Lesson 10 of 11 · 10 min
Reproduction and development
NCERT §7.2.2
After a night of heavy rain Arjun finds floating masses of jelly-coated eggs in the pond. Ms Rao asks him to estimate how many one female lays.
The lesson in notes
In short
The male reproductive organs are a pair of yellowish, ovoid testes, attached to the upper part of the kidneys by a double fold of peritoneum called the mesorchium.
Ten to twelve vasa efferentia leave the testes and pass into the kidney on the same side, where they open into Bidder's canal. Bidder's canal connects with the urinogenital duct coming out of the kidney, and this duct opens into the cloaca.
The cloaca is a small median chamber through which faecal matter, urine and sperms all pass to the outside.
The female reproductive organs are a pair of ovaries lying near the kidneys, with no functional connection to them. A pair of oviducts arising from the ovaries opens into the cloaca separately.
A mature female lays 2500 to 3000 ova in one go.
Fertilisation is external and happens in water. Development includes a larval stage, the tadpole, which undergoes metamorphosis to become the adult.
Frogs are useful to people: they eat insects and so protect crops, and they are an important link in food chains and food webs, keeping the ecosystem in balance. In some countries their muscular legs are eaten.