The mechanism for the supposed macro-evolution of the fish to the amphibian is purely hypothetical. This lack of transitional forms occurs between all major groups of life. Hypothetical transition forms are drawn to show the change from a reptile to a bird but the fossil record has no evidence that this has ever occurred. Even the closest known intermediate, the Archaeopteryx, was a fully developed bird with the capability of flight like modern birds. Darwin's idea of micro-evolution of the finches can provide no explanation or support for the notion of birds evolving from reptiles.
Evolutionists realize that the fossil record challenges the very notion of macro-evolution.
The extreme rarity of transitional forms in the fossil record persists as the trade secret of paleontology. When looking back through the history of life as recorded in the earth, we find no evidence suggesting the change from one major group to another. We do not have any fossil group which can claim to belong to the ancestor of another major group. Each fossil group has retained its unique and distinct structural and physiological characteristics throughout its life history. The origin of life has long been described by the tree of evolution, with major groups branching off from common ancestors.