  We intend to show that it is possible to derive the physical parameters of
galaxies from their broad-band spectral energy distribution out to a redshift
of 1.2. This method has the potential to yield the physical parameters of all
galaxies in a single field in a homogeneous way. We use an extensive dataset,
assembled in the context of the VVDS survey, which reaches from the UV to the
IR and covers a sample of 84073 galaxies over an area of 0.89 deg$^2$. We also
use a library of 100000 model galaxies with a large variety of star formation
histories (in particular including late bursts of star formation). We find that
we can determine the physical parameters stellar mass, age and star formation
rate with good confidence. We validate the star formation rate determinations
in particular by comparing it to a sample of spectroscopically observed
galaxies with an emission line measurement. We use our sample to build the
number density function of galaxies as a function of stellar mass, specific
star formation rate and redshift. We then study whether the stellar mass
function at a later time can be predicted from the stellar mass function and
star formation rate distribution at an earlier time. We find that the predicted
growth in stellar mass from star formation agrees with the observed one.
However, the predicted stellar mass density for massive galaxies is lower than
observed, while the mass density of intermediate mass galaxies is
overpredicted. When comparing with a direct measurement of the major merger
rate from the VVDS survey we find that major mergers are sufficient to explain
about a third of the mass build-up at the massive end, while the rest is likely
contributed through minor mergers.
