From the introduction:
The decision to set this game in the modern setting rather than the more prominent Scopes trial is based on three main factors. First and most important is the fact that the theory of evolution as understood in 1860 or even in 1929 is difficult to defend scientifically today. If students are to learn the science of evolution as part of the process of playing the game, then they should learn reasonably current science. Writings of Stephen J. Gould, Lynn Margulis, and other modern students of evolution will take students beyond Darwin’s simple idea of random mutations into a richer and more complicated understanding of the actual mechanisms of evolution as now understood. These modern scientists, especially Margulis, also answer some of the objections of the Creationists who challenge evolutionary science.