The first amniotes, such as "Casineria", looked like small lizards. They evolved about 340 million years ago, in the Mississippian or Lower Carboniferous. Their eggs could survive out of the water. This let amniotes move into environments that had less water. The amniotes moved across the Earth. Most vertebrates that live on land are amniotes, as are most of the air-breathing animals of the sea.