precursor

This term carries a strong sense of evolutionary progression. It is not merely something that happens first, but something that paves the way or sets the stage for a more advanced or complex version. It implies a direct lineage or a causal link between the early version and the eventual result.

In scientific contexts, such as chemistry or biology, the word describes a specific molecule or substance that is transformed into another. In social or historical contexts, it refers to a pioneering movement or individual whose ideas foreshadowed a later, more successful development.