evolution

英[,iːvə'luːʃ(ə)n;'ev-] 美[,ivə'luʃən]

1. a process in which something passes by degrees to a different stage (especially a more advanced or mature stage);: "the development of his ideas took many years"; "the evolution of Greek civilization"; "the slow development of her skill as a writer"

2. (biology) the sequence of events involved in the evolutionary development of a species or taxonomic group of organisms