Embryology studies the development of embryos, from the fertilized egg to the adult organism. By comparing the embryos of different species, scientists have found that they often share similar stages of development, even if the adult animals look very different. This suggests that all animals have evolved from a common ancestor that had a similar embryonic form. For example, the embryos of all vertebrates pass through a stage where they have a tail and resemble fish, even though their adult forms may be quite different. This suggests that all vertebrates evolved from a fish-like ancestor.

2. Embryology can help us to understand how new adaptations evolve.

When comparing the embryos of different species, scientists can trace the developmental changes that led to the evolution of new adaptations. For instance, one evolutionary theory is that whales evolved from land-dwelling ancestors that gradually adapted to life in the water. Evidence for this theory comes from the fact that whale embryos still have structures that are reminiscent of their land-dwelling ancestors, such as hind legs and tailbuds. This suggests that the changes that led to the evolution of whales occurred during embryonic development.

3. Embryology has been used to support the theory of evolution.

Comparative embryology, the study of similarities and differences in the embryos of different species, provided important evidence for Darwin's theory of evolution by common descent. The presence of vestigial structures, recapitulation, developmental homology and embryonic adaptations are embryological evidences in support of evolution.

In summary, embryology provides insights into the processes that drive evolution and has contributed to its fundamental principles, making it valuable in evolutionary studies.