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Life cycle

A '''life cycle''' is a series of changes an organism, product, project, or other entity undergoes from its inception through development, operation, and termination. The term is used across various disciplines to describe cyclical or sequential processes. In biology, it refers to the sequence of developmental stages an organism passes from formation to death, often involving reproduction.^[1] The concept extends to other fields, including:

Natural sciences: Biological and ecological life cycles.
Engineering and technology: Product life cycles, software development life cycles, and systems engineering life cycles.
Business and management: Business life cycles and project life cycles.
Social sciences: Human and family life cycles.
Arts and entertainment: Representations in literature, film, music, and performing arts.
Other uses: In mythology, religion, and miscellaneous applications.

For detailed discussions, see the relevant sections below.

Natural Sciences

Biological Life Cycles

The biological life cycle encompasses the sequence of developmental and physiological changes an organism undergoes from its inception through maturity, reproduction, and eventual death. This process typically includes key stages: origin via birth, hatching, or germination; growth and maturation involving cellular division, organ formation, and physiological development; reproduction to propagate the species; senescence marked by declining physiological function; and death. These stages vary across taxa but universally reflect adaptations to environmental pressures and evolutionary imperatives.^[2]^[3]^[1] In animals, life cycles often feature distinct metamorphic phases, as exemplified by holometabolous insects like butterflies, which undergo complete metamorphosis with four stages: egg, larva (caterpillar), pupa (chrysalis), and adult. During the larval stage, the organism focuses on rapid growth and feeding, while the pupal stage involves profound tissue reorganization into the reproductive adult form. In contrast, hemimetabolous insects, such as grasshoppers, exhibit incomplete metamorphosis, progressing through egg, multiple nymphal instars resembling miniature adults, and adult stages without a pupal phase. A striking example of abbreviated adult duration occurs in mayflies (order Ephemeroptera), where aquatic nymphs develop for a few months to three years, but the terrestrial adult phase lasts only a day or so, primarily dedicated to mating.^[4]^[5]^[6]^[7] Plant life cycles differ markedly, often spanning annual or perennial patterns and incorporating alternation of generations between haploid gametophyte and diploid sporophyte phases. Annual plants, such as marigolds, complete their entire cycle—from seed germination through growth, flowering, seed production, and death—within one growing season, enabling rapid exploitation of favorable conditions. Perennial plants, like oaks, persist for multiple years, with vegetative growth continuing beyond reproduction, allowing resource accumulation over time. The alternation of generations ensures genetic diversity, as the gametophyte produces gametes via mitosis and the sporophyte generates spores via meiosis.^[8]^[9] Evolutionary adaptations enhance survival across these cycles, such as seed dormancy in plants, which delays germination until environmental cues like moisture and temperature signal viability, preventing premature sprouting in harsh conditions. Similarly, diapause in insects—a state of arrested development—allows overwintering or drought resistance, as seen in many species responding to photoperiod or temperature shifts, thereby synchronizing life stages with seasonal opportunities. These mechanisms underscore the life cycle's role in population persistence amid varying ecological dynamics.^[10]^[11]

Ecological Life Cycles

Ecological life cycles describe the dynamic progression of biological communities within ecosystems, primarily through the process of ecological succession, where species composition and habitat structure evolve over time toward a stable climax community. Primary succession begins on newly exposed, barren substrates such as bare rock or lava flows, starting with pioneer species like lichens and mosses that initiate soil formation, followed by herbaceous plants, shrubs, and eventually trees that form a mature forest.^[12] Secondary succession occurs after disturbances that remove vegetation but leave soil intact, allowing faster recovery through recolonization by existing seed banks and nearby propagules, progressing from grasses and forbs to woody perennials and climax vegetation.^[13] Central to these cycles are nutrient cycling and energy flow, which sustain community development and stability. Nutrient cycling involves the continuous movement of essential elements like carbon and nitrogen through ecosystems via biological, geological, and chemical pathways; for instance, the carbon cycle includes atmospheric fixation by photosynthesis, uptake by producers, consumption across trophic levels, and return to the atmosphere through respiration and decomposition.^[14] The nitrogen cycle similarly features fixation of atmospheric N₂ by bacteria into ammonia, nitrification to nitrates for plant assimilation, denitrification back to N₂, and decomposition of organic matter to release ammonium.^[14] Energy flow occurs unidirectionally through trophic levels in food webs, from primary producers (e.g., plants and phytoplankton) at the base, to herbivores, carnivores, and apex predators, with approximately 10% efficiency of transfer between levels due to losses in metabolism and waste.^[15] Illustrative examples highlight these processes in action. In forest succession, pioneer herbs and grasses colonize disturbed sites, stabilizing soil and providing habitat for insects and small mammals, eventually giving way to shade-tolerant climax trees like oaks or hemlocks that dominate the mature canopy.^[13] In marine ecosystems, plankton life cycles—particularly phytoplankton blooms driven by nutrient upwelling—underpin oceanic primary productivity, converting solar energy into biomass that supports vast food webs from zooplankton to fish and whales.^[16] Keystone species, such as sea otters in kelp forests or wolves in terrestrial habitats, disproportionately influence cycle stability by regulating populations of key prey or competitors, preventing dominance by a single species and maintaining biodiversity.^[17] Disturbances like wildfires or floods can reset these cycles by clearing biomass, promoting secondary succession and enhancing long-term resilience through renewed diversity.^[13] Mathematical models like the Lotka-Volterra equations capture oscillatory dynamics in predator-prey interactions that underpin population cycles within ecological life cycles. The basic model consists of two coupled differential equations for prey population x and predator population y:

