I'm Carl Simpson, a paleobiologist at the University of Colorado Boulder and the CU Museum of Natural History. I work on the evolution and macroevolution of group living in animals, from multicellularity to colonial marine invertebrates, especially bryozoans and corals. Bryozoans and corals are structured hierarchically, with a mix of important colony- and zooid-level attributes. I am interested in understanding how their evolution is guided by the interactions between selection at the zooid, the colony, and species levels.