Recall the general form for a single species discrete-time model is

Nt+1 = f(Nt) = N₂F(N₂)

In the last lecture we met linear population models with exponential

growth (or decay), where the net per capita growth rate was

density-independent: F(N) = X.

A nonlinear population model has a density-dependent net per

capita growth rate.

Q: Why might F(N) be density-dependent?