The concept of life cycle can be used in different areas. In biology, life cycle means the alternation of generations. Other words, in eukaryotes, sexual reproduction exhibits an alternation of nuclear phases: meiosis derives in a haploid phase and the fusion of gametes produces a diploid phase.
Marketing uses the concept of life cycle to analyze the conditions of a product on the market. That said, a product goes through several steps from birth until the end (when it ceases to be made/produced).
During its development, the product is enough as long as it generates no revenue. From its placing on the market, the product begins to be sold though with a relatively low level of sales. With its growth, the costs start to decline by the large scale production and profits increase. The cycle continues with a stage of maturation where the highest levels of sales and profitability are met. Then comes the stage of decline, or when sales, prices and profits fall.
Concerning the environment, the life cycle is a concept that allows us to measure the environmental impact of a product from the moment its materials are extracted from nature until they return as waste.
Finally, for engineering and information technology, the development cycle is the period which begins with the implementation of a technological standard and ends with the development of new more effective instruments.