This image is a color-density plot of the dark matter distibution in a 12 million particle simulation of a Fornax cluster (courtesy F. Governato). We are going to resimulate this dark matter only cluster (completed by F. Governato and L. Mayer) at higher resolution by replacing the 20 most massive halos and a sample of 30 dwarf sized halos with realistic galaxy models at the epoch of their cluster infall. The galaxy replacements are very high resolution star+dark matter bulge/halo/disk models based on the GALFORM semi-analytic model (Cole et al 2000). The resulting simulation (with 20 million particles by z=0) will capture the dynamical evolution of the cluster stars (both bound and unbound) with excellent detail and realism. We will use the results of this simulation to help understand the effect of the galaxy cluster environment on the evolution of galaxies. In particular, we will study i) the morphological evolution of a wide dynamic range of galaxies and ii) the origin and evolution of intracluster stars, and compare our results with observational data on nearby clusters.