In Chapter 2 we look at the ecological relationships in the biosphere. From ecosystems and the energy flow within them to populations and how environment affects them. Limiting factors both density-dependent and density-independent factors are addressed. This product uses the interactive capabilities of a computer. The chapter has embedded an end of chapter quiz, uses graphics, animations or user interactivity on almost all pages. This product is designed to provide bite-sized pieces of information in an effort to enhance the scientific literacy of our next generation, not to overwhelm them with sheer quantity of information. Chapter 2 sections: Ecosystems • Biomes • Energy Flow within Ecosystems • Levels of Organization • Individuals vs. Populations • Factors Affecting Population Size • Concept of Population Growth Rates • The Environment and Populations • Population Density • Density-Dependent Limiting Factors • Density-Independent Limiting Factors • Homeostasis • The Role of Humans • Checking Your Understanding. This product works both on a Macintosh or PC computer.