The evolution of novel forms in multicellular organisms requires alteration of the developmental mechanisms that shaped the earlier form. Evo-devo, short for evolutionary developmental biology, is a relatively young discipline that sets out to retrace how gene and genome modifications have altered existing developmental mechanisms to produce novel forms. Evo-devo has been predominantly applied to the development of animals (19) (20) (21) and, to a lesser degree, of higher plants. (22, 23) However, an understanding of development of other multicellular organisms, such as the social amoebas or fungi will equally benefit from this approach. In the model organism D. discoideum, starving amoebas secrete cAMP pulses, which trigger chemotactic movement and aggregation of cells. Once aggregated, the amoebas differentiate into prestalk and prespore cells in a regulated ratio. The organizing tip continues to emit cAMP pulses, which shape the cell mass by coordinating cell movement. The cAMP pulses also cause the prestalk cells, which are chemotactically most responsive, to move towards the front. At the onset of culmination, the cells synthesize a cellulose tube, the apical prestalk cells move into the tube and mature into stalk cells, the remaining prestalk cells form support structures, such as the upper and lower cup and the basal disk. The prespore cells move up the stalk and mature into spores.