  Using the technique of Angulo & White (2010) we scale the Millennium and
Millennium-II simulations of structure growth in a LCDM universe from the
cosmological parameters with which they were carried out (based on first-year
results from the Wilkinson Microwave Anisotropy Probe, WMAP1) to parameters
consistent with the seven-year WMAP data (WMAP7). We implement semi-analytic
galaxy formation modelling on both simulations in both cosmologies to
investigate how the formation, evolution and clustering of galaxies are
predicted to vary with cosmological parameters. The increased matter density
Omega_m and decreased linear fluctuation amplitude sigma8 in WMAP7 have
compensating effects, so that the abundance and clustering of dark halos are
predicted to be very similar to those in WMAP1 for z <= 3. As a result, local
galaxy properties can be reproduced equally well in the two cosmologies by
slightly altering galaxy formation parameters. The evolution of the galaxy
populations is then also similar. In WMAP7, structure forms slightly later.
This shifts the peak in cosmic star formation rate to lower redshift, resulting
in slightly bluer galaxies at z=0. Nevertheless, the model still predicts more
passive low-mass galaxies than are observed. For rp< 1Mpc, the z=0 clustering
of low-mass galaxies is weaker for WMAP7 than for WMAP1 and closer to that
observed, but the two cosmologies give very similar results for more massive
galaxies and on large scales. At z>1 galaxies are predicted to be more strongly
clustered for WMAP7. Differences in galaxy properties, including, clustering,
in these two cosmologies are rather small up to redshift 3. Given that there
are still considerable residual uncertainties in galaxy formation models, it is
very difficult to distinguish WMAP1 from WMAP7 through observations of galaxy
properties or their evolution.
