The overall aim of my research programme is the joint application of an array of state-of-the-art techniques in palaeobiology, including Computational Fluid Dynamics (CFD), laser scanning, non-destructive X-ray computed tomography, geometric morphometrics and several tests for macroevolutionary analysis, in order to address the morphological diversity and disparity of early vertebrates from a functional and ecological point of view within temporal and phylogenetic frameworks. The ultimate goal of this research is to elucidate the scenarios in which the major groups of vertebrates emerged and to shed light onto the underlying selective forces that drove the main evolutionary transitions of the group.