The use of modules in morphogenesis allows both single changes affect multiple instances, and for the number of instances to be easily changed. E.g., a change to the shape of a finger changes all of the fingers at once. And a change to the number of repetitions increases or decreases the number of fingers with ease. [[Cell specialization into distinct cell types requires modularity]] [[Clune 2013]] - selecting for fewer connections improves "modularity" of the resulting network