In biology, a life cycle is a series of changes in form that an organism undergoes, returning to the starting state. "The concept is closely related to those of the life history, development and ontogeny, but differs from them in stressing renewal." Transitions of form may involve growth, asexual reproduction, and/or sexual reproduction. In some organisms, different "generations" of the species succeed each other during the life cycle.
More at: Biological life cycle