  Increasingly large populations of disk galaxies are now being observed at
increasingly high redshifts, providing new constraints on our knowledge of how
such galaxies evolve. Are these observations consistent with a cosmology in
which structures form hierarchically? To probe this question, we employ
SPH/N-body galaxy scale simulations of late-type galaxies. We examine the
evolution of these simulated disk galaxies from redshift 1 to 0, looking at the
mass-size and luminosity-size relations, and the thickness parameter, defined
as the ratio of scale-height to scale-length. The structural parameters of our
simulated disks settle down quickly, and after redshift z=1 the galaxies evolve
to become only slightly flatter. Our present day simulated galaxies are larger,
more massive, less bright, and redder than at z=1. The inside-out nature of the
growth of our simulated galaxies reduces, and perhaps eliminates, expectations
of evolution in the size-mass relation.
