Wow! These are some really neat animals! Some of them can really pack a sting!
Jellyfish belong to the Phylum Cnidaria. They are invertebrates and are made up of 95% water. Jellyfish do not swim, but drift with the tides. For that reason, some people consider them to be plankton. They have no heart or brains.
Jellyfish have specialized stinging cells, called cniodocytes. Each of these cells contains a nematocyst which acts like a mini-harpoon. When a jellyfish touches something the nematocyst is released and injects toxin into the prey.
Australia's box jelly has a lethal toxin more
potent than cobra venom and can kill a person in minutes.
Portuguese man o' war stings are very painful. They can cause fever, shock and in some rare instances, cause the heart to stop beating. Never touch a jellyfish lying on the beach because the nematocyst can still sting you even though the animal is dead.
Jellyfish live in all the world's oceans.
Jellyfish are a favorite food of leatherback sea turtles.
Activities with Jellyfish
Glue long strips of different colored tissue paper to the underside of a paper plate. Color the plate with squiggle lines to resemble a jellyfish. To make a Portuguese man o' war, glue the strips to one side of the plate. Fold the plate in half and staple it closed. Color the outside.
This animal is often mistaken for a plant, but it is really a cnidarian and related to the jellyfish. We know it by the name anemone. Anemones have been described as corals that do not have skeletons.
The tips of an anemones tentacles contain stinging cells called nematocysts. These nematocysts inject poison into any prey that is within reach.
Anemones are often found on the shells of hermit crabs. The hermit crab benefits when a sea anemone is attached to its shell. The anemone provides camouflage because many predators will avoid the poisonous sting of the anemone's tentacles. The anemone benefits because it feeds on the scraps of the crab's food. This relationship is called symbiosis because it benefits both of the animals and neither of them is harmed.
clownfish also has a symbiotic relationship with the anemone. The
clownfish has a special mucous coating on its skin that protects it from the
stinging tentacles of the anemone. The clownfish finds safety within the
tentacles of the anemone, and it repays the anemone by chasing off it's
predators, such as the butterfly fish. The clownfish also eats the tiny
scraps of food that are dropped by the anemone.
There are two main types of corals. One type has skeletons and builds reefs (staghorn, brain) and are known as stony corals, the other type of corals are known as soft corals (sea fan). Corals are made up of tiny animals known as polyps. Each of the polyps has a skeleton cup, tentacles with stinging cells, a mouth and a stomach. Algae grow in the stomach lining and supply calcium which the polyp uses to build the skeleton cup.
Here's a neat model of a coral polyp your students can make. Give each child a paper towel tube. Next, give each student a toilet paper tube that will fit inside the paper towel tube. You will need to collect a lot of tubes because not all toilet paper tubes will fit inside a paper towel tube, but most will. Cut the tubes into four inch lengths. Pull a latex disposable glove through the paper towel tube so that only the fingers are showing. Using a permanent marker, make dots in the center of each finger to represent the mouth. Make colored dots along the fingers to represent the stinging cells. Put the toilet paper tube inside the paper towel tube to hold the glove in place against the sides of the paper towel tube. Make a base for the coral polyp out of self hardening clay. Paint the paper towel tube and the clay to represent the various colors of corals.
Back to Under the Sea ~ Fishy Links - Ocean Life Links ~ Teacher's Guide
Fishy Tales - Student Storybooks for Under the Sea ~ Fishy Fun
Dauphin Island Sea Lab
© 2001 S. Seagraves
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Mrs. Seagraves' QUEST Class