"This is a serious, excellent piece of science writing ... Bratman's prose captures the core idea and gives a faithful rendering for a non-specialist audience" - Eric Smith, PhD. Coauthor of The Origin and Nature of Life: The Emergence of the Fourth Geosphere. Just as detectives are reluctant to believe in coincidences, scientists don't usually base their theories on lucky accidents. However, the standard "RNA-first" explanation of the origin of life does just that: It invokes the chance formation of RNA molecules that catalyzed their own replication and kicked off Darwinian evolution at one go. RNA-first does not provide any explanation of where the precursors of RNA would come from nor what processes would raise their chemical concentrations to levels high enough to produce appreciable quantities of RNA. The "metabolism-first" theory of life's origins presented in this book takes a different approach. It argues that the biosphere was a likely outcome of conditions on the early Earth. It regards life as a chemical process driven into existence by an unresolved energy differential in undersea hydrothermal vents. If this analysis is correct, any planet with tectonic activity and liquid oceans would expected to grow a biosphere too. Many decades ago, Harold Morowitz noted that when energy flows through a system, it often restructures that system in such a way that more energy can flow through it. Metabolism-first takes this observation as a primary insight and proposes that autocatalytic processes progressively enhanced energy flow through the complex chemistry of hydrothermal vents. This modified vent chemistry became the chemistry of metabolism and still exists today in the core metabolic processes that drive all of life. RNA emerged later as an autocatalytic component of that driven chemistry. Only then did the Darwinian era begin. The text includes diagrams, a glossary and an index.
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