Morphogenesis refers to the set of complex movements and deformations that tissues experience during development to give rise to the three dimensional form of organs and organisms. From a biomechanical perspective tissues represent a unique class of materials, which exhibit dynamic mechanical properties that evolve over time. Little is known about how these macroscopic properties arise from the interplay and integration of molecular, cellular and tissue events. In this project, I propose to use the process of Dorsal Closure of the Drosophila embryo to undertake a dynamic study of morphogenesis spanning the molecular, cellular and tissue levels, to obtain insights into how tissue properties emerge from the coordinated activity of its constituent cells. These studies will focus on the amnioserosa, one of the main force-generating tissues during DC that has proved to be a powerful system to study the emergence of morphogenetic forces. The focus of this project is to understand the molecular mechanisms underlying actomyosin activity, how they translate into effective cell shape changes and how this activity is coordinated across the whole tissue to give rise to the contractile activity of the tissue. For this, I will use a combination of classical genetics and state of the art microscope techniques to obtain quantitative information on the dynamic behaviour of molecules, sub-cellular modules and cells. I will investigate how molecular and cellular events impinge on the mechanical properties of the tissue, which will be probed by laser ablation experiments in wild type and in embryos with perturbed actomyosin dynamics. The multi-disciplinary research outlined in this project has the potential to make significant contributions to the young field of cell-developmental biology and the physical and engineering sciences.