  We present cosmological hydrodynamic simulations performed to study evolution
of galaxy population. The simulations follow timed release of mass, energy, and
metals by stellar evolution and employ phenomenological treatments of supernova
feedback, pre-supernova feedback modeled as feedback by radiation pressure from
massive stars, and quenching of gas cooling in large halos. We construct the
fiducial model so that it reproduces the observationally estimated galaxy
stellar mass functions and the relationships between the galaxy stellar mass
and the host halo mass from $z = 4$ to 0. We find that the fiducial model
constructed this way naturally explains the cosmic star formation history, the
galaxy downsizing, and the star formation rate and metallicity of the
star-forming galaxies. The simulations without the quenching of the gas cooling
in large halos overproduce massive galaxies at $z < 2$ and fail to reproduce
galaxy downsizing. The simulations that do not employ the radiation pressure
feedback from young stars predict too strong redshift evolution of the
mass-metallicity relation. Furthermore, the slope of the relation becomes too
steep at low redshift without the radiation pressure feedback. The metallicity
dependence in the radiation pressure feedback is a key to explain the observed
mass-metallicity relation. These facts indicate that these two processes in
addition to supernova feedback are essential for galaxy evolution. Our simple
phenomenological model is suitable to construct a mock galaxy sample to study
physical properties of observed galaxy populations.
