Sexual Selection, Species Recognition, and Speciation Reinforcement is the process by which two partially reproductively isolated species come into secondary contact with one another, and further reproductive isolating mechanisms are evolved to reduce or prevent hybridization between the two. Presumably, reinforcement evolves from the selection pressures to reduce hybridization. By definition, reinforcement cannot initiate the process of speciation to generate reproductive isolation, but it must act through selection on the same types of processes as at the initial stages of speciation. In this question, we would like for you to develop a narrative about the process of reinforcement and the issues raised by it along the following lines. First, briefly review the concept of reinforcement and the empirical evidence for the operation of the process. The classic model typically considers a system consisting of two parts: mate preference and a mating trait. The genetic architecture of these two components can shape the evolution of reinforcement and nonrandom mating in general. Expound on the genetic conditions for these two components can hasten or retard their evolution? Then break out of the classic model and evaluate various types of premating and postmating isolating mechanisms as effective evolutionary pathways to reducing the level of hybridization. In particular, many people focus on the further evolution of genetic incompatibilities as the outcome of reinforcement. However, pre- mating barriers to gene flow would seem to also work as well. In particular, focus on the relative advantages and disadvantages of each as the outcome of reinforcement, and highlight some real world examples of each type of isolating mechanism you discuss. Finally, consider the consequences of each of these types of mating barriers that may evolve via reinforcement to the intraspecific mating advantages of a species. Namely, how might the evolution of isolating mechanisms via reinforcement influence mating dynamics with conspecific partners – both for males and females.