  Surface brightness evolution has been detected in elliptical galaxies
(consistent with passive evolution models of old stellar populations) and in
disk galaxies (presumably due to enhanced star-formation rates). The rates of
evolution in clusters and the field are not measurably different. In addition
to this similarity, the high-redshift populations in both environments exhibit
a ``blue-excess'' population, increased rates of star formation, and high
frequency of peculiar structure. Thus, there are several parallels between
evolving cluster and field galaxies and the high-redshift cluster environment
will be understood only by comparison with the field population at the same
epoch.
