[Campbell Biology P.1249] According to the logistic growth model described, when the populati... | Practice Question

According to the logistic growth model described, when the population size N exceeds the carrying capacity K , which of the following statements about the population growth rate is true?

  • A: It remains positive but slows down.
  • B: It becomes negative, indicating population decline.
  • C: It becomes zero, as the population has reached its maximum.
  • D: It increases rapidly until N returns to K.

Explanation

In the logistic growth model, the term K-N /K determines the per capita growth rate. When the population size N exceeds the carrying capacity K , K-N becomes a negative value. This results in a negative overall population growth rate, meaning the population will decline until it reaches or falls below K. The text states, 'the per capita rate of population increase approaches zero as the population size N approaches the carrying capacity K . Under some conditions... N may briefly exceed K.' This implies that when N > K, the growth rate would be negative.