Reproductive System :
Frog is unisexual i.e. male and female reproductive organs are found in separate animals. Frog exhibits distinct sexual dimorphism.
Male Reproductive System :
The male reproductive system includes following organ-
(i) Testes : There is a pair of testes with are oval, yellow in color and are attached to the anterior-outer side of the kidneys. Each testis consists of many seminiferous tubules which are the structural and functional unit of the testis. The testes form the male gametes called sperms and the process of sperm formation is called as spermatogenesis.
(ii) Vas efferentia & Bidder’s Canal : The testis gives out 10-12 minute Vas efferentia which enter into the respective kidney and open into a Bidder’s canal. The Bidder’s canal is found inside the kidney and it in tum opens into the ureter (urinogenital duct).
In male frog, the urinogenital duct transports both the sperms & urine. Both the urinogenital ducts open separately into the cloaca.
Female Reproductive System :
In female frog, the kidneys are similar to the male kidney but they are not concern with the reproduction. The female reproductive system consists of-
- Ovaries : There is a pair of large, branched and yellow ovaries which are attached to the kidneys superficially only. The form ova by the process of oogenesis. The mature ova are released into the body cavity.
- Oviducts : There is a pair of long, coiled and glandular oviducts or Mullerian ducts. The anterior end of the oviduct is funnel shaped and called as ostium. The middle part is thin and coiled. The posterior part modifies to form an ovisac which temporarily stores the ova. Both the ovisacs open separately into the cloaca.
Physiology of Reproduction :
The frog is a seasonal breeder and it breeds in rainy season. A mature female lays about 2500 to 3000 eggs in a spawn. The eggs are mesolecithal having size about 1 to 2 mm.
The fertilization is external and development is indirect. The larva is tadpole larva. The tadpole larva metamorphoses to form young frog.
