  Recent observations suggest that dwarf galaxies pervade the universe, for
they have been encountered in large numbers in all the environments. However,
we present evidence that suggests dwarf galaxies may be subject to strong
dynamical processes in high density environments, the combined effects of
multiple encounters and the tidal effects due to the potential well of rich
clusters could result in the effective disruption of dwarf galaxies in the
clusters' central regions. Alternatively, the lack of dwarf galaxies in rich
environments has been interpreted in terms of a "density-morphology relation":
dwarf galaxies prefer low density environments (Phillipps et al. 1998). We
argue that such an explanation cannot account for the relationship between the
cD halo luminosity and the gas mass in the ICM, whereas the dwarf disruption
scenario proposed by Lopez-Cruz et al. (1997) addresses this naturally.
