How did Charles Darwin's theory on evolution change the world?

Before Darwin Biology was a hodge podge of observations and disconnected data. Darwin's theory tied virtually every aspect of biology into a unified field of inquiry. It explains the fossil record, the organization and diversification of species, and virtually every other facet of biology.

Darwin's theory radically changed our view of our position in the universe. Before Darwin it made sense that disease was visited upon unfortunate souls as a divine judgment, or simply "bad luck." After Darwin we realized disease are simply opportunistic organisms randomly taking advantage of natural circumstances.