  We investigate the evolution of the fractions of late type cluster galaxies
as a function of redshift, using one of the largest, most uniform cluster
samples available. The sample consists of 514 clusters of galaxies in the range
0.02<z<0.3 from the Sloan Digital Sky Survey Cut & Enhance galaxy cluster
catalog. This catalog was created using a single automated cluster finding
algorithm on uniform data from a single telescope, with accurate CCD
photometry, thus, minimizing selection biases. We use four independent methods
to analyze the evolution of the late type galaxy fraction. Specifically, we
select late type galaxies based on: restframe g-r color, u-r color, galaxy
profile fitting and concentration index. The first criterion corresponds to the
one used in the classical Butcher-Oemler analyses. The last three criteria are
more sensitive to the morphological type of the galaxies. In all four cases, we
find an increase in the fraction of late type galaxies with increasing
redshift, significant at the 99.9% level. The results confirm that cluster
galaxies do change colors with redshift (the Butcher-Oemler effect) and, in
addition, they change their morphology to later-type toward higher redshift --
indicating a morphological equivalent of the Butcher-Oemler effect. We also
find a tendency of richer clusters to have lower fractions of late type
galaxies. The trend is consistent with a ram pressure stripping model, where
richer clusters have more effective ram pressure due to their higher
temperature.
