How the Snake Lost Its Legs fly embryo. His books on evolutionary developmental biology (evo-devo) include "Imaginal Discs: The Genetic and Cellular Logic of Pattern Formation" (2002), "Quirks of Human Anatomy: An Evo-Devo Look at the Human Body" (2009), and "Deep Homology? Uncanny Similarities of Humans and Flies Uncovered by Evo-Devo" (2017). In Held's view, "Quirks", "Snake", and "Deep Homology" form a trilogy on evo-devo. "How the Snake Lost Its Legs" is ostensibly organised into six chapters, but in effect into three parts. The first chapter serves as an introduction and overview. The next four chapters provide what Held calls "the meatier aspects of evo-devo" with
Innovation butterfly Innovation butterfly The innovation butterfly is a metaphor that describes how seemingly minor perturbations (disturbances or changes) to project plans in a system connecting markets, demand, product features, and a firm's capabilities can steer the project, or an entire portfolio of projects, down an irreversible path in terms of technology and market evolution. The metaphor was developed by researchers Anderson and Joglekar. It was conceived as a specific instance of the more general 'butterfly effect' encountered in chaos theory. The innovation butterfly arises because many innovation systems are made up of a large number of elements that interact with each