Metamorphosis: amphibians go through a metamorphosis from a tadpole or larval stage with gills to an air-breathing adult stage. Reptiles do not go through metamorphosis. When the young are born or hatched, they look like miniature adults.
That is correct. The process of metamorphosis is particularly striking in amphibians such as frogs and salamanders. They typically start their life cycle in water as larvae, like tadpoles in the case of frogs, where they breathe through gills and have a tail for swimming. As they go through metamorphosis, they develop lungs for breathing air, legs for hopping or walking (in the case of frogs), and lose their tails (in the case of frog tadpoles). This transformation allows them to live on land as adults, although many amphibians still require moist environments or have a close association with water.
Reptiles, on the other hand, do not undergo metamorphosis. When reptiles such as snakes, lizards, turtles, and crocodilians hatch from eggs or are born, they resemble smaller versions of their adult form and they do not undergo significant morphological changes as they grow. They are fully formed to function in their environment from the start, with lungs to breathe air and the ability to move on land or in water, depending on the species.
This difference between amphibians and reptiles is one of the key characteristics that distinguish these two classes of animals within the phylum Chordata, subphylum Vertebrata.