Left panels: percentage contributions of young t< 140 Myr, intermediate (140 Myr <t< 1.4 Gyr) and old t> 1.4 Gyr stellar populations to the observed light at 5635 Å. Right panel: radial profiles of the light contributions from young x_Y (blue), intermediate x_I (green) and old populations x_O (red) with the radial distance in HLR and kpc. For comparison, the dashed lines with the same colors are the profiles for Sbc spiral galaxies from CALIFA.