Origin of species continue to fascinate biologists. Even though much of our understanding of speciation rely on empirical research, theoretical research have made significant contributions. One of the (relatively) recent theoretical approach uses bifurcation theory to model speciation. It turns out that disruptive selection, where extreme phenotypes are preferred over common phenotypes, could emerge from frequency-dependent intraspecific competition. And one evolutionarily exciting outcome of this disruptive selection is the origin of new species through an evolutionary branching event. In this talk, I will introduce the theoretical models investigating the emergence of disruptive selection, and build on the existing results in higher dimensional systems.