\frac{dx}{dt} = \alpha x - \beta x y

\frac{dy}{dt} = \delta x y - \gamma y

Here, \alpha is the intrinsic growth rate of the prey in the absence of predators, \beta is the predation rate (encounters per predator-prey pair), \delta is the predator's growth efficiency from consuming prey, and \gamma is the predator's natural death rate. To derive these, start with the prey equation assuming Malthusian exponential growth (\alpha x) reduced by predation proportional to encounter frequency (\beta x y); for predators, growth depends on prey consumption (\delta x y) minus exponential death (\gamma y). These nonlinear equations yield periodic oscillations around an equilibrium point (\gamma/\delta, \alpha/\beta), illustrating how predator-prey feedback drives cyclic fluctuations in populations, as observed in real ecosystems like lynx-hare dynamics.^[18]

Engineering and Technology

Product Life Cycle

The product life cycle (PLC) refers to the sequence of stages that a product undergoes from its initial development to its eventual withdrawal from the market, typically encompassing introduction, growth, maturity, and decline. This concept was originally proposed by Theodore Levitt in his 1965 Harvard Business Review article, where he emphasized exploiting these stages for competitive advantage through strategic marketing adjustments.^[19] The PLC framework helps manufacturers and marketers anticipate changes in sales, competition, and consumer behavior, enabling informed decisions on pricing, promotion, and distribution. While the duration of each stage varies by industry and product type, the model provides a predictive tool for resource allocation across the product's lifespan.^[20] The PLC begins with the development stage, involving research and development (R&D), prototyping, and testing to refine the product concept before market entry. This phase focuses on innovation and feasibility assessment, often incurring high costs with no revenue generation. Following development, the introduction stage marks the product's market launch, characterized by low sales volumes, heavy promotional investments to build awareness, and typically high pricing to recover initial costs. As demand increases, the growth stage sees rapid sales acceleration, allowing for production scaling, expanded distribution, and potential price reductions to capture market share amid rising competition. The maturity stage arrives when sales peak and stabilize, with intense rivalry leading to differentiation efforts like feature enhancements; profitability is often highest here due to economies of scale. Finally, the decline stage involves falling sales due to market saturation, technological obsolescence, or shifting preferences, prompting decisions such as discontinuation, revitalization through rebranding, or harvesting via cost-cutting to maximize remaining profits.^[21]^[22] Key metrics in the PLC include sales volume curves, which often follow an S-shaped growth model during the introduction and growth stages—starting slowly, accelerating steeply, and then plateauing—reflecting cumulative market adoption patterns. Profitability analysis varies by stage: negative or low in development and introduction due to upfront investments, rising sharply in growth as revenues outpace costs, peaking in maturity, and diminishing in decline unless mitigated by strategies like product extensions. These metrics guide tactical shifts, such as aggressive advertising in growth or defensive pricing in maturity.^[23]^[24] A prominent example is the evolution of smartphones, particularly Apple's iPhone series, where each model progresses through the PLC: the original iPhone (2007) experienced slow introduction sales before explosive growth, reaching maturity with iterative updates like the iPhone 4 and 5, and employing extension strategies such as software enhancements to delay decline. In the decline phase, companies may pursue harvesting by reducing marketing spend or revitalization via rebranding, as seen with older iPhone models phased out in favor of newer iterations. Environmental considerations are increasingly integrated into the PLC through cradle-to-grave assessments, evaluating a product's impacts from raw material extraction to disposal for sustainability; this aligns with standards like ISO 14001, which requires organizations to consider life cycle perspectives in environmental management systems to minimize ecological footprints.^[25]^[26]

