2. Terms for trophic levels: autotroph, heterotroph, producer, consumer (1¡, 2 ¡, 3¡), herbivore, omnivore, carnivore.
3. Pyramid of energy -- measured in different ways depending on what information is needed: numbers, biomass.
4. Trophic level for each level of the pyramid and only a small fraction of the energy is passed from one level to the next.
5. Food chains and food web: many interactions with organisms depending on one another for survival of the ecosystem; disappearance of critical organisms can crash the system. Toxins are accumulated and amplified as the trophic levels increase.
6. Food webs as they relate to humans: enough grain is produced each year to feed the world's population, but millions of people are starving. Ten times as many people could be fed if everyone in the world was a vegetarian.