Why did some Darwinian scientists initially oppose Mendelian inheritance?

Initially, many Darwinian scientists opposed Mendelian inheritance because of a fundamental disagreement regarding the nature of variation.1

Darwinian evolution was widely assumed to rely on the selection of small, blending variations. In contrast, Gregor Mendel’s work focused on distinct, nonblending variations that were transmitted as separate, particulate units. Because Mendel’s findings appeared to contradict the prevailing model of continuous, blending inheritance, early proponents of his theory—known as Mendelians—faced significant opposition, and their work was often dismissed as irrelevant to the study of evolution.12

It took approximately three decades for the scientific community to reconcile these views and for Mendelian theory to be integrated into the broader framework of evolutionary biology.1