NEET Practice Questions (MCQs) with Answers & Solutions

The context describes logistic growth as: '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.'

The context explicitly defines K as 'K = Carrying capacity'.

The 'r' value is the 'intrinsic rate of natural increase'. A higher 'r' value indicates a greater potential for population growth. Since 0.12 (flour beetle) is greater than 0.015 (Norway rat), flour beetles have a higher intrinsic rate of natural increase.

The context states: 'Where $N_t$ = Population density after time t, $N_0$ = Population density at time zero, r = intrinsic rate of natural increase, e = the base of natural logarithms (2.71828)'.

The context states: '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 (Figure 11.3)'.

In the logistic growth equation, $dN/dt = rN((K-N)/K)$, when $N = K$, then $(K-N)$ becomes 0, making the entire expression for $dN/dt$ equal to 0. The context also mentions the asymptote 'when the population density reaches the carrying capacity'.

The context states: 'Any species growing exponentially under unlimited resource conditions can reach enormous population densities in a short time.'

The context explicitly states: 'The following is an anecdote popularly narrated to demonstrate dramatically how fast a huge population could build up when growing exponentially.'

The context states: 'No population of any species in nature has at its disposal unlimited resources to permit exponential growth. This leads to competition between individuals for limited resources.' This scarcity of resources is what drives the shift to logistic growth.

If N is very small compared to K, then $(K-N)/K$ is approximately equal to $K/K = 1$. In this scenario, the logistic growth equation $dN/dt = rN((K-N)/K)$ simplifies to approximately $dN/dt = rN$, which is the equation for exponential growth. Thus, the growth rate is nearly exponential.