Part of understanding how the populations in an ecosystem interact includes examining how energy flows from the producers to consumers. These relationships are organized into diagrams called food webs. In this topic, you explored food webs, trophic levels, and the categories of organisms in food webs. You also learned about pyramid diagrams, which depict how energy, biomass, and numbers of organisms are structured in an ecosystem. Water, carbon, and nitrogen flow through ecosystems, and the cycles associated with each are important components to life on Earth.