Comparative Embryology as a Way to Understand Evolution

Abstract

In the nineteenth century and the first half of the twentieth century, comparative embryology has been indispensable for reconstructing the evolutionary history of Metazoa. The rise of molecular phylogeny and developmental genetics in the last decade of the twentieth century, however, has radically changed the role of comparative embryology in the study of animal evolution. Now, comparative embryology is no longer directly used in building phylogenetic trees, and the role of development in evolution has been recast as the mediator of morphological changes. The new technological developments have enabled investigators to study gene expression patterns and gene functions in embryonic development of many different animal species. By comparing developmental data from different species and reconstructing how developmental mechanisms evolved along the phylogenetic tree, it is now possible to imagine how animal body plans originated and evolved. Therefore, although the role of comparative embryology in evolution research has changed a lot in the past 50 years, it continues to be the forefront of Metazoan evolution research in the twenty-first century.