Software Development Life Cycle

The Software Development Life Cycle (SDLC) is a structured framework that outlines the phases involved in planning, creating, testing, deploying, and maintaining software systems to ensure they meet user needs efficiently and reliably.^[27] This methodology encompasses key stages such as requirements analysis, design, implementation, testing, deployment, and maintenance, providing a systematic approach to manage complexity and reduce risks in software projects.^[28] Originating from efforts to formalize software engineering practices, the SDLC has evolved to accommodate diverse project scales, from small applications to large enterprise systems, emphasizing quality, cost control, and timely delivery.^[27] One of the earliest formalized SDLC models is the Waterfall approach, introduced by Winston W. Royce in 1970 as a linear, sequential process where each phase must be completed before the next begins.^[29] In this model, progress flows downward like a waterfall through requirements gathering, system design, implementation, verification, and maintenance, making it suitable for projects with well-defined, stable specifications.^[29] However, its rigidity has led to adaptations in modern contexts, where feedback loops are often incorporated to address unforeseen changes. In contrast, Agile methodologies represent a shift toward iterative and incremental development, prioritizing flexibility and customer collaboration as outlined in the 2001 Agile Manifesto.^[30] Agile breaks projects into short sprints—typically 1-4 weeks—allowing teams to deliver functional increments rapidly and incorporate feedback continuously.^[30] A prominent Agile framework is Scrum, which defines roles such as the Product Owner (responsible for prioritizing features via a product backlog), Scrum Master (facilitating the process), and Development Team, along with events like daily stand-ups and sprint reviews to foster transparency and adaptability.^[31] Complementing Agile, DevOps practices integrate development and operations for continuous delivery, automating the pipeline from code commit to production deployment to enable frequent, reliable releases.^[32] The SDLC stages provide a detailed roadmap for execution across models. Requirements gathering involves eliciting and documenting user needs, often through techniques like user stories in Agile to capture functional and non-functional specifications clearly.^[28] Design follows, translating requirements into architectural blueprints, including high-level system structures and detailed component interfaces. Implementation, or coding, entails writing source code using programming languages such as Python or Java, supported by version control systems like Git to track changes and enable collaborative development.^[28] Testing verifies the software through unit tests (for individual modules), integration tests (for component interactions), and metrics like code coverage (aiming for 80% or higher to ensure robustness).^[28] Deployment releases the software to production environments, while maintenance addresses post-deployment updates, including bug fixes, enhancements, and scalability improvements to sustain long-term viability.^[28] The SDLC traces its roots to the 1960s, amid the "software crisis" of escalating complexity in large-scale systems, which spurred the adoption of structured programming principles to promote modularity, readability, and error reduction through constructs like sequences, selections, and iterations. These foundations influenced subsequent methodologies, evolving from rigid structures to iterative paradigms by the 1990s and 2000s. As of 2025, trends include AI-assisted coding tools like GitHub Copilot, which use large language models to suggest code completions and boost developer productivity by up to 55% in routine tasks.^[33]^[34] Low-code platforms, enabling rapid application development via visual interfaces, are also gaining traction, projected (as of a 2021 Gartner report) to account for over 70% of new business applications by 2025, democratizing software creation beyond traditional programmers.^[35] To estimate SDLC costs and efforts, models like the Constructive Cost Model (COCOMO), developed by Barry W. Boehm in 1981, provide parametric predictions based on project attributes.^[36] In its basic form for organic projects (small teams with flexible requirements), effort in person-months is calculated as:

\text{Effort} = a \times (\text{KLOC})^b

where KLOC is thousands of lines of code, and for organic mode, a = 2.4 and b = 1.05.^[36] This equation derives from empirical data on 63 projects, scaling effort nonlinearly with size; for example, a 10 KLOC project requires approximately 2.4 × (10)^1.05 ≈ 28 person-months, highlighting the model's utility in early planning while accounting for development mode variations like semi-detached or embedded projects with different coefficients.^[36]

Systems Engineering Life Cycle

The systems engineering life cycle encompasses the end-to-end processes for developing, operating, maintaining, and retiring complex systems, as defined by the ISO/IEC/IEEE 15288:2023 standard, which provides a common framework for system life cycle processes including stakeholder needs evaluation, system architecture development, verification, validation, and disposal activities.^[37] This standard, updated in 2023, emphasizes interdisciplinary integration across technical, management, and enabling processes to ensure systems meet user requirements throughout their lifespan.^[38] The life cycle is typically structured into key stages: the Concept stage, which involves feasibility studies and initial requirements gathering; the Development stage, focusing on detailed design, integration, and testing; the Production/Utilization stage, covering manufacturing, deployment, and operational use; the Support stage, dedicated to maintenance, upgrades, and logistics; and the Retirement stage, addressing decommissioning and disposal to minimize environmental impact. These stages align with the process categories in ISO/IEC/IEEE 15288:2023, such as technical management and technical processes, allowing for tailored application in various domains.^[37] Central to the life cycle are key concepts like the V-model, which illustrates a sequential development process where verification (ensuring the system is built correctly) and validation (ensuring the right system is built) occur in parallel to design and integration phases, promoting traceability from requirements to testing. Risk management is another cornerstone, often employing Failure Mode and Effects Analysis (FMEA), a systematic method to identify potential failure modes, assess their severity (S, rated 1-10), occurrence likelihood (O, rated 1-10), and detection probability (D, rated 1-10), and calculate a Risk Priority Number (RPN = S × O × D) to prioritize mitigation actions. In practice, the life cycle is applied to aerospace systems, such as NASA's mission projects, where phases from concept exploration to operations and closeout ensure reliable integration of hardware, software, and human elements, as outlined in the NASA Systems Engineering Handbook.^[39] Modern advancements include model-based systems engineering (MBSE), which uses the Systems Modeling Language (SysML) to create digital representations of systems for simulation and analysis, enhancing collaboration and reducing errors compared to document-based approaches. Historically, systems engineering traces its roots to the 1950s at Bell Labs, where the term emerged during the design of complex telephone switching systems, marking the shift from component-focused to holistic system integration.^[40] As of 2025, emerging trends incorporate digital twins—virtual replicas of physical systems—for real-time simulation and predictive maintenance, improving life cycle efficiency in domains like manufacturing and infrastructure.^[41]

