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 innovation had a profound impact on animal evolution: the emergence of extracellular digestion released organisms from size constraints and enabled the diversification of complex body plans. The complexity and morphologies of guts vary among animals, yet they all form through a highly conserved developmental process known as 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 animal digestive systems, highlighting both their extraordinary diversification and their conserved features across distant branches of the tree of life. An international team of contributors offers a close look at the molecular and developmental mechanisms underlying gut formation and evolution, as well as the origins and diversification of endocrine and exocrine gut functions, dig into the function and evolution of the gut microbiome and describe the regenerative capacities of the gastrointestinal tract.

Rossella Annunziata is a Researcher in the Department of Biology and Evolution of Marine Organisms - Stazione Zoologica Anton Dohrn in Napoli, Italy. She received her PhD in Molecular Biology from the Open University of London. She has authored or co-authored numerous peer review scholarly articles and protocols.

Maria I. Arnone is a Senior Scientist at the Stazione Zoologica Anton Dohrn, Napoli, Italy. She received her PhD in Biochemistry from the Università degli Studi di Napoli Federico II, Napoli. She has authored or co-authored dozens of peer review scholarly articles and book chapters.