Scientific Laws and Theories Quiz The theory of evolution describes how organisms change over time. Scientists now use information in the DNA of living organisms to understand how they are related. The theory of evolution was developed before scientists discovered DNA; however, these new data still fit with and support the theory. What does this sequence of events tell us about the theory of evolution? It is a bad theory because it makes scientists biased. It is a good theory because it is able to explain new evidence. It is a good theory because it has changed greatly over time. It is a bad theory because it was formed before the discovery of DNA.