Which equation depicts Verhulst-Pearl logistic population growth?
The population growing in a habitat with limited resources will show: A. Lag phase, followed by phases of acceleration and deceleration and finally an asymptote. B. The ability to realise its innate potential to grow in number and reach enormous densities in a short time. C. Exponential growth D. Logistic growth Choose the correct answer from the options given below:
Match List-I with List-II: (NEET 2023) List-I (Population Term) A. Logistic growth B. Exponential growth C. Expanding age pyramid D. Stable age pyramid List-II I. Unlimited resource availability condition II. Limited resource availability condition III. % individuals: Pre > Reproductive > Post IV. % individuals: Pre ≈ Reproductive
Asymptote in a logistic growth curve is obtained when: (NEET 2017)
Correct answer: B — dN/dt = rN(K-N)/K
The Verhulst-Pearl logistic growth equation is dN/dt = rN(K-N)/K, where K is the carrying capacity, r is intrinsic rate of natural increase, and N is population density.
A population growing in a habitat with limited resources show initially a lag phase, followed by phases of acceleration and deceleration and finally an asymptote, when the population density reaches the carrying capacity. A plot of N in relation to time (t) results in a sigmoid curve. This type of population growth is called Verhulst-Pearl Logistic Growth and is described by the following equation:
When resources are limited, populations cannot grow exponentially indefinitely. Verhulst and Pearl described logistic growth with the equation dN/dt = rN(K-N)/K, where N = population size, r = intrinsic growth rate, K = carrying capacity. This produces a characteristic S-shaped (sigmoid) curve with four phases: (1) lag phase — slow start as population is small, (2) acceleration — rapid growth as N is still much smaller than K, (3) deceleration — growth slows as resources diminish, and (4) asymptote — when N equals K, dN/dt = 0 and growth stops. The sigmoid curve is the defining feature of logistic growth and contrasts with the J-shaped curve of exponential growth.
NCERT gives the equation but NTA tests your ability to identify it from wrong alternatives. The critical term is (K-N)/K — this is the fraction of carrying capacity still available. When N approaches K, this term approaches zero, slowing growth to a halt. The wrong options in NEET use (K+N)/K or (K-N)/N — memorise that the denominator must be K (not N), and the numerator must be (K-N) not (K+N). The asymptote at K=N is where dN/dt = 0, which is the mathematical definition of the asymptote condition.
dN/dt = rN(K+N)/K — students confuse the + and - sign, or place N in the denominator instead of K.
dN/dt = rN(K-N)/K — always (K-N) in numerator and K in denominator. When N=K, growth = 0.
K-N over K: as N fills K, the fraction SHRINKS to zero — growth stops at K=N (asymptote)
Match List-I (Population Growth Term) with List-II (Correct Description): List-I A. Logistic growth asymptote B. r-value approaches zero C. dN/dt = rN D. (K-N)/K approaches zero List-II I. Exponential growth equation II. Occurs when N = K III. Population growth slowing but not zero IV. Population is near carrying capacity
Correct answer: A — A-II, B-III, C-I, D-IV
A-II: Asymptote occurs when N=K (dN/dt=0). B-III: When r approaches zero, growth slows but doesn't necessarily equal K=N (distinguishes from asymptote). C-I: dN/dt = rN is the exponential growth equation (no K term). D-IV: (K-N)/K approaches zero when N approaches K — meaning population is near carrying capacity. This tests precise understanding of all logistic growth terms.
MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.