Flatworms And Roundworms

Flatworms and roundworms are very interesting soft and long body organism. Find out more information.

An animal having a soft long body is called a worm. This article will define both flatworms and roundworms.

Flatworms include free-living turbellarians, parasitic flukes, and parasitic tapeworms; all have flattened bodies that are shaped like long ribbons or broad leaves. The flatworm is a good example of Planaria. A microscope is necessary for some. Some tapeworms will become up to eighteen meters long. They have tissues and in these tissues are cell structures. The mesoderm, a middle tissue layer, gives rise to muscular, reproductive, and water and salt regulating systems. There are about 10,000 species of flatworms that are called simple worms as they are truly flat, thin, have bilateral symmetry, a right and left side, top and bottom, and a head and tail end.

The adult parasitic flatworms have lost their motile structures (cilia) along the way. They have to rely on muscles for undulating motion or for creeping. This muscular activity has greater neutral activity, and more nerve cells concentrated in the brain. For some of the flatworms, simple tubes pick up dissolved wastes from internal cells and expel them from the body, much as kidneys do for other animals. In larger forms the gut is more branched, so all cells have a way of getting nutrients and disposing of metabolic wastes. They have no respiratory system, oxygen enters and carbon dioxide leaves their cells by diffusion through the thin, leaf like body.

In the evolution of more complex animals the ancestral flatworms occupied a position of importance in evolution. There is only one opening to the gut cavity, allowing food to enter and undigested resides will exit from the same cavity. Regional specialization is possible with this one way entering and existing as the food is processed more efficiently.

Movement of the flatworm is by means of two layers of muscles in its body wall and by thousands of cilia, which cover its lower surface. On the underside is the mouth, near the middle of the body. A flexible tub is formed as the throat pushes out of the mouth. This enables the flatworm to search for food. When the flatworm is not looking for food, the throat is pulled back inside the mouth. Food consists of decaying bits of plant or animal material. It will also eat insect larvae or other small water animals if they are small enough to swallow and slow enough to catch. These animals generally rely on continuous feeding.

There is an intestine that the throat opens into and it is located in the main digestive organ. The intestine has three main branches. Undigested materials must pass out through the mouth opening. There are masses of nerve cells that form the brain. From the brain to the body are two large nerves, which give off branch nerves to all parts of the body. The animal's movement is controlled by this simple nervous system. The flatworm will move away from bright light. It has eyespots that allow the animal to tell light from dark and the direction the light is coming from.

The planaria has several tissues, some organs, and systems. In addition to the nervous and digestive systems it also has covering, reproductive, and excretory systems.

Planaria and other similar flatworms get their food from the water. They are variety eaters. There are members of the flatworm phylum that live as parasites in larger animals. These will include the flukes and the tapeworms. The animal host provides all of their food. They have no digestive system at all and depend entirely on their hosts to digest their food for them. Unless their preprocessed food is always available, they will die or go dormant.

Cows, chicken, cats, dogs and other domestic animals usually have a variety of parasitic worms. These worms most likely will be tapeworms or flukes. These worms adapt well to the host and don't cause a lot of harm. Of course if the host animal dies, then the parasitic dies also as it cannot exist without the host.



Parasitic tapeworms come equipped with both male and female reproductive organs and each produces both sperm and eggs. They are called hermaphrodites. Parasitic tapeworms can fertilize themselves. There ability to reproduce is highly developed. They will produce millions of eggs. The eggs fill the old sections near the end of the tapeworm's body, these egg-filled sections break loose when they reach the end of the worm, then they are carried along through the host's intestine with the digested food. They leave the host in the feces, then when the feces fall to the ground to decay. The eggs are alive and get scattered all over. If another animal swallows the feces as food, the eggs hatch and grow inside the animal's body. If a host body does not swallow the eggs then they do not survive.

The tapeworms usually have two hosts, the adult worm lives in one kind of animal and the larva lives in another. The adult is called the main host and the one with larval is the alternate host.

