The rapid transformation from the larval to the adult form that occurs in the life cycle of lancelets (see cephalochordata) and many invertebrates and amphibians. Examples are the changes from a tadpole to an adult frog and from a pupa to an adult insect. Metamorphosis often involves considerable destruction of larval tissues by lysosomes, and is controlled by hormones, such as ecdysone (in insects) and thyroxine (in amphibians).