Practice question

Competition and predation are components of environmental resistance because they prevent a population from realizing its unrestricted biotic potential. Competitors reduce access to limiting resources, while predators remove individuals and can alter behavior or habitat use. Environmental resistance also includes disease and abiotic constraints, collectively lowering actual growth below the maximum represented by r. The logistic model is a deliberately simplified, density-regulated model. It assumes a constant intrinsic rate and carrying capacity, no time delay, and no age or spatial structure. Its value lies in exposing the feedback mathematically; real populations can oscillate, overshoot, or track a changing K when those assumptions fail. A useful check is to ask what happens at the biological extremes and whether the proposed mechanism still makes sense. Interpreting the example at the appropriate population scale keeps the causal mechanism distinct from a simple correlation or an absolute rule. Ecological predictions remain conditional on the stated environment, because changing resources, mortality, or interactions can alter the observed demographic pattern.