Dorsal closure, an essential stage of Drosophila morphogenesis, provides a model system for tissue dynamics. Our research approach is based on modern genetics, in vivo imaging, laser microsurgery, digital image processing, and quantitative modeling to identify the mechanical forces that connect the genetic program of development to morphogenesis. Key to the dynamics of dorsal closure are four biological processes, involving three tissues, that are coordinated in space, synchronized in time, and remarkably resilient both to genetic perturbations and to laser perturbations. These processes can upregulate in response to laser perturbation, where there are spatial, kinematic, and dynamic asymmetries associated with upregulation. There also are asymmetries observed during non-perturbed, wild type closure, which are associated with the failure of dorsal closure in several mutant embryos. We are quantitatively characterizing emergent properties during dorsal closure, i.e., a velocity governor and the apparent coordination and synchronization of cell activities for these tissues. Peralta et al. Upregulation of forces and morphogenic asymmetries in dorsal closure during Drosophila development. Biophysical Journal 92: 2583-2596 (2007). Kiehart et al. 2005. Ultraviolet Laser Microbeam for Dissection of Drosophila Embryos. In Cell Biology: A Laboratory Handbook, Third Edition. J. E. Celis, editor. Elsevier, San Diego. 87-103 (2005). Franke et al. Nonmuscle myosin II generates forces that transmit tension and drive contraction in multiple tissues during dorsal closure. Curr Biol. 15: 2208-2221 (2005). Hutson et al. Forces for morphogenesis investigated with laser microsurgery and quantitative modeling. Science 300: 145-149 (2003). Kiehart et al. Multiple forces contribute to cell sheet morphogenesis for dorsal closure in Drosophila. J. Cell Biol. 149: 471-490 (2000).