The Major Transitions in Evolution

Maynard Smith and Szathmáry identify the handful of moments in the history of life when the fundamental unit of biological organisation changed: the origin of replicating molecules, the emergence of chromosomes, the transition from RNA to DNA, the eukaryotic cell, sexual reproduction, multicellularity, animal societies, and human language. Their unifying argument is that each transition involved a change in how information is stored, transmitted, or interpreted — making evolutionary history fundamentally an information-processing story. The book is technically demanding, drawing on genetics, game theory, and molecular biology, but the framework it establishes is extraordinarily powerful: it connects the origin of the genetic code to the origin of language through a single explanatory lens. It reshaped how evolutionary biologists think about the hierarchy of life and remains essential for anyone interested in the deep relationship between information and biological complexity.