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

Skeletal system - cerebro-spinal fluid, Cerebro-spinal Fluid - Formed m...

Cerebro-spinal Fluid - Formed mainly by choroid plexus and ependyma of ventricles. It comes out of medulla oblongeta by foramen of magandie and lushka . Slightly alkalin

Explain about adhesive tape of many varieties, Explain about Adhesive tape ...

Explain about Adhesive tape of many varieties Adhesive tape of many varieties with backing materials coated with an adhesive to keep the dressing in place. The adhesive bandage

Differentiate blood retinal barrier and aqueous barrier, What are the diffe...

What are the differences between blood retinal barrier and blood aqueous barrier? Blood Retinal Barrier: Blood retinal barrier is present in retina. In retina there are t

Gastrulation, Gastrulation The end of cleavage of the unicellular zyg...

Gastrulation The end of cleavage of the unicellular zygote results in the creation of multicellular blastula, which may be a solid structure with no a cavity (stereoblastula)

Explain nature of fatty acids present in the triglyceride, Explain the Natu...

Explain the Nature of fatty acids present in the triglyceride? Nature of fatty acids present in the triglyceride determines the physico-chemical properties and biological signi

Can you explain myopia and hypermetropia, Q. How can the visual deficiencie...

Q. How can the visual deficiencies known as myopia and hypermetropia be optically explained? Myopia is the visual condition in which the images are formed previous to (in front

What are the cell movements, Q. What are the cell movements and how are the...

Q. What are the cell movements and how are these movements created? Cell movements are movements executed by cell structures, like the movements of flagella and cilia, the pseu

Define the petrifilm (dry film) method, Define the Petrifilm (dry film) Met...

Define the Petrifilm (dry film) Method? An alternative method to the conventional SPC is a Petrifilm (dry film) method. It is a non-petri dish plating system where a layer of n

What is rflp, Question 1 Write a short note on the following              ...

Question 1 Write a short note on the following                    1 Microinjection                    2 Bio catalysis Question 2 What is RFLP? With help of schematic diagr

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