“The embryo of a higher form never resembles any other form, but only its embryo”. This is one of the laws of embryology proposed by

Von Bear’s Principles of Embryonic Differentiation:

1. The more general characters of a large group appear earlier in the embryo than the more special characters.
2. From the more general, the less general and finally the specialised characters appear.
3. An animal during development departs progressively from the form of other animals.
4. Young stages of an animal do not resemble the adult of any other form, but they resemble its embryo.

Ernst Haeckel proposed Biogenetic Law which states that “ontogeny repeats phylogeny”.