I know zip about biology, but I know a little physics. Before Einstein's general theory of relativity challenged it, the prevailing scientific theory of gravitation was Newton's theory. In the minds of most physicists, the issue was resolved in favor of Einstein's theory as a result of an experiment involving an eclipse of the sun. It was the prototypical scientific revolution. Now my two questions: 1. What was the prevailing scientific theory(s) that Darwin's theory of natural selection challenged? 2. What experiment(s) resolved the issue in favor of Darwin's theory in the minds of most biologists?