The STRANGE L ife The (unknown to some) life of the jellyfish ~By~ Parker Respect that fact!!! Enjoy!
Introduction What are jellyfish? They are animals, of course. To some, though, it doesn t seem that way, and it s easy to understand why. Their natural yet almost non-understandable bodies seem to set them apart from all other animals. Despite all this, they are in fact entirely natural. Not only are they thriving, but they also have an effective lifestyle. This style may only seem effective to some by hearing the rest of my report, or getting information from another source. But in the meantime, you are about to hear the rest of my report. Once it s over, you will (most likely) understand their different, complicated life.
Habitat Jellyfish live in oceans all over the world. Different kinds live in different areas, which are mostly in some part of the open ocean. The largest can grow up to 6 feet wide and 117 feet long (which is just a little longer than Park s field) and is found in cold, northern waters. Other kinds live 3,300 feet beneath the sea in the middle of the Atlantic Ocean! They have been found swimming around coral reefs if they wander (or float) away from where they re normally found. They may be stranded on beaches, where they melt into a puddle of gel, if they re pushed even farther than the reef. Species have most likely adapted to where they live, and also to withstand the conditions of heat or cold in the water. Even if they ventured into an unfamiliar place, they re pretty much geared up for anything except predators. This may be a hint to how they have survived for millions of years.
Diet/Hunting All jellyfish hunt. They almost all have stingers- or nematocysts- that will fire barbed harpoons filled with poison when the sense cells on them detect movement. This is the method that most jellyfish use, although there are a few that differ. Two of the more interesting methods are used by the Moon Jelly and the Cabbage Blebs. They use methods different than the normal jelly in many ways. They may only use their stingers for protection. The Moon Jelly eats plankton, like most other smaller jellyfish do (including the Cabbage Blebs). The way it catches these impossibly small plants/ animals is by beating small hairs near its mouth very, very fast. This causes a rushing current of water to flow past its mouth. The hairs push the water into the mouth, where it is filtered to remove the edible plankton, and send out the excess water. This is a helpful method because water is always there, plankton is always in the water, and whenever it needs food, it s always there! The Cabbage Bleb s method is similar, but not exactly the same. It also eats plankton, and filters the water, like the Moon Jelly. The only difference is that it has very small tentacles around its mouth, which act like the hairs on a Moon Jelly in the same way it uses them to send water past the mouth, but theses tentacles filter the water in a way people cannot quite understand. This method is helpful in the same way as the Moon jelly s method, in a way. Aside from the jellyfish that catch smaller prey, Jellyfish that catch larger prey usually have long, semi- muscular tentacles (as long as 40 feet) to get their fish. They can reach for prey far down into the abyss, and because the tentacles are muscular they can curl them up to their mouth so they can actually eat them. Although this is only a small selection of hunting methods, only a few other jellyfish have extremely different methods as the Cabbage Bleb and Moon Jelly, but until more are discovered, it s mostly the same.
The Jelly Body Bodies. All animals have very complex bodies. On land, airbreathing animals have generally similar bodies. In the ocean, though, there are strange and unnatural bodies, especially deep-sea creatures. Most of the strangest bodies are a result of adaptation, and are actually perfect for the temperatures and other conditions that they live in. The jellyfish s body has been given millions of year to adapt to wherever that species lives. Strangely enough, without a heart, brain or self-realization, their bodies are almost perfect. Most people don t realize that the dome shaped body, for starters, is at all helpful when in fact it is. This is hard to believe because their strange dome shaped head is very irregular and different than any other creatures. Actually all jellyfish have a dome shaped body and it is vital because it is not only a mouth but also a propeller (see locomotion for how) in the sense that it moves the rest of the body forward. It is made up of two layers of skin. The first layer is covered with sense cells. These can detect light, gravity, and movement in the water. The jellyfish can sense if a predator or mate is nearby with these cells. The first layer is bound together with the other skin layer by a binding of nerves and muscles. These will help with locomotion. The mouth is in the center of the body, and the food is brought up to it with the long, muscular tentacles hanging around the center of the dome. Once the food enters the mouth the second layer of skin digests it. It is unknown how the skin acts like a stomach. These stingers can grow up to 40 feet if the species is known for that. They are made to curl up to the mouth so they can actually eat the food they catch. The food is hoisted up to the mouth of a creature with one of the strangest bodies on earth that is known so far.
