Practice question

The keyed exception is “b1 and b2 are both density-dependent.” In the context of which of the following statements is false about species birth/death rates, that statement differs from the governing ecological pattern and must be evaluated against the mechanism rather than accepted from wording alone. Mechanistic support comes from showing how resource limitation, enemies, mate availability, or physiological stress changes demographic performance. A descriptive association alone does not establish regulation or causation. The remaining alternatives—“b1 is density-independent”, “b2 is density-dependent”, “d1 and d2 are density-dependent”—refer to different states, processes, or scales and therefore do not express the same causal relationship. Population ecology links individual births, deaths, immigration, and emigration to changes in abundance. Per-capita rates determine the direction of change, while density dependence creates feedback when crowding alters survival or reproduction. The cited framing is therefore most useful when treated as a conditional biological claim, with assumptions about scale and environmental context kept explicit.