A life cycle is a fixed period of time that repeats regularly in the life of a living organism.
The life cycle of a person is from birth todeathIn the series of processes up todevelopmentIt refers to the sequence of stages and the cycle of generations. The human life cycle has often been likened to the seasons, with childhood and adolescence as stages of growth in spring, maturity in summer, middle age (menopause) in fall, and old age, which is a period of decline, in winter. The term became widely popular after psychoanalyst and developmental psychologist E.H. Erikson and others discussed it in their book, "The Life Cycle, Its Completion. In addition, Erikson,human beingFocusing on the aspect of the ego, life is divided into eight stages (infancy, early childhood, late infancy, childhood, adolescence, early adulthood, mature adulthood, and old age), and each stage has its own problems to be solved (developmentissues), and the previous phase of thedevelopmentThe issue is the next stage of thedevelopmentpsychological and social that it is the basis of the stage.developmentThe stages were shown.
On the other hand, life course, which describes specific life characteristics, and life span, which describes the length of life, are different concepts from life cycle in that they are terms that focus on the way an individual person lives and do not include generations.

References
(1) Erik H. Erikson, Joan M. Erikson (Author) / Takao Murase, Kunio Kondo (Translators): Life Cycle, Its Completion, Supplement Edition, Misuzu Publishing, 2001.
(2) Paul Tournier (Author) / Yasuko Miura (Translator): Four Seasons of Life: Development and Maturity, Japan Christian Press, 2007.
(3) Baba, Reiko and Nagai, Removal (eds.): Clinical Psychology of Life Cycle, Baifukan, 1997.