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

Advantages and disadvantages of mechanical valves, Advantages Durab...

Advantages Durability of these vales are long lasting.  Disadvantages Need for anticoagulant therapy is life long.  Risk of thrombo-embolism is hi

How many asymmetric the amino acid serine have, How many asymmetric carbons...

How many asymmetric carbons does the amino acid serine have? Please explain with a strucutral diagram if possible.

Define sex as a determinants of nutrient requirements, Define Sex as a dete...

Define Sex as a determinants of nutrient requirements? There are some differences in requirements between the two sexes. However, except for iron, these are apparent rather tha

Explain the recommended dietary allowances - nutrition, Explain the Recomme...

Explain the Recommended Dietary Allowances - Nutrition? The recommended dietary allowances are defined as the 'daily dietary intake level that is sufficient to meet the nutrien

What are some functions of the cartilages in the human body, What are some ...

What are some functions of the cartilages in the human body? Cartilages are responsible for the structural support of the nose and ears. The trachea and the bronchi are also or

Vertebrates, i need examples of animals that belongs to vertevrate pisces

i need examples of animals that belongs to vertevrate pisces

Agro industrial-chemical composition and nutritive values, Chemical Composi...

Chemical Composition and Nutritive Values The nutritional quality of an oil meal protein will be affected by the processing conditions to which it is been exposed. Three major

Infants with maple syrup urine disease, Q. Infants with maple syrup urine d...

Q. Infants with maple syrup urine disease? Infants with MSUD appear normal at birth. Once they are fed on protein containing feed, they start showing the classic symptoms. Neur

Define the iodine test - carbohydrates, Define the Iodine Test - Carbohydra...

Define the Iodine Test - Carbohydrates? This test is given by polysaccharides and is not given by monosaccharides or disaccharides. Principle Iodine forms a coloured ad

Synthetic Biology, I need analysis of Stza gene in Aspergillus nidulans thr...

I need analysis of Stza gene in Aspergillus nidulans through synthetic biology, OpenWetWare and Biobricks

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