The tuatara has survived without significant change for 200 million years on some small islands off the coast of New Zealand. There are, however, a number of physical differences between reptiles and amphibians. Newborn reptiles are miniatures of the adult whereas most amphibians develop through a larval stage before reaching their adult body form. During this larval stage, amphibians are completely dependent upon water, living much like fish and even breathing through gills. Reptiles are not as dependent on water and some rarely even drink water directly.
Amphibian skin lacks hair or scales.
If the skin dries out they cannot do either and will die. The nature of their skin makes amphibians very susceptible to dehydration. Despite this, amphibians are found in desert regions. In fact, amphibians can live almost anywhere with one major exception. They are found on every continent except Antarctica.