Ralf J. Sommer works in the field of evolutionary developmental biology on nematodes. He has developed and established the nematode Pristionchus pacificus as a model system for integrative studies in evolutionary biology. His research program focuses on the evolutionary analysis of developmental processes and mechanisms and has identified developmental systems drift as general principle for the evolution of development. In the last decade his work focuses on the integration of laboratory studies in nematods genetics and development with field work in ecology and population genetics using the island of La Réunion as a case study. Most recent studies focus on the evolution of novelty and developmental plasticity, revealing how a novel predatory feeding behavior in nematodes is regulated by developmental switch genes and epigenetic regulatory mechanisms.