The alleged evolution of reptiles from amphibians is difficult for the theory of evolution to explain. The first has to do with skin. An amphibian's skin lacks protective devices to stop it from drying out. This forces it to live in water or very humid places. Some amphibians have a type of thin scale in their skin, but this offers no protection against drying out.
Reptiles have a different type of scale altogether, made of keratin, or horn.
It lies in the outer layer of their skin and is tough enough to prevent desiccation. There is no convincing evidence from either biology or fossils that such a transformation took place. The second major barrier to an amphibian's turning into a reptile has to do with eggs. An amphibian, hatching from an aquatic egg, develops in water in the larval form known as a tadpole. Reptiles, however, are born with all the functioning structures of an adult.