The 56 filters of ~100 A FWHM effectively provide low resolution spectroscopy of all observed objects. This means that J-PAS will generate an impressive amount of data that will be extremely valuable for researchers of all areas of astronomy. This filter system will, for example, allow to measure many parameters which are relevant for the study of the evolution of galaxies: direct stellar temperatures, stellar masses, distribution of stellar ages, metallicity, dust extinction, and interstellar gas emission. The collection of spectro-photometric data of more than 300 hundred million galaxies will allow extensive studies of integrated stellar populations, and, since bright red galaxies will be observed until z~0.9, to investigate the evolution of galaxies from that redshift. This will allow detailed studies of star formation rates, galaxies mergers rates, and chemical evolution that will help understanding the relationship between the stellar components of galaxies of different types and their environments. Furthermore, stellar populations of nearby galaxies will be studied pixel by pixel, allowing us to to investigate the spatial evolution of the stellar component in thousands of galaxies.