Jellyfish Propulsion
Photos by Gary Bell © www.oceanwideimages.com
Jellyfish
are unusual creatures in the fact that they have no heart, brains, or
eyes. Being made up over 95% water, the only mechanism for
possible movement they have are the muscles located in on the underside
of their "bells". These muscles allow some jellyfish to move by
jet propulsion. Other smaller jellyfish just float along in the
water or "drift". The ones capable of propulsion still cannot
overcome the forces of the oceans current and tides so they rely
somewhat on drifting as well.
When a jellyfish moves, the muscles in the bell contract and push water out of the hollow bell. This causes an equal and opposite reaction by Newton's Th rid Law and pushes the jellyfish forward. Sacs on the bell rim keep the jellyfish balanced in the water. The sacs contract when nerve endings in them are stimulated, reorienting the jellyfish. Jellyfish have no brain or eyes so they rely on nerve cells in their bells to respond to food and dangers.
Scientist have only recently understood the movement of jellyfish, and jellies have been "jet propelling around for over 550 million years". (sciencenews.org) They are known as the first swimmers in the ancient seas before lobsters and other marine anthropoids.
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When a jellyfish moves, the muscles in the bell contract and push water out of the hollow bell. This causes an equal and opposite reaction by Newton's Th rid Law and pushes the jellyfish forward. Sacs on the bell rim keep the jellyfish balanced in the water. The sacs contract when nerve endings in them are stimulated, reorienting the jellyfish. Jellyfish have no brain or eyes so they rely on nerve cells in their bells to respond to food and dangers.
Scientist have only recently understood the movement of jellyfish, and jellies have been "jet propelling around for over 550 million years". (sciencenews.org) They are known as the first swimmers in the ancient seas before lobsters and other marine anthropoids.
Return To Main Go To Eels Fish Dolphins