Jellyfish
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JELLYFISH By: Emily
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Transcript of Jellyfish
JELLYFISHBy: Emily
WHAT ARE THEY?
Jellyfish or jellies are the major non-polyp form of individuals of the phylum Cnidaria.
They are classified as free-swimming marine animals consisting of a gelatinous umbrella-shaped bell and trailing tentacles.
The bell can pulsate for locomotion, while stinging tentacles can be used to capture prey.
WHAT DO THEY EAT?
Jellyfish normally eats whatever their long tentacles catch while drifting in the ocean currents. A few species of jellyfish like the box jellyfish are good swimmers and chase their prey. The main food sources of jellyfish are smaller fishes, eggs and larvae of sea creatures and zooplankton. The larger species of jellyfish eat crustaceans and other jellyfish.
FACTS
The same opening under the body that serves as its mouth is used for releasing excreta from the body. The food entering the opening is digested in the cavity attached to it. The waste matter generated is expelled through the same opening.
Jellyfish is carnivorous and ravenous eaters. The mouth of the jellyfish is located underneath the bell-shaped body. Its simple digestive system consists of a gastro vascular cavity attached to the oral opening, which does the function of the stomach.
The tentacles are the main devices to catch prey for jellyfish. These tentacles have thousands of cnidocytes with stinging capsules or nematocysts containing venom. Even though these creatures are brainless, their nervous system is highly developed. When the tentacles touch a potential prey, the cnidocytes are activated immediately. They shoot nematocysts at the prey, which attach itself to the skin of the prey. The venom present in these nematocysts is released, which in turn stuns the prey.
The shocked prey is caught by the arms surrounding the oral opening and brought to the mouth. The food is digested immediately in the chamber attached to the opening and nutrients absorbed by the body. The waste is discharged through the same opening.
Many species of jellyfish are passive hunters and wait for their prey to come to them. They have sticky tentacles and drift along the currents waiting for a prey to get trapped in the tentacles. They eat mostly zooplankton, eggs and larvae of other marine creatures and crustaceans.
Some species of jellyfish are aggressive hunters and they are equipped with potent venom in their tentacles. This venom when ingested in the prey either paralyzes or kills it. This group of jellyfish preys on smaller fishes, crustaceans and even other jellyfishes. Some jellyfish is known to eat other jellies as large as themselves.
THE END
