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

Vaccines, Ask quesWhat type of antigenic agents may constitute vaccines? ti...

Ask quesWhat type of antigenic agents may constitute vaccines? tion #Minimum 100 words accepted#

Define obligatory nitrogen losses, Define Obligatory Nitrogen losses? T...

Define Obligatory Nitrogen losses? The Committee estimated the total obligatory nitrogen losses through faeces, urine, skin and other miscellaneous routes in adult men as 2.0 m

Integumentary, What modern technology used for the integumentary system?

What modern technology used for the integumentary system?

Diagnosis and treatment of rheumatic fever, Diagnosis  History and ...

Diagnosis  History and Physical examination.   John's criteria.   Echocardiogram show valvular insufficiency.   Chest X-ray cardiomegaly if CHF present.   EC

State tantalum and niobium in alloplastic implant material, Tantalum and Ni...

Tantalum and Niobium in alloplastic implant materials  Tantalum has been used successfully in needle type, screw- type and double-bladed implants. However, both are difficult

Metabolism of fructose, Fructose is an abundant sugar in the human diet; su...

Fructose is an abundant sugar in the human diet; sucrose (table sugar) is a disaccharide that when hydrolyzed yields glucose and fructose and fructose is also a major sugar in hone

What is a species, What is a species? A species is a set of living bei...

What is a species? A species is a set of living beings able to cross between themselves generating fertile offspring. This method though does not apply to individuals of ex

Define the sun and solar drying method, Define the Sun and Solar Drying Met...

Define the Sun and Solar Drying Method? The make use of solar energy to preserve the food items is mainly the oldest form of food reservation and is still practiced today for f

Fission - asexual reproduction, Normal 0 false false false ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Explain the term ferns, Explain the term Ferns? Ferns are plants that...

Explain the term Ferns? Ferns are plants that have vessels that conduct water, minerals, and nutrients, and reproduce through spores, rather than seeds. Ferns are therefore o

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