Comparative embryology is the scientific study of the similarities in structure between the embryos of various species that suggest a possible link to a common ancestor. Early developmental patterns are collated and compared to investigate the likely relationships among evolved organisms.
Scientists have determined that the embryo undergoes a series of evolutionary processes before becoming the present-day form of a species. In spite of the pronounced differences of various organisms in their adult states, comparative embryologists claim that the embryos of these organisms often contain the same structural characteristics as their common ancestor. Through a series of evolutionary stages, these ancestral anatomical structures gradually disappear as the organism develops and matures.