  Star clusters are observed to form in a highly compact state and with low
star-formation efficiencies, and only 10 per cent of all clusters appear to
survive to middle- and old-dynamical age. If the residual gas is expelled on a
dynamical time the clusters disrupt. Massive clusters may then feed a hot
kinematical stellar component into their host-galaxy's field population thereby
thickening galactic disks, a process that theories of galaxy formation and
evolution need to accommodate. If the gas-evacuation time-scale depends on
cluster mass, then a power-law embedded-cluster mass function may transform
within a few dozen Myr to a mass function with a turnover near 10^5 Msun,
thereby possibly explaining this universal empirical feature. Discordant
empirical evidence on the mass function of star clusters leads to the insight
that the physical processes shaping early cluster evolution remain an issue of
cutting-edge research.
