Trophic levels are the different stages in a food chain that represent how energy and nutrients flow through an ecosystem. They are typically divided into four main levels: producers, primary consumers, secondary consumers, and tertiary consumers. Producers, like plants, convert sunlight into energy through photosynthesis, while primary consumers, such as herbivores, eat these plants. Secondary consumers, often carnivores or omnivores, feed on primary consumers, and tertiary consumers are at the top of the food chain, preying on secondary consumers. Each level relies on the one below it for energy, illustrating the interconnectedness of life in an ecosystem.