Evolution of Swimming
Swimming evolved a number of times in unrelated lineages, and the evolutionary pressures leading to its adoption are unknown. 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 arthropods, and include the Anomalocaridids, which swam by means of lateral lobes in a fashion reminiscent of today's cuttlefish. Cephalopods joined the ranks of the nekton in the late Cambrian, and chordates were probably swimming from the Early Cambrian. Many terrestrial animals retain some capacity to swim, however some have returned to the water and developed the capacities for aquatic locomotion.
Read more about this topic: Aquatic Locomotion
Famous quotes containing the words evolution and/or swimming:
“The evolution of a highly destined society must be moral; it must run in the grooves of the celestial wheels.”
—Ralph Waldo Emerson (1803–1882)
“Whenever parents become overly invested in a particular skill or accomplishment, a child’s fear of failure multiplies. This is why some children refuse to get into the pool for a swimming lesson, or turn their back on Daddy’s favorite sport.”
—Cathy Rindner Tempelsman (20th century)