A model for self-reproducing resources with limited growth is obtained by choosing f sRd − rRs1 2 RyKd, tsR, Cd − bRC, and hsCd − C. Assume all constants are positive and K . ys«bd.

Consumer-resource models often have the following general form R9 − f sRd 2 tsR, Cd C9 − «tsR, Cd 2 hsCd where f sRd is a function describing the rate of replenishment of the resource, tsR, Cd describes the rate of consumption of the resource, and hsCd is the rate of loss of the consumer. The constant « is the conversion efficiency of resources into consumers and lies between zero and one. Construct the phase plane, including all nullclines, equilibria, and arrows indicating the direction of movement in the plane. Describe how consu