Business and Management

Business Life Cycle

The business life cycle refers to the progression of stages that an organization typically undergoes from its formation to potential dissolution, encompassing phases of startup, growth, maturity, and renewal or decline. This concept is foundational in management theory, providing a framework for understanding organizational evolution and strategic needs at each juncture. One influential model is Ichak Adizes' Corporate Life Cycle, introduced in 1979, which posits that businesses, like living organisms, experience predictable developmental patterns influenced by internal dynamics and external factors.^[42] Adizes' framework emphasizes balancing entrepreneurial flexibility with administrative control to navigate these stages effectively, avoiding premature decline.^[43] In the Existence stage, the focus is on idea validation and securing initial funding, where founders test market viability and build a minimum viable product amid high uncertainty and resource constraints.^[44] This corresponds to Adizes' Infancy and early Go-Go phases, characterized by rapid experimentation but vulnerability to cash flow issues. The Survival stage follows, centering on achieving break-even operations through operational efficiencies and customer acquisition, often requiring additional capital to stabilize the venture.^[45] Here, businesses confront scaling challenges, with failure rates peaking due to inadequate management structures. Success marks the transition to consistent profitability, where the organization refines its core competencies and establishes a stable market position, aligning with Adizes' Adolescence phase of controlled expansion.^[43] The Take-off stage involves aggressive expansion, such as entering new markets or scaling operations, demanding robust leadership to manage increased complexity.^[44] Resource Maturity emerges next, where bureaucracy begins to emerge as a risk, with formalized processes supporting efficiency but potentially stifling innovation if not monitored.^[45] In the Aristocracy stage, stagnation sets in as complacency grows among leadership, leading to a focus on preservation over adaptation. Recrimination follows, marked by internal conflicts and blame-shifting amid declining performance, eroding morale and cohesion.^[43] Bureaucracy intensifies inefficiencies through rigid hierarchies and risk aversion, culminating in the Death stage of closure, often via bankruptcy or acquisition, unless renewal intervenes.^[44] Key strategies vary by stage: during growth phases like Take-off, pivoting—such as shifting business models based on market feedback—helps sustain momentum, as seen in tech startups adapting to user data. In maturity, diversification through product line extensions or geographic expansion mitigates stagnation risks. Turnaround tactics in decline, including mergers for resource infusion or cost restructuring, can facilitate renewal, with successful cases showing improved operational efficiency post-intervention. Illustrative examples include tech startups like Amazon, which progressed from startup in 1994 (Existence and Survival, focusing on online bookselling and funding rounds) to rapid growth in the late 1990s (Success and Take-off, with revenue surging from $148 million in 1997 to $1.64 billion in 1999, a 1000%+ increase), and into maturity by the 2010s (Resource Maturity, with diversified segments like AWS driving sustained 20-40% annual revenue growth through 2020).^[46] Economic cycles profoundly influence this progression; recessions accelerate decline in vulnerable stages like Survival, while booms fuel Take-off, as evidenced by heightened startup funding during expansions like the post-2008 recovery. As of 2025, renewals increasingly incorporate sustainability via ESG integration, enabling mature firms to pivot toward green practices for regulatory compliance and investor appeal, with studies showing ESG-engaged companies are more likely to advance from maturity to renewed growth.^[47] This shift addresses decline risks by aligning with global demands for ethical operations, as seen in corporate strategies emphasizing carbon reduction and supply chain transparency.^[48]

