Amniotic egg appears very early in reptilian evolution. Egg has several special extra-embryonic membranes, which allow it to develop on land independent of water. Just as significant as evolution of ...

Eggs, in their simplest form as female reproductive cells, existed long before chickens. The breakthrough came with the evolution of hard-shelled amniotic eggs, which appeared around 325 million ...

Eggs have been around since the evolution of the first amniotes ... A crucial evolutionary step saw the emergence of amniotic eggs. These eggs developed three extra membranes: the chorion ...