Which graph best represents logistic population growth as it approaches carrying capacity?

Which graph best represents logistic population growth as it approaches carrying capacity?

• A. A flat line with no growth.
• B. An exponential growth curve.
• C. An alternating up-and-down curve.
• D. An S-shaped curve showing growth slowing as it approaches carrying capacity.

Answer: (D)

Population growth under limited resources follows a logistic pattern: when numbers are low, growth is rapid because resources are plentiful; as the population grows, competition for space and food increases, so birth rates slow and deaths may rise, causing the growth rate to decline. This produces a smooth S-shaped (sigmoidal) curve that starts steep and then levels off as it approaches the environment’s carrying capacity—the maximum population the ecosystem can sustain indefinitely. That’s why the best graph is the one that shows growth slowing as it nears carrying capacity. The other options either depict continuous, unchecked growth, no growth at all, or oscillations that aren’t the typical leveling-off behavior of logistic growth.

Population growth under limited resources follows a logistic pattern: when numbers are low, growth is rapid because resources are plentiful; as the population grows, competition for space and food increases, so birth rates slow and deaths may rise, causing the growth rate to decline. This produces a smooth S-shaped (sigmoidal) curve that starts steep and then levels off as it approaches the environment’s carrying capacity—the maximum population the ecosystem can sustain indefinitely.

That’s why the best graph is the one that shows growth slowing as it nears carrying capacity. The other options either depict continuous, unchecked growth, no growth at all, or oscillations that aren’t the typical leveling-off behavior of logistic growth.