Project Life Cycle

The project life cycle refers to the series of phases a project passes through from its initiation to completion, providing a structured framework for managing temporary endeavors to deliver unique products, services, or results. As outlined in PMI's project management standards, including the five key process groups (initiation, planning, execution, monitoring and controlling, and closing) contextualized in the PMBOK framework (7th edition, 2021), these phases guide project managers in aligning resources and activities to achieve defined objectives. These phases ensure systematic progression, risk mitigation, and stakeholder satisfaction, distinguishing project management from ongoing operational activities.^[49] In the initiation phase, the project is formally authorized through the development of a project charter, which outlines the project's objectives, high-level requirements, and key assumptions. This document is typically approved by the project sponsor and identifies initial stakeholders—individuals or groups affected by or influencing the project, such as clients, team members, and executives—enabling early engagement to build support and clarify expectations. Stakeholder analysis during this phase helps prioritize their needs and influence, setting the foundation for effective communication throughout the life cycle.^[50] The planning phase involves creating a detailed project management plan that defines the scope, schedule, budget, and resources required for success. Scope planning establishes what the project will deliver, often using work breakdown structures to decompose deliverables into manageable tasks. Scheduling tools like Gantt charts visualize timelines by displaying tasks as horizontal bars against a calendar, highlighting dependencies and milestones to forecast completion dates. Budget planning estimates costs and allocates funds, while risk registers—a documented list of potential risks including their probability, impact, and response strategies—are developed to proactively address uncertainties.^[51]^[52]^[53] During the execution phase, the project plan is put into action through directing and managing work, including coordinating teams to perform assigned tasks and procuring necessary resources. Project managers facilitate team collaboration, resolve issues, and ensure deliverables meet quality standards, often using communication plans to keep stakeholders informed of progress. This phase emphasizes leadership to motivate teams and adapt to emerging challenges while implementing approved changes.^[54] The monitoring and controlling phase runs concurrently with execution, involving ongoing oversight to track performance against the plan and implement corrective actions. Techniques like earned value management (EVM) quantify progress by calculating earned value (EV) as the percentage of work completed multiplied by the budget at completion (BAC), allowing managers to assess cost and schedule variances—for instance, if a task is 40% complete with a $100,000 BAC, EV equals $40,000. The Critical Path Method (CPM) identifies the longest sequence of dependent tasks determining the project's minimum duration, using forward pass calculations to determine early start and finish times (adding durations and considering dependencies) and backward pass to find late times (subtracting from the project end date), thus highlighting tasks with zero float that require close attention.^[55]^[56] Finally, the closing phase formalizes project completion by obtaining stakeholder acceptance of deliverables, releasing resources, and archiving records. This includes conducting lessons learned sessions to document successes, challenges, and recommendations for future projects, as well as handover activities to transfer outputs to operations or clients, ensuring smooth transition and contract closure. Proper closure reinforces organizational knowledge and celebrates achievements.^[57] Key tools like CPM and EVM provide quantitative insights for decision-making, while risk registers support ongoing threat identification. In practice, construction projects exemplify the life cycle through sequential phases, such as site preparation in initiation and structural building in execution, often relying on Waterfall approaches for regulatory compliance. Software projects frequently adapt the model with Agile elements, incorporating iterative sprints within execution to handle evolving requirements while retaining core monitoring via EVM. As of 2025, hybrid methodologies blending Waterfall's structure with Agile's flexibility are increasingly adopted to balance predictability and adaptability in complex environments.^[58]^[59]^[60]

Human Life Cycle

The human life cycle encompasses the biological, psychological, and social progression of an individual from birth through death, typically divided into stages such as infancy, childhood, adolescence, adulthood, and old age. This lifespan model integrates physical maturation with psychosocial development, as outlined in Erik Erikson's theory of eight sequential stages influenced by biological, psychological, and social factors across the lifetime.^[61] Erikson's psychosocial stages emphasize conflicts that shape personality and social adaptation at each phase. In infancy (ages 0-2), the core conflict is trust versus mistrust, where consistent caregiving fosters a sense of security. Early childhood (ages 3-5) involves initiative versus guilt, as children explore autonomy through play and social interactions. Preschool years (ages 5-12) focus on industry versus inferiority, building competence via school and peer experiences. Adolescence (ages 12-18) centers on identity versus role confusion, navigating self-concept amid societal expectations. Young adulthood (ages 18-40) addresses intimacy versus isolation, forming deep relationships. Middle adulthood (ages 40-65) features generativity versus stagnation, contributing to society through work and family. Late adulthood (65+) confronts integrity versus despair, reflecting on life's meaning.^[61] Key physical milestones include puberty, which typically begins around ages 12-14, marking the transition to reproductive maturity with hormonal changes like increased estrogen and testosterone production. Cognitive development, as described by Jean Piaget, progresses through four stages: sensorimotor (birth to 2 years), where infants learn via sensory experiences and motor actions; preoperational (2-7 years), characterized by symbolic thinking but egocentrism; concrete operational (7-11 years), enabling logical thought about concrete events; and formal operational (12+ years), allowing abstract and hypothetical reasoning.^[62]^[63] Global average human lifespan trends show approximately 73.5 years as of 2025, reflecting improvements in healthcare, nutrition, and sanitation, though variations exist by region and socioeconomic factors. In aging, telomere shortening contributes to cellular senescence, as protective chromosome endcaps erode with each cell division, accelerating age-related decline in tissue repair and increasing disease susceptibility.^[64]^[65] Cultural influences shape stage interpretations, with some societies emphasizing communal roles in adolescence or extended family support in old age, altering the timing and significance of transitions. A modern extension, emerging adulthood (ages 18-29), describes a prolonged period of identity exploration, instability, and self-focus in industrialized cultures, distinct from traditional adolescence or full adulthood. Family dynamics can modulate these stages by providing emotional buffers during conflicts like identity formation.^[66]^[67]

