Educational Model: Exponential Growth

This model is a component of the IUMC (Innovative Educational and Methodological Complex) "Ecology: Constructing the Biosphere", developed in 2008 by D. A. Shabanov, A. G. Kozlenko, and M. A. Kravchenko by order of the NTFP (National Training Foundation) of the Russian Federation (more about this project is in the article "Innovation and Reality"; reasons why this complex is not used are briefly described in the column "Textbooks: Straight into the Day After Tomorrow"). This model is posted here for educational use. The model demonstrates patterns of exponential population growth. The theoretical material related to the model is in the section "Exponential and Logistic Population Growth" of the manual "Ecology: Biology of Interactions". The exponential-growth model is described by the law dN/dt = r×N, where dN/dt is change in population size per unit time, N is the number of individuals of the species, and r is the reproduction (increase) coefficient. By changing controllable parameters, one can study their influence on population dynamics under unrestricted growth, and also examine effects of disturbance — sudden decline or surge in model population size. Instructions for working with the model are located at the bottom of the window; if they do not fit in the box, they can be scrolled with the arrows on the right. Some tasks that can be solved while working with the model: 1. Examine the influence of each parameter on dynamics of individual abundance in the model population. 2. In which natural or laboratory cases can reproduction following this law be observed? Which terrestrial organisms may be characterized by periodic sharp declines and exponential growth between them?