AP Biology: Carrying Capacity and Logistic Growth Practice Questions
Practice carrying capacity and logistic growth with original AP Biology multiple-choice questions. These items connect population-growth equations and graphs to resource limits, density-dependent regulation, overshoot, and changing environments.
Free original practice questions for study purposes. Open Exam Prep is an independent study resource and is not affiliated with, endorsed by, or sponsored by the makers of AP Exams.
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Answer the questions below — you get instant feedback and a full explanation for each.
1. What does carrying capacity represent for a population in a particular environment?
Explanation. Carrying capacity, represented by K, is the population size that available resources and other environmental conditions can support over time.
2. Which graph shape is most characteristic of logistic population growth?
Explanation. Logistic growth is S-shaped. Growth is rapid when resources are abundant, then slows as population density approaches carrying capacity.
3. In the logistic growth model dN/dt = rN(1 - N/K), what happens to population growth as N approaches K?
Explanation. As N approaches K, N/K approaches 1 and the limiting factor approaches zero. The model therefore predicts little net population growth near carrying capacity.
4. A deer population grows quickly after entering a habitat, but its growth rate later slows as food becomes scarce. Which model best describes this pattern?
Explanation. Rapid early growth followed by slowing near a resource limit is the expected logistic pattern. Food scarcity contributes to environmental resistance.
5. Under the basic logistic model, at approximately what population size is absolute population growth greatest?
Explanation. The product N(1 - N/K) is largest at N = K/2, so the logistic model predicts the greatest absolute increase around half the carrying capacity.
6. Which factor is most likely to impose density-dependent limits on a crowded plant population?
Explanation. Competition generally intensifies as population density rises, making it density dependent. The listed weather and geologic disturbances are more often density independent.
7. A prolonged drought reduces the amount of vegetation available to a rabbit population. What is the most likely immediate effect on carrying capacity?
Explanation. A reduction in a limiting resource can lower K. Carrying capacity is not fixed forever; it can change when environmental conditions change.
8. How does logistic growth differ from exponential growth?
Explanation. Exponential growth assumes an effectively unlimited environment, whereas logistic growth incorporates slowing caused by limits as N approaches K.
9. A population temporarily rises above the carrying capacity of its habitat. Which outcome is most consistent with an overshoot?
Explanation. During an overshoot, the population exceeds the level that current resources can sustain. Resource depletion can then produce a dieback or oscillation.
10. Researchers observe that a yeast culture has N = K in the logistic model. If K and other conditions remain unchanged, what does the model predict for dN/dt?
Explanation. When N equals K, the term (1 - N/K) equals zero. The basic model therefore predicts no net change in population size.
11. Two populations have the same intrinsic growth rate and current size, but population A is much closer to its carrying capacity than population B. What does the logistic model predict?
Explanation. The limiting term (1 - N/K) is smaller when N is closer to K, reducing the per-capita and total growth predicted for population A.
12. A lake restoration increases nesting habitat and food for a bird population. If other conditions are similar, which prediction is most reasonable?
Explanation. Improving limiting resources can allow the environment to sustain more birds, increasing K. Population size may then grow toward the new carrying capacity.
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FAQ
What is carrying capacity in AP Biology?
Carrying capacity, K, is the population size an environment can sustain over time under its current resource and environmental conditions.
Why is logistic growth S-shaped?
Growth begins rapidly when the population is well below K, slows as density-dependent limits strengthen, and levels near carrying capacity.
Can carrying capacity change?
Yes. Changes in food, habitat, climate, disease, predators, or other limiting factors can raise or lower carrying capacity.