Top: median mass fraction at z = 0 acquired via gas accretion (black line), “cold mode” galaxy mergers within haloes with (blue line), or “hot-mode” ones within haloes with (red line). Error bars show the interquartile range. The green vertical dashed line shows the baryonic mass m_crit = f_bM_shock. Middle: same as top panel, but for galaxies with f_merg ≥ 0.4 (comparable to ellipticals, see next panel). Bottom: fraction of galaxies with f_merg ≥ f_m for f_m = 0.4, 0.5, and 0.6. The dark red circles show the fraction of ellipticals, as visually classified by Fukugita et al. (2007) from SDSS images, as a function of stellar mass, as presented by Bernardi et al. (2010, middle right panel of their Fig. 12).