page_title: Annual vs. perennial plant evolution
section_title: Semelparity
hierarchical_section_title: Annual vs. perennial plant evolution / Associated traits / Typical annual-associated traits / Semelparity
caption_attribution_description: Français&#160;: Modèle d’optimisation consistant à maximiser les bénéfices chez les semelpars et itéropares
context_page_description: Annuality and perenniality represent major life history strategies within plant lineages. These traits can shift from one to another over both macroevolutionary and microevolutionary timescales. While perenniality and annuality are often described as discrete either-or traits, they often occur in a continuous spectrum. The complex history of switches between annual and perennial habit involve both natural and artificial causes, and studies of this fluctuation have importance to sustainable agriculture.
  According to some studies, either the trait of annuality or perenniality may be ancestral. This contradicts the commonly held belief that annuality is a derived trait from an ancestral perennial life form, as is suggested by a regarded plant population biology text.
context_section_description: All annual plants are considered semelparous (a.k.a., monocarpy or big-bang reproduction), i.e., they reproduce once before death. Even semelparity exerts some plasticity in terms of seed-production timing over the year (see "Anomalies" section). That is, it is uncommon for all offspring to be generated at exactly the same time, which would be considered the extreme end of semelparity. Instead offspring are usually generated in discrete packages (as a sort of micro-iteroparous strategy), and the temporal spacing of these reproductive events varies by organism. This is attributed to phenotypic plasticity.
  Biennial plants (living two years and reproducing in the second) are also considered semelparous.
caption: Semelparous vs. iteroparous reproductive strategies.
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