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Amphibians (greek, “double life”) are a class of animals with vertebrae or backbones. They live part of their lives in water and part on dry land. There are over 3,000 kinds of amphibians known to scientists, most of which have smooth skin without scales. They are the least numerous of all classes of vertebrates. Amphibians first appeared during the Mississippian and Pennsylvanian Periods as land vertebrates. By the Mesozoic Era, the ancestors of present day amphibians appeared probably from the lobe-lunged fish. These ancient fish had lungs and fins with enough muscle and bone to support them on land for a brief period. The prehistoric Labyrinthodontia was one of the first amphibians.

There are three orders of amphibians: legless caecilians (Cymnophiona or Gymnophonia); salamanders, including newts ...

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