Metamorphosis in amphibians, Biology

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.

Posted Date: 1/30/2013 5:57:50 AM | Location : United States







Related Discussions:- Metamorphosis in amphibians, Assignment Help, Ask Question on Metamorphosis in amphibians, Get Answer, Expert's Help, Metamorphosis in amphibians Discussions

Write discussion on Metamorphosis in amphibians
Your posts are moderated
Related Questions
Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4

Why is water conservation in c3 c4 and cam plants important? Cam stands for Crassulacean acid metabolism. C3 and C4 conserve less water than Cam plants. Actually, C4 plan

PROVIDE a specific example for epithelial and connective tissues, how the arrangement of cells helps with tissue functioning?

Q. What do you mean by Descending Aorta?  The descending aorta begins at the level of the fourth thoracic vertebra. It is defined through the cardiac shadow on the CXR, as it l

Q. How many chromosomes does a human normal diploid cell have? How many chromosomes does a human normal haploid cell have? How many are the sex chromosomes within each of them?

What is Congenital Heart Operations And Interventions Aftercare of the children who have undergone cardiac procedures and surgeries is as important, and in some occasions, more

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

what is the mode of nutrition for worms?

Unified Cell Theory The present unified cell theory states that All living things are composed of either a single Cell or of the cells and cell products. The cell is a m

Q. Causes of reduced Serum HDL levels? Possible causes of reduced Serum HDL levels: - Cigarette smoking - Hypertriglyceridemia - Obesity - Genetic factors - Lack