Practice question

“High extinction and low immigration” for islands located far from the mainland usually show. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Larger islands usually support more habitats and larger populations, lowering extinction risk; less isolated islands receive colonists more readily and may experience rescue effects. These mechanisms also apply to habitat fragments that function as ecological islands. The remaining alternatives—“Low extinction and low immigration”, “High immigration and high extinction”, “Low extinction and high immigration”—refer to different states, processes, or scales and therefore do not express the same causal relationship. At equilibrium, species identities can continue to turn over even when richness is approximately stable. The model predicts a balance of rates, not an absence of colonization or extinction. The cited framing is therefore most useful when treated as a conditional biological claim, with assumptions about scale and environmental context kept explicit.