The purpose of module is to provide the sense of ecology which is a study of interactions among organisms and their environment. The effects of environmental factors depend on the abundance of plants and the interactions among and between plants and other organisms. Moreover, the pressure of the environment and of organisms upon each other is potent forces, which lead to new species and the continuing evolution of larger groups. The module covers the diversity, distribution, amount (biomass), and number (population) of particular organisms; as well as cooperation and competition between organisms, both within and among ecosystems.