What follows are more conceptual aspects of evolution that build on the ideas discussed in the part 1. It’s not absolutely necessary, but I would recommend checking out part 2 first as well. In this conclusion to my three-part primer on evolution, I will discuss things like reproductive isolation, the different ways that evolution occurs, sexual selection, ecology, chaos theory, and evolutionary equilibrium. That evolution by natural selection has occurred and is occurring is not controversial in biology, which means most biologists are not actively searching for evidence that evolution by natural selection is a true phenomenon – the evidence that it is occurring is in. This post, therefore, introduces you to some of the areas of active research in evolutionary theory.