It's in the fossils and biochemistry, for starters. The evidence for the theory is everywhere. It's also in the comparative morphology of various organism, their embryology, and in biogeographical phenomena such as ring speciesYes, but where's the record that all life came from a common ancestor, as Darwin suggests.
Darwin's central thesis, namely that the relatedness, diversity, complexity, and adaptability of all life on earth arose naturalistically from a single common ancestral microbial population through descent by modification over deep time due to biological variation, trait heritablity, and natural selection - is immovably established, and has been for several decades.
Damaging as it may be to the nation, the dissent of Christians is of no scientific import.