2.I.6B

Mathematical Biology
Part II, 2008

The population dynamics of a species is governed by the discrete model

Nt+1=f(Nt)=Ntexp[r(1NtK)]N_{t+1}=f\left(N_{t}\right)=N_{t} \exp \left[r\left(1-\frac{N_{t}}{K}\right)\right]

where rr and KK are positive constants.

Determine the steady states and their eigenvalues. Show that a period-doubling bifurcation occurs at r=2r=2.

Show graphically that the maximum possible population after t=0t=0 is

Nmax=f(K/r).N_{\max }=f(K / r) .