Our chemical evolution models describe in detail the enrichment process of a number of individual elements from 12C to 56Fe, including delayed SNI contributions. Variation of the characteristic timescale of star formation (SF) t∗ not only results in differences in the abundance evolution but also changes abundance ratios of elements originating from different nucleosvnthetic sites, as e.g. [C/O], [O/Fe], or [Mg/Fe].