  We use cosmological SPH simulations to investigate the effects of mergers and
interactions on the formation of the bulge and disc components of galactic
systems. We find that secular evolution during mergers seems to be a key
process in the formation of stable disc-bulge systems with observational
counterparts and contributes to establish the fundamental relations observed in
galaxies. Our findings suggest that the secular evolution phase couples the
formation mechanisms of the bulge and disc components. According to our
results, depending on the particular stability properties and merger
parameters, violents events could drive a morphological loop in which the
outcome could be a disc or a spheroid.
