  We suggest that the growth of the central black hole in active galactic
nuclei (AGN) due to the matter accreted over the AGN lifetime causes an
evolution of the luminosity and spectrum. In a previous paper we have shown
that the effective temperature of the UV continuum spectrum and the
emission-line equivalent width are anti-correlated with the black-hole mass.
Here we estimate the change in the equivalent width of the emission lines due
to the growth of the black hole mass caused by the accreted material and show
that for several plausible accretion scenarios and effective-temperature models
the evolving equivalent width is anti-correlated with continuum luminosity,
implying that intrinsic evolution could contribute to the Baldwin effect.
