What is the similarity of flat and round worms? Comparative characteristics of flat and round worms

Flat and round worms have earned praise for the glory of dangerous parasites of humans and animals. Therefore, knowledge about the features of their structure and life activity will not harm each of us. What is the similarity of flat and round worms, what are the differences, what can be dangerous? The answers to these questions can be found in our article.

What is the similarity of flat and round worms?

The body of both flat and round worms is formed by real tissues that form their organs and systems. Let us recall that coelenterates did not have the above structures. Jellyfish and polyps consist of individual specialized cells. A common feature is the elongated shape of the body of worms of both types, and the size of their representatives, which vary considerably.

So, a flat worm, a parasite of cattle - bovine tapeworm, grows up to 10 meters. But the round pin is barely more than 10 mm. However, their size does not affect the scale of harm, which is equally great.

Comparison of flat and round worms

Habitat

Representatives of flat worms, like round ones, parasitize in the internal organs of many animals and humans. And the first are attached to their walls with the help of special structures located on the front side of the body. For example, the liver fluke has a mouth and abdominal suckers, and the pork tapeworm has a proboscis with hooks. Round worms of similar organs of attachment do not have, therefore they should constantly move towards to food masses. So, ascarids, which parasitize in the lumen of the small intestine of a person, "travel" through the body with a current of blood and oxygen.

Among the flatworms there are free-living species. Different types of planarians have mastered fresh, saltwater ponds, as well as forest litter. They feed by hunting smaller animals: crustaceans, hydroids, insect larvae and other worms.

Lifestyle

What is the similarity of flat and round worms? First of all, in the parasitic way of life. To reach pubertal age, they must undergo a complex life cycle. So, round worms - human parasites, which are called trichinella, in the process of development are replaced by several hosts. Pigs are infected by their larvae, eating various scrapings and meat of other infected animals. Further, their development and introduction of cyst worms into muscle fibers takes place. A person becomes infected with trichinella, eating poorly roasted pig meat. In the intestine, the larva of the parasite leaves the cyst, migrates and penetrates into the muscle tissue.

A flat worm, a parasite of the cat's fluke , develops in its life cycle in the body of two intermediate hosts: the mollusk and the fish. Only after this, he reaches the sexually mature stage in the ducts of the human liver and fish-eating animals: cats, dogs, wolves.

Body cavity

Based on the data that our table contains, roundworms have a number of more progressive features of the structure. One of them is the appearance of the body cavity. In flat worms, it is completely absent. Their body is flattened in the dorso-ventral direction and has the form of a leaf or ribbon. Intervals between organs they do not, because they are filled with a kind of connective tissue - parenchyma.

Round worms have a primary body cavity. Its characteristic feature is the absence of its own lining. Between the organs is constantly circulating cavity fluid, performing the most important functions. It carries oxygen to tissues and organs, and to the excretory ducts - the end products of metabolism. Because the cavity fluid is under pressure, it is involved in maintaining the body's constant shape of roundworms.

Features of digestion

Essential differences have these types of animals and in the peculiarities of the structure of the digestive system. Representatives of flatworms, regardless of their lifestyle, have a mouth opening and an intestine that blindly ends. This means that they can not simultaneously absorb food, and isolate its undigested remnants. And tapeworms are completely devoid of intestines, since they absorb already digested substances from the lumen of the small intestine of animals.

Round worms are parasites that have a through intestine. This causes a more intensive course of metabolism. Thanks to this structure, excretion of undigested residues does not interfere with the intake of new portions.

Structure of organ systems

In general, the systems of organs of flat and round worms have much in common. Their covers are represented by a skin-muscular sac. This structure consists of cells of the covering epithelium and several layers of muscles located under them. Such a structure makes possible the active movement of worms in space. Gas exchange and the process of isolation of substances also have the same mechanism.

The nervous system, consisting of nodes and processes, forms a variety of sensory organs of the worms. They are mainly located at the anterior end of the body. These are photosensitive eyes, tactile setae or papillae, organs of chemical perception and balance. Despite the significant difference in the type of reproductive system, flat and round worms have the same stages of development. This egg, larva and adult body.

The importance of flat and round worms

Understanding the similarity of flat and round worms, it is necessary to mention the biological role of these animals. Parasitizing in living organisms, they poison them with their own products of metabolism. For example, flukes cause inflammation of the liver, destruction of the walls of the bile ducts. Tape worms, absorbing nutrients and vitamins from the host's body, lead to its exhaustion, weakness and even loss of consciousness. Round parasites destroy many parts of plants, causing significant damage to the crop. Gallic, stalk and wheat nematodes are widely known.

Flat and round worms pose a serious threat to human health. To avoid infection, it is necessary to eat well-washed fruits and vegetables, heat-treated meat and fish, do not drink raw water, adhere to the rules of personal hygiene.

So, flat and round worms have many similar features of the structure. These include: habitat, elongated form, parasitic lifestyle, the presence of three layers of the body, the absence of the circulatory system. However, roundworms have a number of progressive features. First of all, this is the presence of the primary cavity and through the intestine.