Practice question

High fecundity is characteristic of many r-selected species that dominate early succession. Disturbed habitats are open, temporary, and unpredictable, so natural selection favours organisms that reproduce quickly and produce many offspring capable of reaching new patches. Seeds or propagules are often small, dispersive, and short-generation, allowing rapid population increase when light and nutrients are abundant. Investment in numerous offspring usually trades off against large body size, prolonged parental care, durable tissues, and late reproduction. Long life span and slow maturation are more often associated with species in stable, competitive later stages, although real organisms fall along continua rather than into two fixed categories. Early colonists also tend to grow fast and tolerate physical stress but may be poor competitors under shade. The “r” refers to the intrinsic rate of population increase in population models. Producing many offspring raises that potential rate, explaining mechanistically why high fecundity fits the opportunities and risks of newly disturbed successional environments.