
Abstract: One of the primary goals of evolutionary biology is to explain the origin and maintenance of the amazing diversity of species that surrounds us. In this talk, I will discuss perspectives on species maintenance from two systems. First, I will describe how isolation between species evolves through time by comparing patterns across a set of hybrid zones in tropical lizards. I will then share an extension of this work that investigates how isolation evolves across broader phylogenies. Second, I will discuss the role of natural selection in maintaining species boundaries in an adaptive radiation of desert plants. I will conclude by outlining future research directions that aim to generalize the patterns found here.