The study of the embryonic development of living organisms provides indisputable evidence of evolution.
Embryological evidence is:
- the development of all sexually reproducing organisms from one cell – a zygote;
- the similarity of the early stages of development of the embryos of different groups of animals at the early stages of embryonic formation (Baire’s law);
- the Muller-Haeckel law that an individual repeats the history of the emergence of its species in embryogenesis.
It is known that every multicellular organism begins its development from one cell – a zygote.
In the early stages of development, the embryos of organisms of the same type are similar. For example, in the embryos of all vertebrates, the notochord, neural tube and gills are first formed.
As it develops, the distinctive features become more and more noticeable.
In the first half of the 19th century. Russian embryologist K.M.Bair formulated the law of embryonic similarity.
The earlier stages of individual development are compared, the more similarities can be found between different organisms.
This pattern in the development of embryos indicates the relationship and sequence of evolutionary divergence of groups of organisms.
In the second half of the 19th century. German scientists E. Haeckel and F. Müller formulated the biogenetic law.
Each individual in individual development repeats the history of the development of the species (ontogeny is a short and rapid repetition of phylogeny).
Later it was found that in ontogeny, the characters are repeated not of adult ancestors, but of their embryos.
Based on the biogenetic law and using the data of embryology, it is possible to recreate the course of the historical development of certain groups of organisms. This is especially important in cases where the fossil remains of ancestral forms are unknown.