In order to live, all organisms must eat. A food chain is a hierarchical system of consumption. There are three basic levels in the food chain of a pond.
- Producers or autotrophs: Made up of phytoplankton and plants, these organisms use sunlight and photosynthesis to create their own food.
- Herbivores: Insects, invertebrates and crustaceans which consume the plants.
- Carnivores: Fishes and other organisms which can feed on both plants and herbivores.
The decomposers, or sapotrophs, are at the very bottom of the food chain. Mostly comprised of fungi and bacteria, these organisms are vital to the nutrient cycle, as they convert all dead organic matter into carbon dioxide and nutrients that can be readily use by algae and plants to produce food.