Reticulate Evolution

Reticulate evolution refers to evolutionary processes that merge lineages rather than splitting them, producing network-like rather than tree-like patterns of descent. Hybridization between species, horizontal gene transfer, and endosymbiosis are all forms of reticulate evolution. In plants, hybridization is so common that the concept of discrete species boundaries often breaks down. Reticulate evolution challenges classical phylogenetic methods built on bifurcation, and has driven the development of network-based phylogenetics. It suggests that at certain scales, evolution is better understood as a process of combination and fusion than of divergence and radiation — a perspective that connects biology to complex adaptive systems and the study of network topology.