Swimming evolved a number of times in unrelated lineages. Supposed jellyfish fossils occur in the Ediacaran, but the first free-swimming animals appear in the Early to Middle Cambrian. These are mostly related to the See more

Among the radiata, jellyfish and their kin, the main form of swimming is to flex their cup shaped bodies. All jellyfish are free-swimming, although … See more

Most of the Amphibia have a larval state, which has inherited anguilliform motion, and a laterally compressed tail to go with it, from fish ancestors. The corresponding tetrapod adult forms, even in the tail-retaining sub-class Urodeles, are sometimes aquatic … See more

Aquatic reptiles such as sea turtles (see also turtles) and extinct species like Pliosauroids predominantly use their pectoral flippers to … See more

Microbial swimmers, sometimes called microswimmers, are microscopic entities that have the ability to move in fluid or aquatic environment. Natural microswimmers are found everywhere in the natural world as biological microorganisms, … See more

Many fish swim through water by creating undulations with their bodies or oscillating their fins. The undulations create components of forward thrust complemented by a … See more

From the point of view of aquatic propulsion, the descent of modern members of the class Reptilia from archaic tailed See more