how does an amphibian change as a result of metamorphosis?

Answer 1

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.

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, 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 to frog or from larva to pupa to adult in bees and butterflies. When the successive larval stages resemble the adult (as in the grasshopper and the lobster), metamorphosis is called incompleteMetamorphosis is a process in biology by which an individual physically develops after birth or hatching, and involves significant change in form as well as growth and differentiation. It usually accompanies a change of habitat or of habits, but may occur without such change. It was once thought that, in those cases where the animal's habitat remains unchanged, metamorphosis followed a series of forms representing evolutionary ancestors of the species in question (see ontogeny recapitulates phylogeny), but this is no longer thought to be true.

The first type of metamorphosis is illustrated by many insects and by amphibians. Immature dragonflies are aquatic, though the adults are flying insects, and frogs undergo a metamorphosis from an aquatic tadpole to an amphibious adult form. Change of habits is illustrated by the transformation of the free-swimming young of many aquatic invertebrates into sessile adults (eg sea squirts), and the development of butterflies and moths from caterpillars with chewing mouthparts into flying insects with sucking mouthparts.

The second type is illustrated by many crustacean species, whose young undergo significant physical metamorphosis without changing habits or habitat significantly.

The immature stages of a species that undergoes metamorphosis are designated by the term larva. In the complex metamorphosis of many insect species, however, only the first stage is called a larva and sometimes even that bears a different name; the distinction depends upon the nature of the metamorphosis.

Some insects hatch from the egg, already having the general form of the adult, and the metamorphosis to adult form is usually marked mainly by the development of wings. This type of metamorphosis is called simple, gradual, or incomplete metamorphosis (hemimetabolism), and the young are called nymphs, or naiads when aquatic. It is often found in the order Mantodea or genus Stagomantis, which is commonly known as the praying mantis. They do not undergo stages like a caterpillar to a butterfly. Instead, they undergo several stages where the nymph of, e.g., a praying mantis looks like a smaller-sized, wingless adult and ends the metamorphosis with fully developed wings.

Insects with complete metamorphosis pass through a larval stage and then enter an inactive state known as a pupa (or chrysalis), finally emerging as the adult form. A number of beetle species and Strepsiptera undergo hypermetamorphosis, with a sequence of different larval forms preceding pupation.

Whether the insect spends more time in its adult stage or in its juvenile form depends on the individual species; notable examples of the latter are the mayfly, whose non-eating adult stage lives as little as a single day, and the cicada, whose juvenile stage lives underground for as much as seventeen years. However, these species have incomplete metamorphosis; typically (though not exclusively), species in which the adult form outlives the juvenile form undergo complex metamorphosis.

Many observations have indicated that cell death plays a considerable role during physiological processes of multicellular organisms, particularly during embryogenesis and metamorphosis.

Comparative Lengths of Metamorphosis Species Egg Larva/Nymph Pupa Adult
Housefly 1 day 2 weeks 1 week 2 weeks
Ladybug 4 days 2 weeks 2 weeks 3-9 months
Monarch Butterfly 4 days 2 weeks 10 days 2-6 weeks
Periodical Cicada 1 month 13/17 years no such stage 2 months
Mayfly 1 month 3 years 1 day
Cockroach 1 month 3 months 9 months

Insect metamorphosis
All Apterygota and most Exopterygota insects are Hemimetabolic, while all Endopterygota are Holometabolic.

It must be noted, however, that a few Exopterygota - e.g. Thysanoptera, Aleyrodidae and male Coccoidea - are subject to a metamorphosis more similar to the Hemimetabolic one.

Hormonal control of metamorphosis in insects
Insect growth and metamorphosis are controlled by hormones syntesized by endocrine glands near the front of the body. Some cells of insect brain secrete a hormone that activates thoracic glands.

Once they are activated, these glands secrete a second hormone, usually Ecdysone (a steroid), that induces metamorphosis.

Moreover, the corpora allata produce the juvenile hormone, whose effect is to prevent the development of adult characteristics while allowing ecdysis.

Therefore, the insect is subject to a series of moult, controlled by Ecdysone, until the production of juvenile hormone ceases and metamorphosis occurs.

Answer 2

it changes from a tadpole into a frog.
loses its tail..