Evolutionary biology is the subfield of biology that studies the evolutionary processes that produced the diversity of life on Earth, starting from a single common ancestor. These processes include natural selection, common descent, and speciation. The discipline emerged through what Julian Huxley called the modern synthesis (of the 1930s) of understanding from several previously unrelated fields of biological research, including genetics, ecology, systematics, and paleontology. Current research has widened to cover the genetic architecture of adaptation, molecular evolution, and the different forces that contribute to evolution including sexual selection, genetic drift and biogeography. The newer field of evolutionary developmental biology ("evo-devo") investigates how embryonic development is controlled, thus creating a wider synthesis that integrates developmental biology with the fields covered by the earlier evolutionary synthesis.