Educational Model: Interaction of Factors (Controlling Photosynthesis in a Greenhouse)

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 of an isolated greenhouse located on a spacecraft allows one, through experimentation and analysis of the resulting graph, to determine the nature of the joint influence of two factors (temperature and illumination) on organisms and to optimize energy expenditures for providing them. The theoretical material related to the model is presented in the section "Interaction of Factors" and Hutchinson's niche in the manual "Ecology: Biology of Interactions." To close the task window and proceed, click the "Next" button. 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. When selecting an operating regime for the greenhouse, use the sliders on the right side of the screen to change the amount of energy spent on plant lighting and greenhouse heating. Pressing the "Select" button shows the amount of energy accumulated during photosynthesis and its efficiency. Photosynthesis efficiency is calculated as total energy costs divided by accumulated energy and expressed as a percentage: Photosynthesis efficiency = (heating costs + lighting costs / accumulated energy)×100% The obtained results are automatically placed in a table. At the end of the work, the model determines the best value among those selected by the user. Some tasks that can be solved while working with the model: 1. Choose lighting and heating costs for the greenhouse so that plants can store, in the energy of organic matter, the highest proportion of the energy you spent (in percent). You have 4 attempts to choose optimal parameters. 2. Analyze the graph shown on the left side of the screen (it appears during the last attempt). Suggest why the highest photosynthetic productivity is characteristic of only a narrow range of temperature and illumination values. 3. Determine when the highest photosynthesis efficiency is achieved: at high or low productivity?