Ciliary worms presentation. Ciliary worms presentation, report. Cattle

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Apollinaria

Eyelash worms

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In lakes, ponds, ditches on underwater objects, stones, in the axils of plant leaves.

Habitat

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The skin-muscle sac contains all the internal organs. It consists of one layer of integumentary cells (epithelium), bearing cilia, and three types of muscles located underneath them: annular, oblique, longitudinal.
The space between the skin-muscle sac and the organs is filled with parenchyma cells

Skin-muscle bag

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It is represented by two sections of the intestine: the anterior (mouth and pharynx) and the middle (highly branched and blindly closed). The mouth is on the ventral side and leads into the muscular pharynx. The worm that has fed on the whole has a branched intestine visible through the integument. In the intestines, food is digested and absorbed, and undigested remains are eliminated through the mouth. The intestine is closed, there is no anus

Digestive system

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Excretory system - protonephridia. The removal of waste products from tissues and organs occurs through numerous tubules. The tubule begins with cells with a bunch of cilia. Thanks to the movement of these cilia, liquid metabolic products flow from the tubules into two large longitudinal excretory canals.

Excretory system

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Circulatory, respiratory and nervous systems

There is no circulatory or special respiratory system. Worms breathe through the surface of their bodies, extracting oxygen from the water. Therefore, eyelash worms live in clean, oxygen-rich water.

In the anterior part of the body, nerve cells form a paired head nerve ganglion, from which nerve trunks extend, giving numerous branches of nerves to organs and tissues. There are organs of vision, taste, smell, touch, and balance.

Coelenterates mainly have radial symmetry; we will consider bilaterally symmetrical animals. This is a huge group, including about 99% of all animals, including flatworms, roundworms and annelids, mollusks and arthropods, chordates and many others (Fig. 1).

Rice. 1. Bilaterally symmetrical animals

Their body is characterized by bilateral symmetry and the presence of three cell layers: ectoderm, mesoderm and endoderm (Fig. 2). Coelenterates had only two cell layers.

Rice. 2. Bilateral symmetry and cell layers

In most bilaterally symmetrical animals, it is always possible to distinguish the anterior and posterior ends of the body, as well as the ventral and dorsal sides. Some bilaterally symmetrical animals secondarily lose this type of symmetry, for example, echinoderms.

The most ancient in origin, i.e., a primitive group of bilaterally symmetrical animals, are considered to be flatworms (Fig. 3).

Rice. 3. Flatworms

Flatworms do not have a specialized respiratory system, so their bodies are flat. In order for each cell to receive oxygen and release carbon dioxide, that is, for effective gas exchange, it is necessary that the cell be close to the external environment, which is why large flatworms have a body that is usually flat, like paper (Fig. 4).

Rice. 4. Representative of flatworms

Under the integument there are several layers of muscle, together they form a musculocutaneous sac. Flatworms do not have an internal body cavity, it is all filled with cells, all organs are united into systems: the digestive, excretory, reproductive and nervous systems of the organs. There is no circulatory system; nutrients are distributed directly through the intestines when present. The intestine is blindly closed and communicates with the environment only through the mouth.

The nervous system is represented by nerve ganglia located in the anterior part of the body, cerebral ganglia and nerve trunks extending from them, connected by jumpers (Fig. 5).

Rice. 5. Nervous system of flatworms

Some free-living flatworms have primitive organs of vision and balance. The discharge is carried out using special tubules and through the entire surface of the body. The body of a flatworm contains testes and ovaries, that is, male and female reproductive organs (Fig. 6).

Rice. 6. Reproductive organs of some flatworms

Such animals are called hermaphrodites. An interesting feature of most flatworms is the presence of a complex egg. It consists of a fertilized egg and several yolk cells, all of these cells together are covered with a hard protective membrane.

The organism in which an adult worm lives and reproduces sexually is called final owner.

The class Ciliated worms (Fig. 7) includes about three thousand mostly free-living species, with sizes ranging from microscopic to 30-40 centimeters.

Rice. 7. Class Ciliated worms

They live in sea or fresh waters, sometimes in humid land habitats. The integument of these representatives always has cilia, which help them swim or move along the bottom (Fig. 8).

Rice. 8. Eyelash worms

The sense organs of ciliated worms are much better developed than those of representatives of other classes; they often have an organ of balance. The olfactory organs are important, since with their help most ciliated worms hunt. Almost all ciliated worms have eyes (Fig. 9).

Rice. 9. Eyelash worm eyes

Ciliated worms are hermaphrodites and usually undergo cross-fertilization. Development is direct - a larva emerges from the egg, outwardly similar to the adult organism.

