The forwards approach to galaxy formation and evolution is extremely powerful
but leaves several questions unanswered. Foremost among these is the origin of
disks. A backwards approach is able to provide a more realistic treatment of
star formation and feedback and provides a practical guide to eventually
complement galaxy formation ab initio.Comment: 11 pages with 2 figures, to appear in "After the Dark Ages: When
Galaxies were Young", proceedings of the 9th annual October Astrophysics
Conference, ed. S. Holt and E. Smith, simulated images available at
http://astro.berkeley.edu/~bouwens/simulation.htm