The life cycle of an organism can be divided into three different phases:
Juvenile or vegetative phase: during this period, the organism achieves basic growth and development becoming a fully functioning individual capable of all basic life processes.
Reproductive or mature phase: In this phase, the organism is ready to reproduce. Entering the reproductive phase is marked by different events in different organisms. In higher plants flowering is the indication for reproductive phase.
Senescence or old age: it is the last phase of the life cycle of an organism, typically marked by the end of reproductive phase and deterioration of different body structures and functions etc