Evolution of the Digestive System

The capability of cells to uptake and digest molecules to acquire energy is essential for all life forms. During evolution, with the emergence of multicellularity, specialized cell types and organs became responsible for acquiring food particles, breaking them down and absorbing nutrients. This had a significant impact on the evolution of animal diversity: it is due to the invention of extracellular digestion if the animal body was released from size limit constraints.

The complexity and shapes of guts vary among animals, but they all form through a highly conserved mechanism in development called gastrulation. During gastrulation, germ layers are specified and a through gut forms and differentiates into a fore-, a mid- and a hind-gut, each one dedicated to specific functions in digestion.

This book explores the evolutionary history of the animal digestive systems, highlighting their broad diversification and their conserved features in animals belonging to different branches of the tree of life. Gut development is explained by entraining molecular mechanisms underlying this process. An international team of contributors offer a close look at the extraordinary complexity of the gut endocrine system, dig into the gut-brain axis and the gut immune responses, and describe the function and evolution of the gut microbiome.