Metamorphosis is a process used by various animals to develop from juvenile to adult stage, with larvae often having different physiology and organs. The transformation of a caterpillar into a butterfly is a popular example. Metamorphosis can change an organism’s capabilities, such as tadpoles becoming amphibians and gaining the ability to travel on land. Insects all undergo metamorphosis, with two main types: incomplete and complete. The phenomenon was lost after amphibians, replaced by growth within the uterus.
Metamorphosis is a process used by some arthropods, amphibians, molluscs, cnidarians, echinoderms and tunicates to develop from a juvenile and larval stage to an adult stage. The larva may look like miniature versions of the adult or look completely different, but in most cases they have fundamentally different physiology, including special organs.
One of the most popular conceptions of metamorphosis is the transformation of a caterpillar into a butterfly. This has long been seen culturally as a metaphor for transformation and rebirth, the emergence of a beautiful butterfly from an ugly caterpillar. Before undergoing metamorphosis, the caterpillar wraps itself in a sheath known as a cocoon. Cocoons can have commercial value: cocoons from silkworms, for example, are used to make silk. No accurate reproduction of silk has yet been created in the laboratory.
Metamorphosis can permanently change the capabilities of the organism. For example, tadpoles, the larval form of amphibians, are purely aquatic, but once metamorphosed, they transform into salamanders, newts, frogs, or toads and acquire the ability to travel on land. Toads, a type of frog adapted to keep from drying out, can also spend hours on land with no exposure to water and survive only on moisture burrowing into the earth.
Sometimes the difference between the larval and adult forms is so extreme that the most basic feature, such as the notochord (a kind of primitive backbone) is present in the larval stage but not in the adults, as is the case with tunicates. It is thought that vertebrates may have actually evolved from the larval form of stationary animals such as tunicates. In a manifestation of a phenomenon known as neotony, all vertebrates can be fanciful versions of long-lived tunicate larvae.
Insects all undergo metamorphosis. There are two main types: incomplete metamorphosis and complete metamorphosis. In cases of incomplete metamorphosis, each instar (stage of exoskeleton) changes only slightly from the last, and the organism never enters a sealed cocoon, also known as a pupa. In complete metamorphosis, the entire insect seals itself in a pupa, and changes its body shape considerably. An example would be a worm that turns into a fly. There are many other examples of metamorphosis, in several very large animal phyla. The phenomenon of metamorphosis was apparently lost after amphibians, to be instead replaced by further growth within the uterus.
Protect your devices with Threat Protection by NordVPN
