A four-chambered heart and more efficient lungs allowed greater activity. They have a copulatory organ that permits internal fertilization. Their kidneys are good at conserving water. The produce amniote eggs with covering membranes and a shell, which allow the eggs be laid in dry habitats. The distinctive shell offers protection while conserving water and body heat.
Turtles lay their eggs on land, where predation is high.
Although they resemble lizards, they are evolutionarily more ancient. They do not engage in sex until they are twenty years old. Crocodilians Crocodiles and alligators all live in or near water. Birds Birds apparently evolved from reptiles during the Jurassic.