Sean Carroll in Preposterous Universe:
Evolution is a messy business, involving as it does selection pressures, mutations, genetic drift, and the effects of random external interventions. So in the end, how much of it is predictable, and how much is in the hands of chance? Today we’re thrilled to have as a guest my evil (but more respectable, by most measures) twin, the biologist Sean B. Carroll. Sean is both a leader of the modern evo-devo revolution, and a wonderful and diverse writer. We talk about the importance of randomness and unpredictability in life, from the evolution of species to the daily routine of every individual.
More here.