The quest for the origins in evolutionary biology

Abstract

Abstract. Studying origins in evolutionary biology is an endeavour to reconstruct a chronicle of past events. Traditionally rooted in comparative biology and phylogenetics, these studies can also be conducted with either logical or experimental modelling approaches. The interaction between these two domains of inference -comparative reconstruction of the evolutionary past and modeling/experimenting the evolutionary process -must be encouraged. In both domains, the study of origins needs to be carefully designed to take into account anterior evolutionary stages on which they could depend. Comparative biology and past reconstruction must be performed on simple observational data (natural kinds), not on artificial general classes. And finally, understanding causality relationships calls for correlation approaches that must be optimized with regard to the number of natural replicates.The term "origin" is often employed when studying how some living organisms or their main characteristics appeared, or even how Life itself appeared. This term is generally considered as unambiguous [1], as it refers to very closely interrelated aspects: the early stage after which the organism or the characteristic appeared, the process that gave rise to the organism and its characteristics, the transition event between the anterior state and the state where the characteristic had already occurred, or even the characters in the anterior stage that allowed the emergence of the feature studied. This quest for the origins -a theme central to evolutionary biology -is a way to focus on special moments of evolution when some critical events occurred. It allows understanding evolutionary transitions that led to either large diversifications or to major qualitative changes and new evolutionary trajectories. This quest is traditionally rooted in systematic, comparative and paleontological studies. Yet many modeling or experimental approaches also strongly contribute to this field.The present book deals with methodological accounts or case studies at very diverse levels and scales in varied scientific domains of comparative or experimental evolutionary biology. It exemplifies how very different studies finally point to the same kind of prospects, depend on the same general methodological requirements and open similarly wide perspectives. These chapters are issued from the contributions presented during two workshops organized by the authors at the Institut de Systématique, Evolution, Biodiversité (Muséum national d'Histoire naturelle, Paris) in 2013 and 2014. These workshops were intended to provide a room for discussion about the study of origins, a