During their embryology, higher organisms pass through forms that are similar to forms seen in the embryos of their evolutionary ancestors. During their embryology, higher organisms pass through stages equivalent to the adult forms of their evolutionary ancestors.
Embryos develop from general to specific.
Early in development, embryos have many features in common. As they develop, they diverge and become ever less like each other and ever more like a particular species. During ontogeny, evolutionarily old structures found in old species often appear in more modern species but are often used to form new structures in the more modern species. Some new structures are formed in more modern species that have no appearance in any form in earlier species. All rights reserved.