Hormones in metamorphosis of amphibia, Biology

Hormones in Metamorphosis of Amphibia

In amphibians, the changes that take place during metamorphosis are brought about by hormonal secretions of the thyroid gland. The first sign of this was obtained in 1912 when Gudematsch reported that frog tadpoles while fed dried and powdered sheep thyroid underwent precocious or early metamorphosis. Identical results however were not observed when tadpoles were fed along with preparation of other glands. These experiments made it feasible to postulate that thyroid hormones bring about metamorphosis.

In 1918 B.M. Allen observed that elimination of thyroid rudiment from early frog tadpoles, prevented them from going through metamorphosis, and caused them to become giant tadpoles instead. Conversely, if they were fed with thyroid or immersed in water containing soluble extracts from thyroid glands they then proceeded immediately to metamorphosis. Identical experiments in urodele amphibians, in particular in axolotl, Ambystoma mexicanum, also indicated the significance of the thyroid gland in urodele metamorphosis.

Posted Date: 1/30/2013 6:17:45 AM | Location : United States







Related Discussions:- Hormones in metamorphosis of amphibia, Assignment Help, Ask Question on Hormones in metamorphosis of amphibia, Get Answer, Expert's Help, Hormones in metamorphosis of amphibia Discussions

Write discussion on Hormones in metamorphosis of amphibia
Your posts are moderated
Related Questions
How might the destruction of large areas of tropical rain forest have world-wide consequences? As plants consume CO 2 during photosynthesis, extensive deforestation could resu

Explain how a water molecule is produced when glucose and fructose undergo a condensation reaction. The glucose molecule releases a hydroxide ion, OH -, and the fructose molec

Hereditary fructose interolance is a rare recessive disorder that is caused by a mutation in the aldolase B gene. As a result of this disorder individuals may have all of the follo

Explain the Explosion Puffing? Explosion puffing has been recognized as one of the most significant developments in dehydration technology. In explosion puffing, partially dehy

Question 1 What is fixative? Discuss the characteristics of a good fixative. What is the importance of using a good fixative for tissue processing? Question 2 What is embe

Minerals :- Magnesium    Food Source      Whole grains, nuts, legumes, green leafy vegetables Nutritional Functional role Essential nutrient: Deficiency is rare Co

Complete feed blocks For manufacturing the pellets, processes such as grinding, mixing, steaming and pressing and some times extruding, are applied using special and expensive

Q. What is an example of a lab experiment that shows the variation of the photosynthesis effectiveness in relation to different photic energy frequencies to which the reaction is e

WHY CONSERVE WILD LIFE ? 1 .       ECONOMIC IMPORTANCE OF WILD LIFE - (i) Plants - (ii) Animals - (iii) Micro organisms - 2 .       ECOLOGICAL BALANCE -

Economic Significance - Conservation of Wildlife Certain wild species are important because of their actual or potential economic value to people. Wildlife resources provide p