  Simulations and observations of galactic bars suggest they do not commonly
evolve into bulges, although it is possible that the earliest bars formed
bulges long ago, when galaxies were smaller, denser, and had more gas. The most
highly evolved of today's bars may become lenses over a Hubble time. Most
galaxies in the early Universe are extremely clumpy, with 10^8-10^9 Msun blue
clumps that resemble in color and magnitude the isolated field objects nearby.
The presence of blue and irregular bars at high redshift suggests that some
bars formed primarily in the gas phase accompanied by giant starbursts, rather
than in pure stellar disks like most models. Secular and non-secular processes
that cause galaxies to evolve are summarized.
