What is Biogenetic law? How comparative embryology does provide evidence for evolution?
It has become evident from embryological studies that there was one developmental pattern. In all organisms, life begins with a unicellular structure. The embryos of fish, frog, turtle, bird, and man resemble one another so closely that it becomes difficult to distinguish them. Mammalian embryo passes through fish–like, amphibian-like, reptiles like and bird-like stages during the development of an organism (ontogeny), some of the evolutionary steps (phylogeny) are repeated in different groups of organisms. This leads Ernst Haeckel to formulate a famous theory – “Recapitulation Theory / Biogenetic Law which states that “Ontogeny recapitulates phylogeny” The sequence of embryonic development shows striking similarity e.g. appearance of gill cleft and notochord in embryonic development of all vertebrates from fish to man.
