Practice question

“Extinction vortex” for which concept describes positive feedbacks between biotic and abiotic factors driving extinction. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Extinction risk rises when abundance, geographic range, or genetic variation becomes small because demographic chance, environmental fluctuations, inbreeding, and rare catastrophes then have disproportionate effects. Correlated losses among subpopulations further weaken regional persistence. The remaining alternatives—“Habitat fragmentation”, “Genetic drift”, “Environmental bottleneck”—refer to different states, processes, or scales and therefore do not express the same causal relationship. The mechanism should be evaluated across both local and global scales. Local disappearance can be reversed by recolonization, whereas global extinction is irreversible and requires the loss of every surviving population. Linking the wording to measurable consequences for fitness, abundance, or flux gives the conclusion its scientific meaning and prevents a purely mnemonic interpretation.