3.5E: Linear Dynamical Systems Exercises

Exercise \(\PageIndex{1}\)

Referring to the model in Example 3.5.1, determine if the population stabilizes, becomes extinct, or becomes large in each case. Denote the adult and juvenile survival rates as \(A\) and \(J\), and the reproduction rate as \(R\).

\[\def\arraystretch{1.5} \begin{array}{c|ccccc} & R & & A & & J \\ a. & 2 & & \frac{1}{2} & &\frac{1}{2}\\ b. & 3 & &\frac{1}{4} & &\frac{1}{4}\\ c. & 2 & &\frac{1}{4} & &\frac{1}{3}\\ d. & 3 & &\frac{3}{5} & &\frac{1}{5} \end{array} \nonumber \]

Answer

1. \(\lambda_{1} = 1\), stabilizes.
2. \(\lambda_1 = \frac{1}{24} (3+\sqrt{69}) = 1.13\), diverges.

Exercise \(\PageIndex{2}\)

In the model of Example 3.5.1, does the final outcome depend on the initial population of adult and juvenile females? Support your answer.

Exercise \(\PageIndex{3}\)

In Example 3.5.1, keep the same reproduction rate of 2 and the same adult survival rate of \(\frac{1}{2}\), but suppose that the juvenile survival rate is \(\rho\). Determine which values of \(\rho\) cause the population to become extinct or to become large.

Exercise \(\PageIndex{4}\)

In Example 3.5.1, let the juvenile survival rate be \(\frac{2}{5}\) and let the reproduction rate be 2. What values of the adult survival rate \(\alpha\) will ensure that the population stabilizes?

Answer

Extinct if \(\alpha < \frac{1}{5}\), stable if \(\alpha = \frac{1}{5}\), diverges if \(\alpha > \frac{1}{5}\).