Attached are the models (and output interfaces) from some of the chapters in the book by Hannon and Ruth.
Hannon, B & Ruth, M 1997 "Modelling dynamic biological systems" (Springer, New York)
Chapter 2 has some simple population growth models
Chapter 3 has some stochastic population growth models where death rate is a random variable
Chapter 4 has some population models with time lags that show chaotic behaviour
Chapter 7 has a model for a catalyzed reaction, which could describe enzyme dynamics.