The varied diets exhibited by animals are accompanied by a variety of mechanisms used to obtain food. Suspension-feeders sift small food particles from the water. Substrate-feeders live on or in their food source and eat their way through the food. Earthworms ingest soil and their digestive systems extract the organic materials. Bulk-feeders eat relatively large pieces of food.
Ingestion is the first stage and is the act of eating.
Digestion is the second stage and is the process of breaking down food into small molecules the body can absorb.