Adult tapeworms live in the intestines of higher animals including people and are adapted to a parasitic life. As they have no mouth or intestine it is necessary to live in the intestine of the host and absorb molecules of food that the host has digested. They don't feel it necessary to move around very much as they have no eyes. Once the tapeworm finds a host the host finds the food, and protects both of them from enemies. Sometimes there is a problem in finding a host, many young parasites fail to find them. For the species to survive the highest rate of reproduction is necessary. People are the main hosts for several tapeworm species; alternate hosts are animals such as fish, cows, and pigs. The most common tapeworm found in dogs and rabbits is the alternate host.

Some people don't even realize that a tapeworm is inside their body if the person doesn't becomes sick.

It is important to realize that the parasitic flatworms have an effect upon the hosts they attack. They do not really have any great effect upon the communities in which they live, but they do fit in various food chains.

Roundworms are large groups of 12,000 species and are small, cylindrical, un-segmented worms that pervade the soil, bodies of most other animals, and also the environment of the water. They are very successful and can live almost anywhere, such as in soil, as parasites in higher animals, plants, and in water. Most of them are so small that they are not even noticed. These parasites are actually fairly large, but unseen. These worms are slender, round, and have no segments. Some of them are called nematodes as they are free living but the majority are parasites. They are a little more complex than the flatworms. They have a body wall made up of a covering layer and two layers of muscles and inside they are hollow. The intestine passes through this hollow space, as it is a tube with openings at each end, one for the mouth and one for the anus. The worm will take in it's food by the mouth, digest it, and absorb it as it moves along the intestine in the hollow space then wastes leave through the anus. The new food is not mixed with any older food.

Roundworms can cause drop damage from nematode infestation of the roots of plants in sandy soil and can be very costly. In domestic livestock and humans the roundworm infestations can capitulate to disease, lose of vitality, and even cause death. Most vertebrate life is infested with some form of roundworm.

There are lots of tiny roundworms living in soil, mud in lakes, ponds, or streams. They can attack the roots of the plants and really do a lot of intense damage. Some roundworms are caught by mold that forms sticky loops of fungus tissue and act as traps as roundworms crawl into them. There is a form of roundworm that can live in homemade cider vinegar and are harmless and often called "vinegar eels."

There are three types of parasitic roundworms and these are by far the most numerous of all parasitic worms. Trichina is a roundworm that may kill; it is less than one-fourth inch long and lives in the intestine of the host. The female worm will hatch eggs in the oviduct, inject the larvae into the blood vessels of the intestine and from there they will travel in the bloodstream to all parts of the host's body. The larvae will bore into the muscles and form cysts. When the host is eaten, the young worms come out of their cysts, grow up, and produce more young. One host passes the worms along to another host. Pigs and other animals are hosts of the trichina roundworm so that is why it is important to fully cook pork before eating.

The hookworm as an adult can only be half an inch long, but there may be thousands living in an intestine at once. Their food consists of blood from the intestine and this can cause the host to become very weak. Sometimes people experience fatigue because they are infested by hookworms. The hookworm is very plentiful in warm climates, especially in the southern United States, areas of low standards of living, as human waste is not disposed of safely. Wearing shoes can help in these warm climates. In the colder climates, the hookworm is killed by the frozen soil.

The most common parasitic roundworm is the Ascaris and is about eight inches long. It will feed on partly digested food in the human intestine. These worms can occasionally make a human feel badly, but seldom cause any trouble. In areas where sewage disposal is not sanitary, eggs from the female worms are often found as they leave the host in feces. Sometimes vegetables are grown in soil that is not sanitary and humans can swallow these Ascaris eggs. Children playing in the dirt may get this parasite. If large masses of these worms are in a human intestine it can become blocked. The adult worm boring a hole out through the intestine can cause infection. Death can even result from these infections.

Both the flat worms and the roundworms described above are found where sanitary conditions are very low and standards for disposal are not high or maintained. In China and other Oriental counties where human wastes are used as fertilizer and where fish are eaten raw, health problems due to flatworms will exist. The greatest problem from roundworms in man comes from hookworms, trichina worms, and ascaris. They are contracted from contaminated food or soil in which infested human waste was not properly disposed.

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