It is the study of the anatomy, physiology, biochemistry, behavior, and evolution of amphibians and reptiles. In general, amphibians begin life as gilled aquatic larvae. They their bodies undergo several metamorphosis and eventually become air-breathing adults. Their body temperature is slightly higher than the environment. They are active at optimal temperatures and withdraw from more extreme heat or cold.
Most amphibians have four limbs.
The scales and amniote egg evolved by reptiles. There are considered to be three orders of amphibians or Amphibia which have been placed in the subclass Lissamphibia. The super order Salientia includes extinct frog-like forms, and the extant order Anura consists of the frogs and toads. The order Caudata includes the salamanders. The order Gymnophiona includes the limbless caecilians.