In reference to evolution, homology can be described as the comparative similarities in the structures of organisms that make it more alike to one organism than the other organisms. It also shows the characteristics that might have evolved in an organism over time. Developmental homology are the similarities which arise between organisms due to similar embryological source.
Developmental studies can be made by researching the embryological developments of different organisms and looking for similarities among them.
For example, studying the snake embryos showed that some of the embryos have hind limb buds in them which disappeared in the mature snake. This study made it clear that snakes evolved from organisms that had hind limbs. As the snakes do not need the limbs, so with time the species of snakes evolved and lost their hind limbs.
