Darwin is deservedly given credit for the theory of biological evolution. Most important, however, is that he discovered natural selection, the process that accounts for the adaptive organization of organisms and their features; that is, their "design." UC Irvine professor Francisco J. Ayala, explains that the design of organisms is not intelligent, as would be expected from an engineer, but imperfect and worse. Natural selection is Darwin's gift to religion, because the dysfunctions and waste of the living world need not be attributed to the Creator, but explained as an outcome of a natural process. (#21385)