The ability of flatworms to regenerate is clearly expressed; accordingly, there is also asexual reproduction - a constriction appears on the body of the worm, which gradually divides its entire body into two parts.

The most famous are representatives of the order Planaria (Fig. 10), small flatworms found in freshwater bodies, where they crawl among aquatic plants.

Rice. 10. Planaria

In northern and central Russia, the milky-white planaria is very common, the largest among the rest (Fig. 11). Its length reaches three centimeters, its dark branched intestines are clearly visible through its white covers, and a pair of eyes can be distinguished on its head.

Rice. 11. Milky white planaria

Planarians move extremely smoothly and evenly due to the beating of cilia and small contractions of the body. They feed mainly on small aquatic animals.

The intestine has an extremely branched shape (Fig. 12), which is especially clearly visible in the milky white planaria if you observe it with a magnifying glass.

Rice. 12. Intestine of a milky white planaria

Planaria reproduce by laying eggs, which are immersed in a common protective cocoon. The main protective device of the planarians themselves is the mucus that abundantly covers their body. Planaria have extremely pronounced regeneration.

Rice. 13. Class Flukes

Typically, one of the hosts is a gastropod and the other is a vertebrate (Fig. 14).

Rice. 14. The owners of the flukes

Flukes produce a large number of eggs; the final host is a vertebrate; in its body, flukes can be found in the liver, intestines, gall bladder, and organs of the excretory system. The sizes of flukes range from several tens of microns to several centimeters. The body is flattened, leaf-shaped, there are two suckers - oral and ventral. The oral opening is located at the bottom of the oral sucker. The intestines are closed. The integument of flukes does not have cilia.

The nervous system is basic for representatives of the type. Discharge occurs through the surface of the body and with the help of tubules. Flukes are mostly hermaphrodite, but dioecious species are also found.

The eggs formed after the crossing of worms are hatched into the external environment with the feces or urine of the host, and a larva emerges from the egg, capable of swimming using the beating of cilia. For further development, it must infect a gastropod, inside which the larva undergoes metamorphosis and reproduces asexually (Fig. 15).

Rice. 15. Life cycle of the liver fluke

Then, dispersal larvae emerge from the body of the intermediate host and infect the definitive hosts (Fig. 16).

Rice. 16. Life cycle of the liver fluke

Rice. 17. Liver fluke (fluke)

It causes the disease fasciliosis, which manifests itself as hepatic colic and cholecystitis; this disease is common among sheep.

The adult worm is hermaphrodite and can reach three centimeters in length. Development occurs with the change of one intermediate host - a freshwater snail; infection of the final host occurs when ingesting water or food with its cysts. In the intestine, the cyst bursts, the young fluke comes out and penetrates the liver.

We learned about bilaterally symmetrical animals, examined the type Flatworms and its two classes - the Ciliated worms class and the Flukes class; in the next lesson we will complete the topic “Flatworms”.

Bibliography

1. Latyushin V.V., Shapkin V.A. Biology Animals. 7th grade. - Bustard, 2011.
2. Sonin N.I., Zakharov V.B. Biology. Diversity of living organisms. Animals. 7th grade. - M.: Bustard, 2009.
3. Isaeva T.A., Romanov N.I. Biology, 7th grade. - M.: Russian Word, 2013

1. Internet portal “shkolo.ru” ()
2. Internet portal “bono-esse.ru” ()
3. Internet portal “biolka.narod.ru” ()

Homework

1. Name the features of flatworms.
2. Name the most famous representatives of the class Ciliated worms.
3. Describe the lifestyle of worms of the class Flukes.

