Carnivores obtain food by killing and eating other animals and require many calories, so individual carnivores must eat many other animals over the course of a year. Herbivores only eat plants and have specialized digestive systems to digest various plant materials. Omnivores eat both plants and other animals or animal products like eggs. A food chain shows a single path of energy transfer between organisms in an ecosystem from producers to primary, secondary, and tertiary consumers. A food web depicts the complex network of interconnected food chains in an ecosystem.