Tue, Sep 29th 2009, 12:35
Jellyfish existed on earth before the dinosaurs. These fragile creatures have existed for over 650 million years and continue to thrive.
Jellyfish abound in the earth's oceans. There are over 2,000 species of jellyfish known to exist, small and large, existing in the shallows, deepest reaches of the oceans and even in fresh water.
Despite their name, jellyfish are not fish at all. They are more closely related to coral and sea anemones - belonging to the family of invertebrates called Cnidaria. Cnidaria are carnivores, distinguished by the existence of specialised cells used for capturing prey. Jellyfish are the only members of this family which are mobile.
Jellyfish do not actually swim, but rely on the ocean currents to get around. However they can move up and down in the water by ejecting water out of their bodies. Jellyfish are usually cup shaped (their scientific name is Scyphozoa, from the greek for ‘cup'). They are perfectly symmetrical so they can react to dangers in every direction. Jellyfish.