Class Ciliated worms
Ciliated worms are the most primitive group of lower worms; represented mainly by free-living forms. Body length varies from 5 mm to 50 cm. Turbellaria have the shape of a spindle, ribbon or drop and are covered with ciliated epithelium; glandular cells on the surface of the body secrete mucus.
The class Ciliated worms includes about 3,000 species living in marine and fresh water bodies, rarely in soil. A representative of free-living ciliated worms is the white (milk) planaria, which lives in fresh water bodies
Appearance and covers. The body of ciliated worms is elongated and leaf-shaped. Dimensions vary from a few millimeters to several centimeters. The body is colorless or white. Most often, eyelash worms are colored in different colors by grains of pigment located in the skin.
The excretory system first appears as a separate system. It is represented by two or several channels, each of which opens outward at one end, and the other strongly branches, forming a network of channels of various diameters. The thinnest tubules or capillaries at their ends are closed by special cells - stellate.
From these cells, bundles of cilia extend into the lumen of the tubules. Thanks to their constant work, there is no stagnation of fluid in the body of the worm; it enters the tubules and is subsequently excreted. The excretory system in the form of branched canals closed at the ends by stellate cells is called protonephridia.
The sense organs of ciliated worms are relatively well developed. The entire skin serves as an organ of touch. In some species, the function of touch is performed by small paired tentacles at the anterior end of the body.
The balance sense organs are represented by closed sacs - statocysts, with auditory pebbles inside. The organs of vision are almost always present. There may be one pair of eyes or more
The main feature of the nervous system of ciliated worms in comparison with coelenterates is the concentration of nervous elements at the anterior end of the body with the formation of a double node - the cerebral ganglion, which becomes the coordinating center of the entire body. Longitudinal nerve trunks, connected by transverse annular bridges, extend from the ganglion
The reproductive system is quite diverse in structure. It can be noted that, in comparison with coelenterates, ciliated worms have special excretory ducts for removing germ cells out. Ciliated worms are hermaphrodites. Fertilization is internal.
Reproduction. In most cases, sexually. In most worms, development is direct, but in some marine species development occurs with metamorphosis.
However, some eyelash worms can also reproduce asexually through transverse fission. At the same time, regeneration of missing organs occurs in each half of the body.

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Type Flatworms

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Type Flatworms (Plathelminthes). About 15,000 species of flatworms have been described. Some flatworms cause serious illness in humans. Fragment. Ciliated Tape Flukes. General characteristics of the type. External building. Most have a leaf-shaped or ribbon-shaped, bilaterally symmetrical body shape. Veils. The body of flatworms is protected by a single-layer epithelium. The epithelium and muscles form the skin-muscle sac. Musculature. The muscles of the skin-muscle bag are composed of several layers of muscle fibers. This muscle structure allows the worms to perform complex movements.

Round and flatworms

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Type flatworms type round, or protocavitary worms. Type Flatworms. The first three-layer animals with bilateral, or bilateral symmetry. The body is leaf-shaped or ribbon-shaped, flattened in the dorso-ventral direction. The space between the organs is filled with loose connective tissue (parenchyma) and fluid. Taxonomy. All planarians are predators and live in fresh and sea water. There are also terrestrial ones, but they live in damp places. Development is direct. Milky white planaria, Bipalia (terrestrial planaria), Many-eyed. Liver, Lanceolate, Feline (Siberian) flukes. Bovine tapeworm, Pork tapeworm, Broad tapeworm, Echinococcus, Common strapworm.

- Round and flatworms.ppt

The structure of flatworms

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Type Flatworms. The structure of flatworms. Flatworms. The structure of flatworms. Nervous system. Sense organs. Digestive system. Excretory system. Gas exchange and transport of substances. Reproductive system. Class Ciliated worms. Movement. Digestive system of ciliates. Eyelash worms. Turbellaria. Class Flukes. Digestive system of flukes. Reproductive system of flukes. Development of flukes. Flukes are extremely fertile. Class Tapeworms. The reproductive system is tape. Life cycles of tapeworms. Tapeworms.

- The structure of flatworms.ppt

Classes of flatworms

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Eyelash worms

Tapeworms

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Type of flatworms. Flatworms. Class ciliated worms. Representatives. Terrestrial ciliated worm rhynchodemus. Ciliated worm mesostome. Mediterranean eyelash worm Prosteceraeus. A typical representative of ciliated worms is the free-living worm, the white planaria. Internal structure of ciliated worms. Planaria, like other flatworms, is a three-layered animal. A skin-muscle sac is a characteristic feature of most worms. Cross section through the body of a planarian. Diagram of the internal organs of a planarian. Reproduction of eyelash worms. The reproductive system in animals first appears in ciliated worms.

Type Flatworms. Flatworms. Signs of flatworms. The appearance of the third germ layer during development. Type: Ciliated worms. Milk planaria. The body of a planaria. Single layer epithelium. Circular muscles. Planarian movements. Internal structure of planaria. Nervous system. Digestive system. Excretory system. Reproductive system. The eggs are covered with dense shells. Space between organs.

- Structure of planaria.pptx

The structure of a white planaria

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Flatworms. Plathelminthes. Annelids. Composition of the group. Variety of flatworms. Class Turbellaria. Food and movement. Capture of food by a white planaria. Structure. The structure of planaria. Covers of the body. Complication of the body cavity. Musculature. Muscle location. Throat and gut. The structure of a white planaria. Nervous system and sensory organs. Nervous system of a white planaria. Nephridia and accumulation buds. The structure of a white planaria. Thank you for your attention. - Structure of white planaria.pptx

Structural features of planaria

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