  We follow the evolution of the galaxy population in a Lambda-CDM cosmology by
means of high-resolution N-body simulations in which the formation of galaxies
and their observable properties are calculated using a semi-analytic model. We
display images of the spatial distribution of galaxies in the simulations that
illustrate its evolution and provide a qualitative understanding of the
processes responsible for various biases that develop. We consider three
specific statistical measures of clustering at z=1 and z=0: the correlation
length (in real- and redshift-space) of galaxies of different luminosity, the
morphology-density relation and the genus curve of the topology of galaxy
isodensity surfaces. For galaxies with luminosity below L*, the z=0 correlation
length depends very little on the luminosity of the sample, but for brighter
galaxies it increases very rapidly, reaching values in excess of 10Mpc/h. The
"accelerated" dynamical evolution experienced by galaxies in rich clusters,
which is partly responsible for this effect, also results in a strong
morphology-density relation. Remarkably, this relation is already
well-established at z=1. The genus curves of the galaxies are significantly
different from the genus curves of the dark matter but this is not due to
genuine topological differences but rather to the sparse sampling of the
density field provided by galaxies. The predictions of our model at z=0 will be
tested by forthcoming data from the 2dF and Sloan galaxy surveys, and those at
z=1 by the DEEP and VIRMOS surveys.
