Amphibians, not quite fish and not quite reptiles, were the first vertebrates to live on land. These cold-blooded animals spend their larval stage in water, breathing through their gills. In adulthood they usually live on land, using their lungs to breath air. This double life is also at the root of their name, amphibian, which, like many scientific words, derives from Greek. The Greek prefix amphi- means both, or double, and the Greek word bios means life. Both these elements are widely used in English scientific terminology: bios, for example, is seen in such words as biology, antibiotic, and symbiotic.

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