You have learnt about structure and function of the reproductive organs. In this we-shall learn about the reproductive activities. Gamete production is not a continuous phenomenon. It is recurring and cyclical. In most of the animals maturation of the gametes takes place during the seasons which are most favourable for the development and growth of the young. Based on the frequency of gamete maturation followed by breeding activity, animals are termed as annual breeders, biannial breeders and so on. Most of the non-mammalian vertebrates exhibit annual reproductive cycle.
The gonads of such animals mature once in a year and hence they reproduce once in a year. Studies have shown that it is the ovary which exhibits gamete differentiation in phases whereas spermatogenesis is a continuous process.