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

Symbiotic interaction - biological stress, Symbiotic interaction - Biologic...

Symbiotic interaction - Biological Stress Presence of symbiotic microorganism can result in differential growth stimulation of those plants which can recognise the beneficial

Results of pericardial diseases, Results :  Pericardiectomy used to have a...

Results :  Pericardiectomy used to have a mortality of 10-15 per cent in the earlier era. At present it is around 3 to 5 per cent and does not approach 0 per cent even though it

Give some human diseases caused by protozoans, Q. What are other important ...

Q. What are other important human diseases caused by protozoans? Some other significant protozoan infections are amebiasis, trichomoniasis, giardiasis, leishmaniasis, meningoen

Final common pathway of the degradation of organic compounds, Q. Why is the...

Q. Why is the Krebs cycle also called the final common pathway of the degradation of organic compounds? The Krebs cycle is known as the final common pathway of the degradation

What are analogies for mitochondria, Explain What are analogies for mitocho...

Explain What are analogies for mitochondria? Ans) Well, as we know, the mitochondria are the producers of lots of a cell's energy and the nucleolus makes ribosome's.

Explain the regulation of blood glucose concentration, Explain the Regulati...

Explain the Regulation of Blood Glucose Concentration? A number of mechanisms function to maintain blood glucose at remarkably constant level of 70-100 mg/dl under fasting cond

Aetiology, Aetiology:   A List Of The Causes Of A Disease  (Description Of ...

Aetiology:   A List Of The Causes Of A Disease  (Description Of The Characteristic Causes) Factors Which Influence The Onset Of Disease:  Include "Risk Factors", Life-Style, Sex, A

+illustrate sturdy evolutionary hypothesis, Q. Why is it a sturdy evolution...

Q. Why is it a sturdy evolutionary hypothesis that although viruses are the structurally simplest beings they were not the first living beings? The fact that viruses are obliga

Starch, S T ARC H - Polymer of a-D-glucose. Starch is glucosan...

S T ARC H - Polymer of a-D-glucose. Starch is glucosan homopolysaccharide which is the major reserve food of plants. Starch is formed as an end product of photosynt

Explain the failure of implant, Failure of implant The implant is cons...

Failure of implant The implant is considered a failed implant if it presents with even any one of the following features: i) Pain on function (Rule out pain due to soft tis

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