Functional Morphology of Reproductive Organs
Previously you have learnt about the essential features of sexual reproduction. In, this we shall learn about .the organs of reproduction: The organs that produce germ cells are known as gonads. The gonads that produce the sperm are called testis and that which form the eggs is known as the ovary.
Gonads are the primary sex organs found in ail the animals. In some primitive animals the gamete-producing tissues are diffuse, consisting of numerous scatted loci for the proliferation of sex cells. In all the more advanced animals the gonads are localised, and in the bilaterally symmetrical animals they arise as paired structures. Sometimes one of the gonads degenerates secondarily. The birds provide a familiar example with paired testis in the male and a single left ovary in most females.