  We use a new fiber spectroscopic survey of 12 nearby, poor groups of galaxies
to examine the dynamics and evolution of galaxies in these common, but poorly
studied, environments. Some of our conclusions are: (1) The nine groups in our
sample with diffuse X-ray emission are in fact bound systems with at least
20-50 group members with absolute magnitudes as faint as M_B ~ -14 + 5 log h.
(2) Galaxies in each X-ray-detected group have not all merged together because
a significant fraction of the group mass lies outside of the galaxies and in a
common halo, thereby reducing the rate of galaxy-galaxy interactions. (3) The
similarity of the recent star formation histories and the fraction of early
type galaxies in some poor groups to those in rich clusters suggests that
cluster-specific environmental effects may not play a dominant role in the
recent evolution of cluster galaxies. The evolution of group and cluster
members may be driven instead by galaxy-galaxy interactions, which are likely
to occur with equal frequency in field groups and in groups that have recently
fallen into clusters (i.e., subclusters).
