Metamorphosis (gr. metamorphosis - metamorphosis; synonym indirect development) in biology - poliziadistato development of the animal, characterized by changing its appearance and structure until they reach maturity. Metamorphosis is widely distributed among invertebrates; among vertebrates pronounced in amphibians. Animals, emerging from the metamorphosis, hatch from eggs (ROE) in the form of larvae with bodies that are not included in adults forms, and so on them unlike that can be mistaken for representatives of other species, genus, or even type. In other cases the larvae differ only by their smaller size and the absence or underdevelopment of some organs, characteristic for the adult animals (for example, larvae of insects there are no wings). The larva is transformed into an adult animal or gradually, or metamorphoses it is connected with the passing of stages, sharply different from larvae and adult animals (for example, pupae some insects).
The mechanism M. the most studied of the amphibians. In this case, the stimulating effect of the hormones of thyroid gland. M. insects, apparently, is connected with the activity of the nervous system.