Jelly_Fish

Jelly Fish Jellyfish Few marine creatures are as mysterious and intimidating as the Jellyfish. Though jellyfish are easily recognized, the jellyfish is often misunderstood. Jellyfish belong to the phylum Cnidarians. Sea anemones, sea whips, and corals are also a part of the group. Cnidarians has three major classes, which are Hydrozoa, Scyphozoan, and Athoza. Hydrozoa are primitive fern-like creatures. The Hydrozoa group also produces small jellyfish. The Scyphozoans are adult jellyfish, or medusa. The Scyphozoans are the most common jellyfish. The last group is the Anthozoa which are the sea anemones. Jellyfish are believed to have arisen in the late Precambrian period. During the Precambrian period earth formed, the first tectonic plates arose and began to move, eukaryotic cells evolved, the atmosphere became rich in oxygen, and the first animals evolved. Even though the life of the late Precambrian period is poorly represented by fossils, a few invertebrates including creatures resembling jellyfish and worms have been discovered. A jellyfish is an invertebrate made up of ninety five to ninety seven percent water, three percent protein, and one percent minerals. The shape and size of the jellyfish varies, but most are bell jellyfish, called, bell, stomach, one, layer, epidermis, statocysts, sea, rhopalia, precambrian, period, percent, nerve, jellyfish’s, hydrozoa, group, gastrodermis, first, creatures, coelenterons, center, body, three, though, system, small, size, side, sensory, scyphozoans, range, primitive, organ, ocelli