Download
1 / 7
E N D
Characteristics: adult body form is the polyppolyps attached to sea floor with mouth and tentacles oriented upwardstubular gullet from mouth deep into coelentronsome solitary most colonialmesenteries (fleshy partitions) grow inward from body wall and are reinforced by mineralized wall or septa
Nematocysts: individual cells usually on the outer surface of the organism which have a variety of functions, most usually in defense or capture of prey species. These cells are known as stinging cells sometimes used to inject toxins which in some cases are toxic to man. Radial symmetry: Cnidarians are radially symmetrical. This means that their gastro vascular cavity, tentacles, and mouth are aligned such that if you were to draw an imaginary line through the center of their body, from the top of their tentacles through the base of their body, you could then turn the animal about that axis and it would look roughly the same at each angle in the turn. Another way to look at this is that cnidarians are cylindrical and have a top and bottom but no left or right side.
Some jellyfish are bigger than a human and others are as small as a pinhead! People in some countries eat jellyfish! Jellyfish have been on Earth for millions of years, even before dinosaurs! jellyfish have no brain but some kinds have eyes! jellyfish are mainly made up of water and protein! A group of jellyfish is called a smack! Most jellyfish live less than one year, and some some of the smallest may live only a few days.The most familiar stage is the medusa stage, where the jelly usually swims around and has tentacles hanging down. Male and female medusae reproduce and form thousands of very small larvae called planulae. The larvae then settle on the bottom of the ocean on rocks and oyster shells and form a small polyp that looks just like a tiny sea anemone. Each polyp will bud off many baby jellyfish called ephyrae that grow very quickly into adult medusae.
Some jellyfish have millions of very small stinging cells in their tentacles called nematocysts. These cells are used to capture food by injecting toxin into the prey. When we are stung it hurts because the toxin goes through our skinJellyfish are very important animals in the ocean. We should definitely respect and not harm them. They are food for a number of marine animals such as large fish and turtles. Even humans eat jellyfish! Jellyfish also provide habitat for many juvenile fishes in areas where there are not many places to hide. They can also protect the small fish from being eaten by predators with their stinging cells. Also, many young crabs hitchhike on the top of jellyfish so they don’t have to swim.
Jellyfish feel no pain so if you see one lying on the beach just leave it alone.
