Modular evolution: how natural selection produces biological complexity

Evolutionary biology is a fascinating field with a degree of conceptual complexity that is unique among the biological sciences. As such, many biology students may find that discussions of evolutionary biology tend to wax esoteric and become almost philosophical. This can make the details of the discipline seem aimless or wandering to uninitiated readers. Such issues will not be a problem for readers of Modular Evolution. Modular Evolution has a refreshingly narrative structure. It begins with fundamental discussions of the nature of evolutionary biology and covers relevant debates from the evolution of multicellularity to the basis of human culture. Each chapter introduction artfully sets the stage, biologically and historically, with the subject discussed in a flowing, chronological fashion. The conclusions generally summarize the material and introduce the reader to the next chapter. The material is discussed in an engaging fashion with examples that are typically crisp and simple. Moreover, the narrative structure enables the reader to follow the development of ideas, thus facilitating understanding of a concept. Unfortunately, the book could benefit from more diagrams. For example, Drosophila embryogenesis is discussed in the context of the evolution of development, but the process of embryogenesis is difficult to envision from a strictly verbal description. In such instances, the book would benefit from illustration. Those diagrams that are included, however, are clear, informative, and well integrated. The author does not shy away from the nature of biological complexity. Notably, he does not settle for the Biological Unit Concept, which focused on the aggregation of biological units into interdependent “superunits,” but instead presents his own. He defines biological complexity as having a basis in “Schroedinger’s principle of Order from Order,” such that each carrier of modular information produces a disposable phenotype for selection to act upon, which can itself evolve into an information carrier, creating hierarchal levels of information. Based on this, the complexity of an organism should be determined by the number of levels in which information is stored. Organisms with both a genetic and developmental code (multicellular organisms) are more complex than organisms with only a genetic code (unicellular organisms). The author’s model is dependent on the modular nature of information encoded at each level of organization. Yet although the author mentions information modularity throughout the book, the importance of information modularity is not demonstrated emphatically enough. An instructor with this book should consider spending time with students solidifying its importance. Altogether, Modular Evolution is a fascinating book that dives into current topics in evolutionary biology while offering an intriguing framework for understanding biological complexity. The author also presents enough evidence to invite a lively critical analysis of this framework by students. Finally, the cover of this book is startling but apt. It features a Lego man tearing open his chest to reveal more Legos inside. Legos are discrete building blocks ― modules themselves. This immensely complex organism is made not from a continuum of structures, but a collection of modules.