Various alternative evolutionary mechanisms favoured during "the eclipse of Darwinism" became untenable as more was learned about inheritance and mutation. The full significance of natural selection was at last accepted in the 1930s and 1940s as part of the modern evolutionary synthesis. During that synthesis biologists and statisticians, including R. A. Fisher, Sewall Wright and J.B.S. Haldane, merged Darwinian selection with a statistical understanding of Mendelian genetics.
Modern evolutionary theory continues to develop. Darwin's theory of evolution by natural selection, with its tree-like model of branching common descent, has become the unifying theory of the life sciences. The theory explains the diversity of living organisms and their adaptation to the environment. It makes sense of the geologic record, biogeography, parallels in embryonic development, biological homologies, vestigiality, cladistics, phylogenetics and other fields, with unrivalled explanatory power; it has also become essential to applied sciences such as medicine and agriculture. Despite the scientific consensus, a religion-based political controversy has developed over how evolution is taught in schools, especially in the United States.
Interest in Darwin's writings continues, and scholars have generated an extensive literature, the Darwin Industry, about his life and work. The text of Origin itself has been subject to much analysis including a variorum, detailing the changes made in every edition, first published in 1959, and a concordance, an exhaustive external index published in 1981. Worldwide commemorations of the 150th anniversary of the publication of On the Origin of Species and the bicentenary of Darwin's birth were scheduled for 2009. They celebrated the ideas which "over the last 150 years have revolutionised our understanding of nature and our place within it".