The evolution of viviparity in salamanders (Amphibia, caudata): organization, variation, and the hierarchical nature of the evolutionary process

Abstract

Organization and variability are core concepts in evolutionary biology. Nature is variable, but also highly organized, and this organization is both a consequence and a causality of the evolutionary process. In order to analyze the evolution of phenotypes, the organizational properties of the system studied have to be considered. Here, we analyze under this perspective the evolution in salamanders of a new reproductive strategy, viviparity. We have undertaken distinct approaches to characterize the generation of the novelty at different organizational levels (genes, cells, organism, populations). We highlight the necessity of integrative research programs to account for the complex, dynamic, and hierarchical nature of the evolutionary process.