Locomotion Moving around. All animals do it. Whether it s to escape from predators or find a potential mate, so do jellyfish. Although it seems impossible with their creepy body and dragging tentacles, they can. Here s how: the muscles and nerves in between the skins open and close their umbrella of a body. These muscles cannot pull it closed, but its jelly body is made out of gel, of course, and when the nerves pull it open it bounces back into its shape. This sends a jet of water to send it forward. Most jellyfish get around like this, but there are a few exceptions. The Portuguese man-ofwar is one, for instance. And truly, this creature is not a true jellyfish. It is made up of thousands of tiny polyps that stick together to make a giant bell of a body. It is pushed around by the wind like a sailboat on the water. This may seem like a strange and unhelpful maneuver, but not as weird as the Cassiopea, or upside-down jelly. All it does is crawl around on the sand on the bottom of the ocean using its muscular flat dome. It is also able to lift off the bottom by curling up its body in a sort of fan-like way. It will float to find food (plankton). The Cassiopea has a VERY un-animal-like way of moving. So does the man-of-war. They all do, or so we hope. Then they would lose what makes these fascinating things less fascinating.
Reproduction/ Life Cycle There are a lot of jellyfish. There have been for millions and millions of years. In order for them to stay, there has to be reproduction as well as a safe life cycle. And they do have one. It all starts with many different gatherings (or shoals) of jellies come up to, or closer to, the surface. Different shoals are gatherings of different species. Once all together, the males release sperm into the water. Any available female soaks it up through her mouth. Once inside her, the sperm fertilizes 1,000 s- not just one- of the eggs. They give birth to this many offspring because of the fact that predators may eat some without noticing. These eggs stay inside the female for a short while. They will hatch inside her when fully ready, then float out of the females mouth. They are now free to roam alone, and to begin their life cycle. In the first stage of growth, they stick themselves to rocks until they have grown to be big enough to swim. When they are ready, they disconnect and officially enter their polyp stage. In this stage they look like a long, swimming sea anemone. After a week in this stage, its body splits into discs called dishes. The excess dishes all become other polyps and go into the medusa stage by themselves. In the medusa stage they start to look like a small, deformed jelly. They are now hunting and swimming. Using the food, the medusae will start to change over time into real jellyfish, looking like a person normally sees them. Of course, in a jellyfish s case, normal is strangely interesting.
Predators Although jellyfish are powerful hunters and very poisonous, they are not the big fish that eats the little fish, or in other words, they are not at the top of the food chain. In fact, the leatherback turtle eats almost nothing but jellyfish, even stinging ones. Certain kinds have many predators, including the sea slug. First, it covers itself in sting-proof mucus and bites the jellyfish s stinging tentacles off! It will store them on its own back for protection. This will leave the jellyfish vulnerable to attack without any defense. They can be attacked by crabs (crabs have been seen ripping apart jellyfishes on the sea floor) or sea turtles. Different jellyfish species may have many, many predators. Certain species are even captured by humans. In China, non- stinging jellies are captured with nets and brought ashore. They are cut into strips and soaked in water for twelve hours. Once ready, they are served in salads or served alone with soy sauce and vinegar. Although jellyfish salad is a treat to some, they kill thousands of jellyfish to make it. This makes humans a dangerous predator. All of their predators are dangerous, but nonetheless jellyfish are a strategic predator too. They can still survive. Mostly.
Conclusion I hope you have learned more about jellyfish, and noticed how lively and living they are. Even though this report has a lot of facts about their strange and complicated life, there is still much more to learn. I hope you will pass this information on to other people, so they can learn more about jellyfish as well as understand them more.