The sequence of transfers of matter and energy from organism to organism in the form of food. food chains intertwine locally into a food web because most organisms consume more than one type of animal or plant. plants, which convert solar energy to food by photosynthesis, are the primary food source. In a predator chain, a plant-eating animal is eaten by a larger animal. In a parasite chain, a smaller organism consumes part of a larger host and may itself be parasitized by smaller organisms. In a saprophytic chain, microorganisms live on dead organic matter.