In the exponential growth equation, if b−d is represented by r, then ‘r’ is referred to as:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → intrinsic rate of natural increase
When resources are unlimited, a population grows exponentially. If b is the per capita birth rate and d the per capita death rate, the change in population size N per unit time is dN/dt = (b − d) × N. Writing (b − d) as r gives dN/dt = rN. Here r is the intrinsic rate of natural increase. It is used to judge how any biotic or abiotic factor affects population growth, and exponential growth gives a J-shaped curve.
NCERT Extract:
Population Growth – “… The r in this equation is called the ‘intrinsic rate of natural increase’ and is a very important parameter chosen for assessing impacts of any biotic or abiotic factor on population growth.”