The developmental mechanisms transforming genotypic to
phenotypic forms are typically omitted in formulations of genetic
algorithms (GAs) in which these two representational spaces are
identical.  We argue that a careful analysis of developmental
mechanisms is useful when understanding the success of several
standard GA techniques, and can clarify the relationships between more
recently proposed enhancements.  We provide a framework that
distinguishes between two developmental mechanisms --- learning and
maturation --- while also showing several common effects on GA search.
This framework is used to analyze how maturation and local search can
change the dynamics of the GA.  We observe that in some contexts,
maturation and local search can be incorporated into the fitness
evaluation, but illustrate reasons for considering them seperately.
Further, we identify contexts in which maturation and local search can
be distinguished from the fitness evaluation.