WordNet sense 1 (a process of becoming larger or longer or more numerous or more important):

increase, increment, increase

WordNet sense 2 ((biology) the process of an individual organism growing organically; a purely biological unfolding of events involved in an organism changing gradually from a simple to a more complex level):

development, maturation, ontogeny, growing, ontogenesis

WordNet sense 3 (the gradual beginning or coming forth):

emergence, outgrowth