In large part, paleoecology depends on comparisons of ancient organisms with living organisms. We use modern analogs to help us interpret something about the way in which the fossils lived and related to their environment. Some organisms live on the land, and some live in the water. Includes rivers, freshwater lakes, springs, caves, wells, groundwater. Hypersaline - water of very high salinity, such as the Great Salt Lake, Dead Sea, and some tropical bays and lagoons with high evaporation rates.
Marine organisms inhabit the pelagic realm - all of the water overlying the ocean floor.
Bottom dwellers capable of movement are called vagile or vagrant . Bottom dwellers which do not move are called sessile . Consumers or heterotrophs - cannot produce their own food and must eat. Predation - one species eating another.