Animals may develop, grow and live a normal life span without reproducing. However, the continuance of the species and all evolutionary changes would come to an end without reproduction.
Reproduction is a process by which organisms constantly replace the old with similar but somewhat variable offspring. Successful reproduction in fact is the ultimate objective of all life processes. In this Unit you shall study various reproductive mechanisms, functional morphology of reproductive organs, the process of gametogenesis, hormones of reproduction, breeding cycles and also about regulation of reproduction.