Family Life Cycle

The family life cycle refers to the developmental stages that family units undergo from formation to dissolution, as conceptualized in Evelyn Duvall's 1977 model in her book Marriage and Family Development. This framework outlines eight sequential stages based on factors such as the age of the oldest child, family size, and role transitions, emphasizing how families adapt to changing structures and tasks over time.^[68] Duvall's model highlights the progression from establishment to aging, focusing on normative patterns in nuclear families while acknowledging variations due to individual circumstances.^[69] The stages begin with the newly married couple without children, where the focus is on establishing marital roles and adjusting to shared living.^[70] This is followed by the childbearing stage, involving the birth of the first child and early parenting demands with infants.^[71] Next comes the preschool stage (ages 3-6), marked by increased family activities and child socialization; the school-age stage (6-13), emphasizing education and extracurricular involvement; and the teenage stage (13-20), dealing with adolescent independence and family conflicts.^[72] The launching stage involves children leaving home, leading to the empty nest; the middle years feature post-parental adjustments and career peaks; and the aging stage encompasses retirement, grandparenting, and eventual widowhood.^[69] Key dynamics in the family life cycle include shifting roles, such as from active parenting to grandparenting, which foster intergenerational support but can strain resources.^[73] Stressors like divorce disrupt these transitions, with approximately 41% of first marriages in the United States ending in divorce, often during childbearing or launching stages due to financial pressures or relational strains.^[74] Cultural differences influence these patterns; for instance, extended family structures remain more common in Asia than in the West; in Thailand, 37% of households are extended families including multiple generations (as of 2020, UNFPA), while in China, three-generation households account for about 16% (as of 2010 census data, with trends indicating further decline).^[75]^[76] As of 2025, delayed marriage—now averaging age 28.6 for women and 30.2 for men in the U.S.—compresses childbearing timelines, leading to smaller families and increased reliance on fertility technologies like AI-assisted IVF for conception in later stages.^[77]^[78] These advancements, including non-invasive genetic testing, enable family expansion for couples in middle years who postponed formation due to career priorities.^[79] Attachment theory, originally developed by John Bowlby, applies to family bonds by explaining how secure early parent-child attachments influence lifelong family cohesion and resilience during transitions like launching or aging.^[80]^[81]

Arts and Entertainment

In Literature and Film

In literature and film, the life cycle serves as a recurring motif that encapsulates the stages of birth, growth, transformation, decline, and death, often symbolizing broader themes of impermanence, renewal, and the inexorable passage of time. This motif draws from natural rhythms, such as seasonal changes or biological processes, to explore human existence and existential questions, providing a framework for characters' arcs and narrative progression. Authors and filmmakers employ it to underscore mortality and continuity, creating emotional resonance through patterns that mirror life's inevitable transitions. One prominent literary depiction appears in William Shakespeare's As You Like It (1599), where the character Jaques delivers the monologue "All the world's a stage," outlining the "seven ages of man" from infancy—mewling and puking in the nurse's arms—to second childishness and mere oblivion in old age, portraying life as a theatrical progression of inevitable stages. This speech illustrates the life cycle as a universal human journey, blending humor and pathos to reflect on aging and fate. Similarly, Gabriel García Márquez's One Hundred Years of Solitude (1967) weaves family lineage cycles across seven generations of the Buendía family in the fictional town of Macondo, where events and character traits repeat in a cyclical pattern, emphasizing themes of isolation, repetition, and historical inevitability through magical realism. These repetitions highlight how personal and familial lives echo larger existential loops, culminating in the town's destruction.^[82]^[83] In film, the motif manifests through visual and structural storytelling, as seen in Disney's The Lion King (1994), where the "Circle of Life" song and narrative arc follow young Simba's journey from birth and exile to kingship, paralleling animal life cycles in the African savanna to explore inheritance, loss, and ecological balance. The hero's journey reinforces transformation, with Mufasa's death and return symbolizing renewal amid mortality. Richard Linklater's Boyhood (2014), filmed over 12 years, chronicles the real-time development of protagonist Mason from age six to eighteen, capturing mundane milestones like family shifts and personal growth to depict the human life cycle's gradual unfolding without dramatic exaggeration. This approach emphasizes authentic progression, highlighting how everyday experiences shape identity across stages.^[84]^[85] Archetypal criticism, notably Northrop Frye's framework in Anatomy of Criticism (1957), interprets the life cycle through seasonal analogies: spring for comedic renewal, summer for romantic ascent, autumn for tragic decline, and winter for ironic detachment, mapping literary genres onto organic and cosmic rhythms to reveal universal patterns in storytelling. Filmmakers and writers often employ techniques like circular narratives—where stories loop back to their origins, as in One Hundred Years of Solitude's prophetic ending—or flashbacks to depict cyclical depictions, compressing or revisiting life stages for thematic depth and to evoke the motif's transformative essence.^[86] By 2025, eco-themed films increasingly integrate life cycle narratives to address climate change, portraying disrupted natural and human cycles through stories of environmental collapse and resilience, such as documentaries at the One Earth Film Festival exploring adaptation in vulnerable ecosystems. These works use the motif to warn of interrupted renewals, blending human development with planetary fate for urgent commentary.^[87]

