The new panoramic detectors on large telescopes as well as the most performing space missions allowed us to complete large surveys of the Universe at different wavelengths and thus study the relationships between the different galaxy components at various epochs. At the same time, the increasing computing power allowed us to simulate the evolution of galaxies since their formation at an angular resolution never reached so far. In this article I will briefly describe how the comparison between the most recent observations and the predictions of models and simulations changed our view on the process of galaxy formation and evolution.