metamorphosis (mĕt'əmôr`fəsĭs) [Gr.,=transformation], in zoology, term used to describe a form of development from egg to adult in which there is a series of distinct stages. Many insects insect, invertebrate animal of the class Insecta of the phylum Arthropoda . Like other arthropods, an insect has a hard outer covering, or exoskeleton, a segmented body, and jointed legs. Adult insects typically have wings and are the only flying invertebrates.
..... Click the link for more information. , amphibians, mollusks, crustaceans, and fishes undergo metamorphosis, which may involve a change in habitat, e.g., from water to land. Metamorphosis is called complete when there is no suggestion of the adult form in the larval stage, e.g., in the transformation from tadpole tadpole, larval, aquatic stage of any of the amphibian animals. After hatching from the egg, the tadpole, sometimes called a polliwog, is gill-breathing and legless and propels itself by means of a tail.
..... Click the link for more information. to frog frog, common name for an amphibian of the order Anura. Frogs are found all over the world, except in Antarctica. They require moisture and usually live in quiet freshwater or in the woods.
..... Click the link for more information. or from larva larva, independent, immature animal that undergoes a profound change, or metamorphosis, to assume the typical adult form. Larvae occur in almost all of the animal phyla; because most are tiny or microscopic, they are rarely seen.
..... Click the link for more information. to pupa pupa (py
..... Click the link for more information. to adult in bees and butterflies. When the successive larval stages resemble the adult (as in the grasshopper and the lobster), metamorphosis is called incomplete.

metamorphosis

In biology, any striking developmental change of an animal's form or structure, accompanied by physiological, biochemical, and behavioral changes. The best-known examples occur among insects, which may exhibit complete or incomplete metamorphosis (see nymph). The complete metamorphosis of butterflies, moths, and some other insects involves four stages: egg, larva (caterpillar), pupa (chrysalis or cocoon), and adult. The change from tadpole to frog is an example of metamorphosis among amphibians; some echinoderms, crustaceans, mollusks, and tunicates also undergo metamorphosis.

metamorphosis

Zoology the rapid transformation of a larva into an adult that occurs in certain animals, for example the stage between tadpole and frog or between chrysalis and butterfly

metamorphosis [‚med·ə′mȯr·fə·səs]

(biology)

A structural transformation.

A marked structural change in an animal during postembryonic development.

(medicine)

A degenerative change in tissue or organ structure.

Metamorphosis

A pronounced change in both the internal and external morphology of an animal that takes place in a short amount of time, triggered by some combination of external and internal cues. The extent of morphological change varies considerably among species. Even when morphological changes are relatively slight, metamorphosis typically brings about a pronounced shift in habitat and lifestyle. The precise morphological, physiological, and biochemical changes that constitute metamorphosis; the neural, hormonal, and genetic mechanisms through which those changes are controlled; and the ecological consequences of those changes and when they take place continue to be studied in a wide variety of animals. The hormonal and genetic control of metamorphosis has been best examined in a few species of insect, amphibian, and fish (such as flounder), but other aspects of metamorphosis have been investigated for other insect, amphibian, and fish species as well as for marine invertebrates and, indeed, representatives of essentially every animal phylum.

Amphibians exhibit extensive tissue remodeling during metamorphosis, including resorption of the tail musculature and skeletal system; major reconstruction of the digestive tract; degeneration of larval skin and pronounced alteration in skin chemical composition; growth of the hind and fore limbs; degeneration of the gills and associated support structures; shifts in mode of nitrogen excretion, from ammonia to urea; alteration in visual system biochemistry; replacement of larval hemoglobin with adult hemoglobin; and differential growth of the cerebellum. See Amphibia

Metamorphosis among insects is associated primarily with wing development. Bristletails and other species that do not develop wings and are not descended from winged ancestors exhibit no pronounced metamorphosis. Metamorphosis is most dramatic among holometabolous species, which pass through a distinctive and largely inactive pupal stage; in such species, all of the transformations separating the larval morphology and physiology from that of the adult take place in the pupa. Wings, compound eyes, external reproductive parts, and thoracic walking legs develop from discrete infolded pockets of tissue (imaginal discs) that form during larval development. See Insecta

The most dramatic metamorphic changes in fish are seen among flounder and other flatfish: in such species, during metamorphosis a symmetrical fish larva becomes an asymmetrical adult, with both eyes displaced to the dorsal surface. The transformation of leptocephalus larvae into juvenile eels is also dramatic; such transformation includes a shift in the position of the urinary and digestive tracts from posterior to anterior.

The control of metamorphosis among crabs, barnacles, gastropods, bivalves, bryozoans, echinoderms, sea squirts, and other marine invertebrates is poorly understood, partly due to the very small size of the larvae—they rarely exceed 1 mm in length, and most are less than 0.5 mm. The larvae of some marine invertebrate species are triggered to metamorphose by specific substances associated with adults of the same species, or with the algae or animals on which they prey. See Annelida, Bivalvia, Echinodermata, Gastropoda, Mollusca

Among insects, the timing of metamorphosis is influenced by environmental factors such as temperature, humidity, photoperiod, pheromone production by neighboring individuals, and the nutritional quality of the diet. In a number of species, larvae can undergo developmental arrest (a diapause) in response to unfavorable environmental conditions, so that metamorphosis can be delayed for many months or even years. The hormonal basis for such effects has been at least partly worked out for a number of insect species.

Among marine invertebrates and in at least some fish species, there is also considerable flexibility in the timing of metamorphosis. At some point in the development of marine invertebrates and apparently also in the development of some coral reef fishes, individual larvae become “competent” to metamorphose. It is not yet clear what makes larvae competent; the development of external receptor cells, or the completion of specific neural pathways, or the activation of hormonal systems or their receptors are likely possibilities. See Endocrine system (invertebrate)

Metamorphosis

Gregor Samsa turned into a huge insect. [Ger. Lit.: Kafka Metamorphosis]

See : Insect

metamorphosis (redirected from METAMORPHOSE - METAMORPHOSIS Mask Sound & Dance Theatre)

metamorphosis

metamorphosis
(redirected from METAMORPHOSE - METAMORPHOSIS Mask Sound & Dance Theatre)