Metamorphosis in amphibians, Biology

Assignment Help:

Metamorphosis in Amphibians

Metamorphosis is radical in anurans, slight or not exists in urodeles. In anuran amphibians like toads and most frogs, metamorphosis is generally associated with a transition from an aquatic to a terrestrial or amphibious mode of life. Occasionally though no transition in mode of life takes place as observed in the larval and adult of the frog Xenopus laevis and many primitive anurans that remain aquatic throughout their life. The change in habitat in the frogs and toads also generally results in a change in their feeding habit. In some like X laevis there is no change in food habit because both larvae and adult ale carnivorous. Some anurans go through an abbreviated type of metamorphosis before hatching, as they pass through a tailed, gilled tadpole-like stage within the jelly membrane of the egg. Others go through direct development by skipping the larval stages totally.

Metamorphosis in urodele amphibians is generally less striking. Some of them undergo direct development, while others fail to complete their metamorphosis. The latter acquire sexual maturity as larvae, as seen in the axolotl larvae of Ambystoma. This phenomenon is termed as neoteny. Some urodeles like salamanders have been observed to go through two metamorphosis. Metamorphosis in both anurans and urodeles essentially includes the activation of the genomic set underlying the adult organization, which needs for its expression a minimum mass of tissue i.e. greater than that of the egg. The activation is believed to be due to the secretion of a brain hormone that initiates metamorphosis. The hormone triggers the degeneration of redundant larval organs and growth of hitherto quiescent structures that are needed in the adult. In amphibians the process of destruction and growth are smoothly coordinated, as a result of which the animal retains its functional integrity throughout metamorphosis in place of lying dormant as in the case of insects.


Related Discussions:- Metamorphosis in amphibians

Eczema, E c z e m a It is inflammatory reaction of epidermal cells...

E c z e m a It is inflammatory reaction of epidermal cells to the substances to which these cells are sensitized. Such substances may be present either in the external or

Excretory , What are excretory organ and product of a lizard

What are excretory organ and product of a lizard

What is oral rehydration therapy, Q. What is Oral Rehydration Therapy? ...

Q. What is Oral Rehydration Therapy? Oral Rehydration Therapy (ORT) refers to providing fluids and/or oral rehydration salt solutions to the patient. An oral rehydration soluti

What is the difference between anabolism and catabolism, What is the differ...

What is the difference between anabolism and catabolism? Metabolism comprises two opposing processes: anabolism and catabolism. Anabolism is a set of synthesis reactions that t

Assessment of peripheral vascular perfusion (beside test), Assessment of Pe...

Assessment of Peripheral Vascular Perfusion (Beside Test) Burger's Postural Test Perform in daylight.  Place patient supine with both legs elevated and knees

What is the name of process of deposition, Thickness and toughness of plant...

Thickness and toughness of plant walls are increased by deposition within original cellulose wall, of a substance called as lignin. Process of deposition is called: a) Lignific

Why we use histamine in consciousness, Q. Why we use Histamine in conscious...

Q. Why we use Histamine in consciousness? Histamine is involved in controlling the level of consciousness during waking. The level of histamine diminishes during sleep and its

Reproduction, Reproduction Living things do not arise spontaneously. T...

Reproduction Living things do not arise spontaneously. They arise only from pre-existing living things This is one of the fundamental tenets of biology. The ability of an orga

What is the climax stage of an ecological succession, What is the climax st...

What is the climax stage of an ecological succession? The climax stage is the stage of the ecological succession in which the community of an ecosystem becomes stable and does

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd