Top panels: dwarf galaxies g − r colors as a function of the r-band mean effective surface brightness. Evolutionary tracks of single stellar population for a Kroupa-like IMF for different metallicities are shown. The crosses on each track correspond to 0.5, 1, 2, 3, …, 13, 14 Gyr. Horizontal lines show the 4 Gyr age level of each track. Lower panels: galaxies Sérsic indices n as a function of their colors. Galaxies are split in three luminosity bins, represented by the different columns. In each panel is reported the ρ value of the corresponding Spearman’s correlation test, and its error.