Presentation on theme: "JELLYFISH By: Mayra & Allen. Jellyfish are members of the phylum Cnidaria, a structurally simple marine group of both fixed and mobile animals: sea anemones,"— Presentation transcript:
Jellyfish are members of the phylum Cnidaria, a structurally simple marine group of both fixed and mobile animals: sea anemones, sea whips, corals and hydroids are polyps that grow attached to rocks or other hard surfaces; jellyfish and colonial siphonophores like the Portuguese man-of-war are mobile (either actively swimming or subject to winds and currents). Inherent to both types of life history is their radial symmetry (body parts radiating from a central axis). This symmetry allows jellyfish to detect and respond to food or danger from any direction. Instead of a brain, jellyfish possess an elementary nervous system, or nerve net, which consists of receptors capable of detecting light, odor and other stimuli and coordinating appropriate responses. Jellyfish come in a wide variety of sizes, shapes and colors. Most are semi- transparent or glassy and bell-shaped, measuring less than an inch to more than a foot across the bell, although some may reach seven feet in diameter. The tentacles of some jellyfish can reach lengths greater than 100 feet. Regardless of their size or shape, most jellyfish are very fragile, often containing less than 5% solid organic matter.
Jellyfish are carnivorous, feeding mostly on a variety of zooplankton, comb jellies and occasionally other jellyfish. Larger species, however, are capable of capturing and devouring large crustaceans and other marine organisms. They are passive drifters that feed on passing small fish and zooplankton that become caught in their tentacles. Although primarily drifters, jellyfish are predators. They are able to stun and kill their prey with stinging cells called nematocysts.
Many jellyfish live in oceans around the world and are capable of withstanding a large flux of temperature and salinities but are most commonly found in warm, shallow coastal waters. However, some live in depths of over 12,000 feet. Jellyfish live in oceans and seas of all around the world, in shallow or deep waters and in some rivers and lakes too.
Jellyfish fact: Jellyfish has been around for more than 650 million years which means that they outdate the dinosaurs and the sharks. Jellyfish fact: Different species of jellyfish can be found in all the worlds’ ocean. Jellyfish can even be found in freshwater. Jellyfish fact: A species of jellyfish, the Box jellyfish (sea wasp) kills more people than any other marine creature. Jellyfish fact: The worlds largest known jellyfish can reach a diameter of 2.5 m/ 8ft and their tentacles can grow to be half the length of a football field. Jellyfish fact: Jellyfishes uses jet propulsion to make their way through to oceans of the world. Some jellyfish is avid swimmers while other mostly drifts with the currents. Jellyfish fact: Some species of jellyfish contains a lot of protein and is thought to be able to play a large role in ending hunger and malnutrition in poor areas around the world. Jellyfish fact: Jellyfish is able to reproduce both sexually and asexually during different parts of their lifecycles Jellyfish fact: what enables them to survive is their stinging tentacles that protects them from being preyed on.
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