Evolution is the central organizing principle of the biological sciences. The renowned geneticist Theodosius Dobzhansky wrote, “nothing in biology makes sense except in the light of evolution” (1973). Evolutionary theory has the power to explain biological phenomena over many scales and situations using the same set of relatively simple mechanisms. This course is an introduction to those mechanisms, how they drive evolutionary change in populations, and how they lead to patterns of large-scale diversity among species. The study of evolution is all-inclusive, and draws upon many scientific disciplines including geology, chemistry, physics, mathematics, anthropology, botany, zoology, and computer science in order to develop a comprehensive understanding of the history and diversity of life on Earth.