Provides protection from abrasion, as reptile moves over land. During the Carboniferous era, there were many amphibians; the first reptile evolved from labyrinthodont ancestor. Amniotic egg appears ...

leading to the development of the very first chicken. This mutation was replicated in every cell as the chicken embryo grew. Research suggests that amniotic eggs appeared roughly 340 million years ...

The timeless riddle — "Which came first: the chicken or the egg ... The breakthrough came with the evolution of hard-shelled amniotic eggs, which appeared around 325 million years ago ...