In Music and Performing Arts

In music and performing arts, the life cycle is thematically explored through rhythmic structures, lyrical narratives, and performative sequences that often mirror the cyclical progression of seasons, emphasizing stages from inception to renewal or cessation. Composers and artists employ these elements to evoke the passage of time, personal growth, and existential transitions, drawing audiences into reflective experiences that parallel natural and human rhythms.^[88] A prominent example in classical music is Gustav Mahler's Symphony No. 3, composed between 1893 and 1896, which traces life's evolution from elemental nature and childhood innocence to mature human consciousness and spiritual affirmation across its six movements.^[89] In folk and singer-songwriter traditions, Joni Mitchell's "The Circle Game," written in 1966 and featured on her 1970 album Ladies of the Canyon, depicts the rites of passage from youth to adulthood through a carousel metaphor, underscoring the relentless, circular flow of time and change.^[90] In contemporary hip-hop, Kendrick Lamar's 2017 album DAMN. incorporates tracks like "FEAR.," which dissects anxieties across life's phases—from childhood fears to adult responsibilities—reflecting ongoing personal evolution in his discography up to the 2024 release of GNX.^[91] In performing arts, Igor Stravinsky's ballet The Rite of Spring, premiered in 1913, portrays a pagan ritual cycle culminating in a sacrificial dance that symbolizes seasonal renewal through the death of a chosen maiden, blending primal rhythms with themes of birth, fertility, and rebirth.^[92] Thornton Wilder's play Our Town, first staged in 1938, structures its three acts as vignettes of daily life in Grover's Corners, progressing from birth and youth in Act I, through love and marriage in Act II, to death and reflection in Act III, where the deceased Emily revisits her past to contemplate mortality's quiet profundity.^[93] Richard Wagner's operatic tetralogy Der Ring des Nibelungen, composed from 1848 to 1874 and totaling over 15 hours, unfolds an epic narrative arc of creation, conflict, downfall, and cosmic renewal, using interconnected stories across four operas to explore human and divine life trajectories.^[94] Central to these works are repetitive motifs, such as Wagner's leitmotifs—recurring musical phrases tied to characters or ideas—that reinforce themes of continuity and renewal, as seen in the forging and destruction of the ring symbolizing inevitable cycles. Performing arts further enhance this through audience immersion, immersing viewers in life-death transitions via direct narrative address, as in Our Town's Stage Manager who breaks the fourth wall to guide reflections on transience, or ritualistic choreography in The Rite of Spring that evokes communal participation in renewal rites.^[95]

Other Uses

In Mythology and Religion

In mythology and religion, life cycles are often depicted as symbolic narratives of creation, existence, death, and rebirth, embodying the cosmic or spiritual order that governs the universe and human destiny. These cycles illustrate the interconnectedness of life and death, where endings precipitate renewal, reflecting profound philosophical insights into existence across diverse cultures. For instance, such motifs underscore the eternal recurrence of natural and spiritual processes, as seen in sacred stories that portray deities or cosmic forces undergoing transformation to maintain harmony.^[96]^[97]^[98] Prominent mythological examples include the Norse Ragnarök, a prophetic cataclysm where the gods battle chaotic forces, leading to the world's destruction by fire and flood, yet culminating in its rebirth from the sea, with new lands emerging for survivors to repopulate. This narrative highlights themes of inevitable doom followed by regeneration, symbolizing resilience amid cosmic upheaval. Similarly, the Egyptian myth of Osiris involves the god's murder and dismemberment by his brother Set, followed by his resurrection through the efforts of his wife Isis, who reassembles his body and revives him, establishing Osiris as the ruler of the underworld and a symbol of fertility and eternal renewal. These stories emphasize death not as finality but as a precursor to restored order.^[99]^[100]^[101]^[102] Religious doctrines further elaborate these cycles through concepts of spiritual progression and liberation. In Hinduism, samsara refers to the perpetual cycle of birth, death, and reincarnation driven by karma, where the soul (atman) transmigrates through various forms until achieving moksha, the release from this wheel of suffering and union with the divine. Christianity, in contrast, centers on the resurrection of Jesus Christ as the pathway to eternal life, promising believers bodily resurrection and everlasting communion with God beyond physical death, transforming the life-death transition into one of ultimate redemption. These frameworks provide moral and existential guidance, portraying life cycles as opportunities for growth or salvation.^[103]^[104]^[105]^[106] Specific cultural artifacts reinforce these ideas, such as the Mayan Long Count calendar, a vigesimal system tracking extended time cycles—with major cycles of 13 baktuns spanning approximately 5,125 years—to align human events with cosmic rhythms of creation and renewal. In Buddhism, the bhavachakra, or Wheel of Life, visually depicts samsara through six realms (gods, demigods, humans, animals, hungry ghosts, and hell beings), propelled by karma and the three poisons of ignorance, attachment, and aversion, illustrating the ceaseless round of rebirth until enlightenment breaks the cycle. Rituals like the Hindu festival of Diwali enact renewal by commemorating the victory of light over darkness, involving the lighting of lamps (diyas) and cleaning of homes to symbolize purification and fresh starts. Scholarship in eco-mythology interprets these cycles environmentally, viewing myths of death and rebirth—such as those in Mesoamerican cultural astronomy and calendars—as metaphors for ecological sustainability and resilience in the face of climate challenges, urging their use in environmental education to foster stewardship.^[107]^[108]^[109]^[110]^[111]^[112]

