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

What is the capillarity, What is the capillarity? How this phenomenon chemi...

What is the capillarity? How this phenomenon chemically explained? What is relevance of the capillarity for water transport in plants? The Capillarity is the phenomenon through

Evolutionary evidence, describe the discovery of new fossil evidence for ev...

describe the discovery of new fossil evidence for evolution

Zoloogy, two main evolutionary novelties presented by annelids

two main evolutionary novelties presented by annelids

Parts of a seed , Parts of a Seed Seed is attached to the fruit by a ...

Parts of a Seed Seed is attached to the fruit by a stalk, the funiculus (funicle). The prolongation of the funiculus running along the seed and terminating at the chalaza is

Byproducts of low digestibility high in nitrogen, Byproducts of the food i...

Byproducts of the food industry, such as coffee residues, fruit pulp and cocoa meal are of low energy value, but are relatively high in nitrogen. In additional, animal excreta tend

Describe the complete transposition of great arteries, Describe the Complet...

Describe the Complete transposition of great arteries ? Lethal, relatively frequent malformation. Without treatment, it results in 30 per cent mortality within the first week o

Cerebral palsy, Cerebral Palsy Cerebral palsy is a non-progressive neu...

Cerebral Palsy Cerebral palsy is a non-progressive neuromuscular disorder characterised by disorder of strength, muscle control, posture or movement due to brain injury, befor

What is the mendels first law, What is the Mendel's first law? The Mend...

What is the Mendel's first law? The Mendel's first law postulates that a characteristic (trait) of an individual is always verified by two factors, one inherited from the fathe

Electrodialysis, This method is used for the desalination of water i.e., fo...

This method is used for the desalination of water i.e., for the removal of dissolved mineral salts, acids, alkalis and also the radioactive substances from the effluents. Electro d

Measuring ecosystem diversity, Measuring ecosystem diversity is not easy, a...

Measuring ecosystem diversity is not easy, and ther e is no definite index for its measurement. It is generally assessed by the measure of species diversity in an ecosystem, often

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