Question

The graph shows two types of population growth curve. $A$ is exponential and $B$ is logistic.

Which one of the following growth model considered as more realistic one?

• A. Exponential growth curve
• B. Logistic growth curve
• C. Both the growth curves
• D. None of the above

Answer 1

Answer: (B)

Growth model considered more realistic is logistic or sigmoid growth curve.
Sigmoid growth is density dependent and can be expressed by the following equation:
$\frac{dN}{dt}=rN\frac{(K-N)}{K}=rN\left(1-\frac{N}{K}\right)$
$N=$ Population size
$t=$ Intrinsic of natural increase
$K=$ Carrying capacity
$r=$ Intrinsic rate of natural increase
$\frac{K-N}{K}=$ Environmental resistance
$N=K_1$ the growth rate and becomes zero and population reaches to equilibrium.