Educational Model: Ecological Factors
The model demonstrates basic patterns of the influence of one or several ecological factors on organisms.
Part 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 use in the educational process. The model demonstrates basic patterns of the influence of one or several ecological factors on organisms. The theoretical material related to the model is presented in the sections "Ecological Environment," "Difference Between Resources and Conditions," "Liebig's Law of the Minimum," and "Shelford's Principle of Tolerance" of the manual "Ecology: Biology of Interactions." The left side of the screen presents a model organism whose state depends on the selected factors and their intensity. The study object (plant, bacteria) is selected using the corresponding icons in the workspace. On the right side of the model screen there is a graph showing the dependence of organism response on the values of one or several selected factors. Values of different factors are indicated by curves of different colors. First, select one factor from the list whose effect will be studied during the work. In this case, all other factors are assumed to have optimal values. To change them, select factors No. 2 and No. 3 from the list. Note that the model does not specify units in which factor intensity is measured. This is because each factor has its own measurement units and favorable or unfavorable values for the organisms under study. Instructions for working with the model are located at the very bottom of its window; if the instructions do not fit in the window, they can be scrolled up and down with the arrows to their right. Some tasks that can be solved while working with the model: 1. Determine which of the proposed factors are resources and which are conditions. Which forms of organism-response dependence on factor value are characteristic of resources, and which of conditions. 2. Working with the model, determine (and mark in a table) whether one factor can be a condition for one organism and a resource for another. 3. Provide examples of conditions unfavorable both at low and high values, and conditions unfavorable only at extremely low or extremely high values. 4. By experimenting with an "organism" experiencing unfavorable values of two or three factors, find a simple way to determine which factor is limiting.