Igcse Model Questions Vol1 2021 Biology Question 12

A population of a beetle is studied using a simple life‑table. The data are:\n\\[\n\begin{array}{c|c|c}\n\text{Age class (years)} & l_x & m_x \\ \hline\n0-1 & 1.0 & 0 \\n1-2 & 0.6 & 1.2 \\n2-3 & 0.3 & 2.5 \\n\end{array}\n\\]\nwhere \(l_x\) is the proportion surviving to the start of the age class and \(m_x\) is the average number of female offspring produced per individual in that class.\n\n(a) Calculate the net reproductive rate \(R_0\).\n(b) Calculate the generation time \(G\) using \(G = \frac{\sum x\,l_x m_x}{R_0}\), taking the midpoint of each age class as the representative age (\(x = 1.5\) for class 1‑2 and \(x = 2.5\) for class 2‑3).\n(c) Based on \(R_0\), will the population increase, decrease or remain stable?