Since they lack an amniotic egg, they must lay their eggs in water and undergo metamorphosis.
This class of animals most likely evolved from the Rhipidistians, and other ancestors of this class include Acanthostega and Tiktaalik, which was recently discovered in the Arctic. This class, which possesses a unique three-chambered heart, includes the caecilians, who are worm-like, and they were the first tetrapods to evolve. Since they lack an amniotic egg, they must lay their eggs in water and undergo metamorphosis. For 10 points, name this animal class that can live on land and in water, which includes frogs.
This class of animals most likely evolved from the Rhipidistians, and other ancestors of this class include Acanthostega and Tiktaalik, which was recently discovered in the Arctic.
Amphibians