Median evolution of the mass fractions of the high-mass (red stars) and low-mass (blue triangles) galaxies of the sample. The dashed lines represent the 68% intervals, and the individual tracks of each source (as in Fig. 16) are shown in the background in gray. We can see that the high-mass sources reach their half-mass by z ~ 2, while for the low-mass ones this happens close to z ~ 1.