John Tyler Bonner, one of our most distinguished and insightful biologists, here challenges a central tenet of evolutionary biology. In this concise, elegantly written book, he makes the bold and provocative claim that some biological diversity may be explained by something other than natural selection.
With his customary wit and accessible style, Bonner makes an argument for the underappreciated role that randomness – or chance – plays in evolution. Due to the tremendous and enduring influence of Darwin's natural selection, the importance of randomness has been to some extent overshadowed. Bonner shows how the effects of randomness differ for organisms of different sizes, and how the smaller an organism is, the more likely it is that morphological differences will be random and selection may not be involved to any degree. He traces the increase in size and complexity of organisms over geological time, and looks at the varying significance of randomness at different size levels, from microorganisms to large mammals. Bonner also discusses how sexual cycles vary depending on size and complexity, and how the trend away from randomness in higher forms has even been reversed in some social organisms.
Certain to provoke lively discussion, Randomness in Evolution is a book that may fundamentally change our understanding of evolution and the history of life.
John Tyler Bonner is professor emeritus of ecology and evolutionary biology at Princeton University. His books include The Social Amoebae: The Biology of Cellular Slime Molds and Why Size Matters: From Bacteria to Blue Whales.
"John Tyler Bonner, a distinguished developmental biologist, has long argued that a major driving force in the evolution of complexity is natural selection for large size. Here he takes a radically different view to explain the diversity of form among eukaryotic microorganisms: randomness, not selection, rules their lives. This stimulating and provocative theme is explored with ideas from a variety of fields. It simultaneously introduces students to the nature of a debate on the causes of diversity."
– Peter R. Grant, coauthor of How and Why Species Multiply: The Radiation of Darwin's Finches
"Bonner makes a compelling case that the morphology of microorganisms is governed not by natural selection but by chance. He could be right. But right or wrong, this claim will be hugely controversial. It doesn't just 'approach heresy,' as he puts it. It is heresy."
– Dan McShea, Duke University
"The main point of Bonner's book is that the importance of randomness in evolution depends on size. What is new is the claim that small organisms are more likely to have selectively neutral morphological variation. This, if true, is very interesting and important. Randomness in Evolution is provocative and will lead to lively discussion."
– Michael Foote, University of Chicago