Practice question

Semelparity means concentrating reproduction into one episode, usually followed by death, whereas iteroparity means reproducing on two or more occasions. These are contrasting life-history schedules. An annual organism need not be semelparous in the broader sense, and fecundity measures offspring production rather than the number of reproductive episodes, so neither term is the conceptual opposite. Life-history traits should be interpreted as correlated tendencies rather than rigid packages. Adult survival, juvenile mortality, body size, development time, fecundity, and parental investment interact. The central reasoning is evolutionary allocation: selection favors the schedule that maximizes lifetime reproductive success within a particular environment, even when that schedule reduces survival or reproduction at another stage. This reasoning also explains why field observations may be approximate even when the underlying textbook classification is useful. This interpretation connects individual-level processes with measurable changes in survival, reproduction, recruitment, or abundance across the population. Field evidence should therefore be compared with the model assumptions before extending the conclusion to every species, habitat, or time period.