Miscellaneous Applications

The life cycle concept extends to diverse interdisciplinary fields beyond traditional biological or engineering contexts, encompassing structured processes from inception to termination or renewal in areas such as public policy, urban development, and informatics. These applications emphasize sequential stages that facilitate systematic management, evaluation, and adaptation, often drawing on cyclical models to promote sustainability and efficiency.^[113] In public policy, the life cycle typically comprises stages including agenda setting, policy formulation, implementation, and evaluation, allowing governments to address societal issues methodically while incorporating feedback for iterative improvements.^[114] For instance, agenda setting identifies pressing problems, followed by formulation of potential solutions, execution through legislative or administrative actions, and assessment of outcomes to refine future policies.^[115] Urban planning applies life cycle frameworks to neighborhoods, progressing through phases of development, maturity, decline, and revitalization, as outlined in classic models that inform strategies for sustainable growth.^[116] This approach, originally proposed by Hoover and Vernon in 1959, helps planners anticipate deterioration and intervene with renewal initiatives, such as infrastructure upgrades, to extend urban vitality.^[117] Supply chain management incorporates life cycles from procurement through production, distribution, use, return, remanufacturing, and recycling, particularly in sustainable models that minimize waste.^[118] These stages ensure materials circulate efficiently, with reverse logistics enabling the recovery and repurposing of products to support closed-loop systems.^[119] In education, the curriculum life cycle involves needs assessment, design, development, implementation, and evaluation, enabling educators to align programs with evolving learner requirements and societal needs.^[120] This cyclical process, as detailed in UNESCO guidelines, allows for ongoing refinement, such as updating content based on performance data to enhance educational outcomes.^[121] Emerging in 2025, AI ethics life cycles address responsible deployment by spanning planning, development, bias detection, monitoring, and decommissioning, ensuring systems mitigate harms like algorithmic discrimination throughout their operational span.^[122] Frameworks from organizations like the Inter-Parliamentary Union emphasize documenting these stages to promote transparency and accountability in AI governance.^[123] Circular economy models operationalize life cycles through principles of reduce, reuse, and recycle, forming loops that extend resource lifespan and curb linear "take-make-dispose" patterns.^[124] Pioneered by initiatives like the Ellen MacArthur Foundation, these cycles prioritize design for longevity, such as refurbishment before recycling, to achieve environmental and economic benefits.^[125] Data life cycles in informatics progress from collection and processing to storage, analysis, dissemination, and archiving, providing a blueprint for managing information assets securely and accessibly.^[126] According to NIST guidelines, this structure ensures data integrity across phases, with archiving preserving value for long-term research while complying with retention policies.^[127] In forensic science, insect life cycles, particularly those of blowflies, aid in estimating time of death by analyzing developmental stages—egg, larva, pupa, and adult—on decomposing remains.^[128] Forensic entomologists use temperature-dependent growth rates of these stages to calculate postmortem intervals, as blowflies colonize bodies within minutes, offering precise timelines for investigations.^[129]

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In Daniel Shefer's study, he contends that all neighborhoods go through a life cycle, consisting of periods of growth, stability, deterioration and decay.
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[PDF] CHARLOTTE, NC by Elizabeth Catherine Delmelle A dissertation ...
Related to filtering models are neighborhood life-cycle models developed by economists Hoover and Vernon (1959) who proposed that neighborhoods move through a.
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Supply chains in circular business models: processes and ...
The study indicates that a supply chain in a circular business model consists of eight processes: (1) Plan (2) Source (3) Make (4) Deliver (5) Use (6) Return (7) ...Missing: procurement | Show results with:procurement
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CIPS Procurement and Supply Cycle
The procurement and supply cycle will guide you through the procurement process and will support you every step of the way through your procurement life cycle.
[122]
Training tools for curriculum development: a resource pack
... curriculum “life cycle”. The dimensions are presented here as independent modules that can be read separately or in a circular sequence, starting with any ...
[123]
Training tools for curriculum development: a resource pack
... curriculum “life cycle”. The dimensions are presented here as independent modules that can be read separately or in a circular sequence, starting with any ...
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Data and AI governance: Promoting equity, ethics, and fairness in ...
Aug 5, 2025 · In this paper, we cover approaches to systematically govern, assess and quantify bias across the complete life cycle of machine learning models, ...
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Ethical principles | Inter-Parliamentary Union
Apr 11, 2025 · Highlighting the importance of documenting the entire life cycle of AI systems, from planning to decommissioning, it provides practical ...Missing: detection | Show results with:detection
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Circular economy introduction - Ellen MacArthur Foundation
In a circular economy, products and materials are kept in circulation through processes like maintenance, reuse, refurbishment, remanufacture, recycling, and ...
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[PDF] Circular Economy: The 4Rs reduce-reuse-recycle-recover
Oct 17, 2024 · “The circular economy is a model of production and consumption, which involves sharing, leasing, reusing, repairing, refurbishing, and recycling ...
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8 Steps in the Data Life Cycle - HBS Online - Harvard Business School
Feb 2, 2021 · This life cycle can be split into eight common stages, steps, or phases: Generation; Collection; Processing; Storage; Management; Analysis ...Missing: informatics | Show results with:informatics
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NIST Research Data Framework (RDaF)
Process/Analyze – This lifecycle stage concerns the actions performed on generated or externally acquired research data to yield processed research data, ...
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[PDF] Blowfly Introduction - NIH
Blowflies lay eggs on dead animals, and their larvae feed on the body. Forensic entomologists use this to estimate time of death.
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Forensic Entomology - ENT 425 - NC State University
Forensic entomology uses blow fly larvae to estimate time since death, identify wounds, and detect toxins, using their growth as a biological stopwatch.Missing: cycles | Show results with:cycles