Aquatic and Land Animal Diversity


What are amphibians?

The word “amphibian,” from the Greek amphi (“both”) and bios (“life”), refers to the animal’s double life on land and in water. The usual life cycle of amphibians begins with eggs laid in water, which develop into aquatic larvae with external gills; in a development that shows its evolution, the fishlike larva develops lungs and limbs and becomes an adult—thus, amphibians have made a partial transition to terrestrial life. The living amphibians include newts, salamanders, frogs, and toads. Although lungfish made a partial transition to living out of the water, amphibians were the first to struggle onto land and become adapted to a life of breathing air while not constantly surrounded by water. They were the first vertebrates to have true legs, tongues, ears, and a voicebox—with branches of certain amphibians eventually giving rise to the reptiles.


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