotic Planet, renowned scientist Lynn Margulis shows that symbiosis, which simply means members of different species living in physical contact with each other, is crucial to the origins of evolutionary novelty. Ranging from bacteria, the smallest kinds of life, to the largest -- the living Earth itself -- Margulis explains the symbiotic origins of many of evolution's most important innovations. The very cells we're made of started as symbiotic unions of different kinds of bacteria. Sex -- and its inevitable corollary, death -- arose when failed attempts at cannibalism resulted in seasonally repeated mergers of some of our tiniest ancestors. Dry land became forested only after symbioses of algae and fungi evolved into plants. Since all living things are bathed by the same waters and atmosphere, all the inhabitants of Earth belong to a symbiotic union. Gaia, the finely tuned largest ecosystem of the Earth's surface, is just symbiosis as seen from space. Along the way, Margulis describes her initiation into the world of science and the early steps in the present revolution in evolutionary biology; the importance of species classification for how we think about the living world; and the way "academic apartheid" can block scientific advancement. Written with enthusiasm and authority, this is a book that could change the way you view our living Earth.

These original contributions by symbiosis biologists and evolutionary theorists address the adequacy of the prevailing neo-Darwinian concept of evolution in the light of growing evidence that hereditary symbiosis, supplemented by the gradual accumulation of heritable mutation, results in the origin of new species and morphological novelty.A departure from mainstream biology, the idea of symbiosis--as in the genetic and metabolic interactions of the bacterial communities that became the earliest eukaryotes and eventually evolved into plants and animals--has attracted the attention of a growing number of scientists.These original contributions by symbiosis biologists and evolutionary theorists address the adequacy of the prevailing neo-Darwinian concept of evolution in the light of growing evidence that hereditary symbiosis, supplemented by the gradual accumulation of heritable mutation, results in the origin of new species and morphological novelty. They include reports of current research on the evolutionary consequences of symbiosis, the protracted physical association between organisms of different species. Among the issues considered are individuality and evolution, microbial symbioses, animal-bacterial symbioses, and the importance of symbiosis in cell evolution, ecology, and morphogenesis. Lynn Margulis, Distinguished Professor of Botany at the University of Massachusetts at Amherst, is the modern originator of the symbiotic theory of cell evolution. Once considered heresy, her ideas are now part of the microbiological revolution. ContributorsPeter Atsatt, Richard C. Back, David Bermudes, Paola Bonfante-Fasolo, René Fester, Lynda J. Goff, Anne-Marie Grenier, Ricardo Guerrero, Robert H. Haynes, Rosmarie Honegger, Gregory Hinkle, Kwang W. Jeon, Bryce Kendrick, Richard Law, David Lewis, Lynn Margulis, John Maynard Smith, Margaret J. McFall-Ngai, Paul Nardon, Kenneth H. Nealson, Kris Pirozynski, Peter W. Price, Mary Beth Saffo, Jan Sapp, Silvano Scannerini, Werner Schwemmler, Sorin Sonea, Toomas H. Tiivel, Robert K. Trench, Russell Vetter