Glossary

A group of animals that can lay water-tight eggs.  All amniotes are also vertebrates, but only some vertebrates evolved this adaptation to become amniotes.

This adaptation allowed amniotes to live completely on land, out of the water.  Humans, turtles, and birds are all amniotes.  Humans are amniotes even though we don't lay eggs; we have an additional adaptation that allows us to give live birth instead.  Frogs and fish are not amniotes because they must lay their eggs in water.