Biology Project Jellyfis h Josey So (3131) My Organism Portfolio

Introduction In this project, I will talk about the features about jellyfish: feeding, respiration, excretion, movement, growth, sensitivity and reproduction.feeding respirationexcretionmovement growthsensitivityreproduction Besides, there are others information and summary.others informationsummary

Feeding  Jellyfish feed on small plankton type animals that they capture within their tentacles, which have stinging cells, called nematocysts.  Jellyfish eat small animals such as shrimp and plankton.  Some of the animals jellyfish eat are microscopic, too small to be seen by the human eye.  They also eat other jellyfish of other species.

Respiration  Jellyfish have no lungs or no gills or any special breathing organs.  The walls of the body and tentacles are so thin that the oxygen molecules are able to pass directly from the water into the internal organs and the carbon dioxide molecules pass out of the body in the same wag.  Thus, one might say that a Jellyfish breathes with it's entire body.

Excretion  Jellyfish don't produce bulky waste products, and those which they do produce are passed out through their large mouth.  Floating animals like the Jellyfish cannot afford to carry heavy items of food in their stomach while digestion takes place, because this would increase their weight, making it more difficult to stay afloat.  Therefore, the Jellyfish digest their food and get rid of the waste matter very rapidly.

Movement  Jellyfish usually drift, but occasionally you will see them swimming.  Jellyfish swim by rhythmic pulsations of the umbrella or bell.  The movement is very like an umbrella being open and shut slowly.  It is coordinated by a very simple nervous system and by sense organs around the edge that are sensitive to light and gravity and chemicals in the water.

Growth  Adult jellyfish sexually produce eggs and sperm and the larvae is, either 'brooded' within the gut of the adult or develops as a free swimming planula.  The planula settles onto a substrate, the hydratuba stage, and develops into an adult, or scyphistoma.  The scyphistoma, which is a sessile or stationary polyp, asexually buds off a small medusa which develops into an adult.

Sensitivity  Unlike more complex animals, the senses of jellyfish are limited.  Sea jellies have touch receptors on their tentacles and around their mouths to help capture food. These touch receptors may also detect vibrations in the water caused by the movement of a fish, crab, or other animal swimming by.  Sea jellies do not have a nose or tongue. They have special cells that smell and taste scattered all over their bodies.  Sea jellies do not have eyes like human eyes, but many have light- sensitive organs around the margins of their bodies.  In most cases, these organs do not detect shapes or movement, but allow the jelly to tell light from dark. Jellies can tell up from down by sensing the sunlight at the surface of the ocean.

Reproduction  Individual Jellyfish are either male or female.  The eggs and sperm develop in special areas called Gonads inside the body wall. When all of the eggs and sperm are fully developed, they are released into the stomach and then through the mouth into the sea.  As in all many-celled animals, the microscopic fertilized eggs begin a series of cell divisions which finally result in an embryo.  However, the embryo does not develop directly into a baby jellyfish, but becomes a tiny, flattened creature called a Planula.  The tiny Planula then makes its way toward the sea bottom where it actively looks for a suitable place to attach itself.

Others information  Jellyfish, or Sea Jellies, are made up of 99% water, and are found all over the world and in all the seas, even in some freshwater locations.  Most Jellyfish have very short lifespan and may live for only a few weeks, or at the most a couple of years.  Although a few types of jellyfish may present some danger to people, most are harmless.

Summary Now, we know some data about jellyfish. As the jellyfish are beautiful, we should protect them. By the way, we should protect and save the other wildlife too. That’s all of my project.