Elutsükli

Elutsükli is the Estonian term for life cycle. It refers to the sequence of stages that an organism or a population passes through from origin to end. The concept is used across biology, ecology, agriculture, and related disciplines to describe temporal changes, development, reproduction, and death. A life cycle may vary considerably between species, and can include metamorphosis, alternating generations, or continuous growth.

In animals, life cycles typically begin with an embryo or egg, followed by juvenile and adult stages, with reproduction producing offspring for the next generation. Some species undergo metamorphosis, such as caterpillars becoming butterflies, or tadpoles becoming frogs. In plants, life cycles are categorized as annuals, biennials, or perennials; processes include germination, vegetative growth, flowering, seed production, and dispersal, after which the cycle can recur.

Life cycles also apply to organisms that reproduce asexually, as well as to populations and ecosystems. In agriculture and medicine, understanding life cycles helps in pest management and disease control by identifying vulnerable stages. In sustainability, the term is extended to life cycle assessment (elutsükli hindamine), a framework for evaluating the environmental impacts of a product or service throughout its life span.

Variations such as alternation of generations, diapause, and senescence illustrate the diversity of life cycles. Studying elutsükli emphasizes how timing, environment, and reproductive strategy shape the persistence and propagation of organisms and systems.