Differential interference contrast (DIC) light micrograph of scavenging Paramecium sp. ciliate protozoa. Paramecium are heterotrophs, which means they obtain their energy by consuming other organisms or organic matter. They are single-celled organisms found in freshwater and marine environments, as well as in soil and other moist habitats. Paramecia are characterised by their distinctive shape, which is elongated and flattened, with a tapered posterior end and a more rounded anterior end. They also possess cilia, which are hair-like structures used for movement and feeding. Scavenging paramecia feed on a variety of organic matter, including bacteria, algae, and other microorganisms. They are particularly efficient at removing bacteria from the water column, which can help to regulate microbial populations and prevent the accumulation of organic matter in aquatic environments. In addition to their ecological role as scavengers, paramecia are also important model organisms for scientific research. They have been used to study various cellular processes, such as motility, gene expression, and cell division. They are also used in toxicity testing, as they are sensitive to pollutants and can serve as indicators of water quality.