Question

Fastest phase of S-shaped growth curve is
A. Lag Phase
B. Log Phase
C. Stationary Phase
D. Both (A) and (B)

Answer 1

Hint: The conditions are ideal in the phase where there is rapid growth and the maximum growth is reached. The S-shaped logistic growth curve has 3 phases: Lag phase, Log phase and Stationary phase.

Complete answer:
First of all, you should know that the S-shaped growth curve is a pattern of S- shaped growth curve where in a new environment the population of organisms increases slowly in the starting and then it increases rapidly by approaching the exponential growth rate as the J-shaped curve. But then it declines or you can say it slows down due to the factors such as food ,water and limited space. S-shaped growth curves include three phases which are Lag phase, Log phase and Stationary phase.

- Lag Phase: It is that phase when organisms are introduced into a new environment then the population growth starts slowly.
- Log Phase: It is that phase where there is rapid growth and the maximum growth is reached in this phase. The conditions are ideal in this.
- Stationary Phase: In this phase, the growth rate starts to slow down due to factors such as food, water and limited space.

> If we look at option A which is the Lag phase, there is a slow start of the growth so this cannot be the fastest phase of the S-shaped growth phase.

> Moving to option B which is Log phase, in this phase conditions are ideal and there is rapid growth and also maximum growth is reached as per the explanation given above. So, this phase is the fastest phase of the S-shaped growth curve.

> Option C is the Stationary phase where the growth starts to slow down and due to it this cannot be the fastest phase. Therefore, this option is incorrect.

> Option D is Both A and B but this cannot be the right one because in the lag phase there is no rapid growth, it is seen only in the log phase. Therefore, this option is incorrect.

Hence, the correct answer is option (B).

Note: The slope of curve shows clearly that the log phase is the fastest and it is a sigmoid shaped curve where the slow growth starts which leads to the rapid growth and the maximum growth is reached. That phase is the fastest one and that is the Log Phase.