The purpose of this study is to develop an economic growth model to explain dynamic interactions among physical capital accumulation, population adjustment, and human capital improvement. We assume that human capital can be increased by education and learning by doing. Population growth may be affected by knowledge and economic conditions. We examine the effects of changes on some parameters by traditional comparative static analysis under presumed stability. We also guarantee the existence of permanent oscillations when the system loses its stability due to shifts in the population adjustment speed parameter.