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 formula of the dpd for withered plant, Q. What is the formula o...

Q. What is the formula of the DPD for withered (shrunken) plant cells and how is that situation possible? Withered plant cells are those that have shrunk due to loss of water b

What is cerebrum, What is Cerebrum Cerebrum is divided into right and l...

What is Cerebrum Cerebrum is divided into right and left parts known as cerebral hemisphere. It is the largest part of the brain. The functions of the cerebrum:  It recei

What are the main prophylactic measures against malaria, Q. What are the ma...

Q. What are the main prophylactic measures against malaria? The major preventive measures against malaria are the elimination of the treatment of infected people, vector mosqui

Explain hypertensive disorders of pregnancy, Explain Hypertensive Disorders...

Explain Hypertensive Disorders of Pregnancy? Hypertension may have been existing before pregnancy. Alternatively, a mother may develop hypertension during pregnancy, a pregnanc

Explain about types of insulin, Q. Explain about types of Insulin? Thre...

Q. Explain about types of Insulin? Three types of Insulin is available. The type varies in how quickly it starts working (lowering blood glucose), time of peak activity (when t

What are the main characteristics of the bryophytes, What are the main char...

What are the main characteristics of the bryophytes? Bryophytes are nonvascular plants, i.e., they do not have conductive tissues and they perform transport of water and nutrie

Conducting system of the heart, The fibrous rings of the four valves of the...

The fibrous rings of the four valves of the heart are continuous with each other. They not only form the basis for the attachment of the corresponding valve cusps but also form an

Altered protein metabolism - metabolic response to injury, Altered Protein ...

Altered Protein Metabolism - Metabolic Response to Injury? Urinary nitrogen loss is extensive following injury, Trauma accelerates nitrogen turnover. In unfed patients, tissue

What is the implant site evaluation, Implant site evaluation 1. Ridge:...

Implant site evaluation 1. Ridge: Total buccolingual width of the ridge- the thickness of the soft tissue ( bucally +lingually)= Buccolingual width of the bone. There shou

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