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Amphibian Reproduction - Anatomy & Physiology (view source)
Revision as of 12:29, 23 July 2008
, 12:29, 23 July 2008→Maternal
* Epidermal clutch carrying.
* Epidermal clutch carrying.
** Eggs are carris in small pores in the skin and hatch by bursting through them.
** Eggs are carris in small pores in the skin and hatch by bursting through them.
** The female swallows the clutch, covering them with a secretion to protect against the acidic environment of the stomach.
=== Gastric brooding ===
** When the clutch is fully developed, the mother will regurgitate them to the exterior.
* Deposit the clutch and return to them with food.
The Gastric-brooding frogs or Platypus frogs were a genus of ground-dwelling frogs native to Queensland in eastern Australia. The genus consisted of only two species, both of which became extinct in the mid-1980s. The genus was unique because it contained the only two known frog species that incubated the prejuvenile stages of their offspring in the stomach of the mother.
* Female ingests the fertilized eggs.
* In the jelly that surrounds each egg is a substance called prostaglandin E2 (PGE2).
* This substance has the ability to turn off the production of hydrochloric acid in the stomach. This source of PGE2 is enough to cease the production of acid during the embryonic stages of the developing eggs.
** Once the eggs hatch, the tadpoles too create PGE2.
*** The mucus excreted from the tadpoles' gills contains the PGE2 necessary to maintain the stomach in a non-functional state. *** These mucus excretions do not occur in tadpoles of most other species.
* During the period that the offspring are present in the stomach the frog does not eat.
* Tadpole development takes at least six weeks, during this time the size of the mother’s stomach continues to increase until it largely fills the body cavity.
* The lungs of the female deflate and breathing relies more upon gas exchange through the skin.
* Despite the mother's increasing size she still remains active.
* The birth process is widely spaced and may occur over a period of as long as a week.
** However, if disturbed the female may regurgitate all the young frogs in single act of propulsive vomiting.
* The offspring are completely developed when expelled.
= Species Differences =
= Species Differences =