Flatworms name meaning and habitat. Aquatic and soil habitats Flatworm habitat and habitat

All worms can be divided into three types (flat, ringed, round), each of which has its own characteristic features. This type refers to invertebrates lacking a body cavity and possessing bilateral symmetry.

The main signs of the type of flatworms

digestive;
nervous;
sexual;
excretory.

This type has the presence of several systems and even the rudiments of organs

Circulatory system

Not available, but the function of the blood is performed by the parenchyma, consisting of connective cells. It is she who transports nutrients in the body.

Digestive system

Rather simplified, it consists of a pharynx and intestines.

The pharynx is powerful, can:

suck;
twist and wrap around your prey.

The intestine consists of two sections - anterior and middle, most often branched. It has a closed structure, so that all undigested waste exits through the mouth. The mouth opening is located closer to the middle of the body of the worm.

Free worms are mostly predators and they even have a kind of adaptation for capturing prey. This system is not observed in all classes; more primitive worms do not have it. For example, tapeworms feed on the entire surface.

excretory system

The excretory system is quite large and consists of many tubules that combine and lead to the excretory pores.

The parenchyma contains special cells that drive harmful substances into the tubules. For humans, these excretory products are very dangerous and toxic along with poison.

Muscular system

Presented, which form muscle fibers covered with epithelium. By contracting these fibers, the worms can move about.

Nervous system

In the upper part of the worm there are two head nodes, two nerve trunks descend from them. Longitudinal nerve trunks penetrate the body of the worm completely and are interconnected by transverse nerves, similar to a short flight of stairs.

With the help of dermal cilia, some worms can:

feel the temperature
other external stimuli.

And among free worms there are representatives who have developed organs of vision (pigments that react to light) and balance.

species diversity

There are three classes of this type:

Flukes.
Tape.
Eyelash worms.

Flukes: class representatives and characteristics

Class members:

General characteristics of the class flukes:

Tapeworms: representatives of the class and characteristics

General characteristics of the tapeworm class:

Class members:

is in stagnant water - ponds, ditches, very active. Covered with cilia, uses them to move on the water surface and attach to the bottom. The length is about 35 cm. The digestive system is developed, it feeds mainly on crustaceans and small invertebrates. Reproduction is sexual and asexual (divided in half, and then each half is completed). Wide range of habitat, found almost everywhere.
Ehrenberg mesostoma- a flat leaf-shaped body, slightly convex, transparent and colorless, in old worms it is brown. Unlike planarians, the intestines are straight, not branched. They live attached to aquatic plants. The mesostoma is predatory, preying on crustaceans, worms, insects and even freshwater hydras. It is able to tolerate the drying up of reservoirs, live in flooded meadows, puddles, and after their drying out, the eggs of the mesostom remain capable of development.
Ground worm rhynchodemus- soil worm, lives in damp places, most often under stones. Habitat Europe and North America. It can reach 12 mm, the color is brown with red longitudinal spots. Cilia are preserved on the ventral side of the body, moves by muscle contraction. Predator that eats insects.

general characteristics eyelash worms:

With a little frown, let's start the description worms. What to do if there are such trump cards in the thick "deck" of the natural diversity of life forms.

I write "trump cards" not only because " worms". The evolution of multicellularity from two-layer has led to much more perfect forms of organisms with a three-layer body structure. And then nature had to tinker for a long time, creating not one, but whole.

Somehow it even becomes a shame for all mammals, which represent only a separate class of organisms in the type of chordates. And here, "some kind of worms" - and whole three types: flatworms, roundworms and annelids.

Well, let's start everything in order, so:

……………… Type Flatworms (three layers)

…………………………………. K l . but. from. from. s

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.. Ciliary worms……………………….. Flukes……………………….. Tapeworms

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White planaria…. Liver fluke …… …………… Bull tapeworm ________________________________________________________________________________________________

……………………………………………….. More than 15 thousand species

Habitat : marine and fresh water bodies, moist soil, human and animal organisms.

……..
Structure: bilaterally symmetrical . For the first time in embryos, a the third germ layer – mesodermfrom which parenchymal cells and the muscular system develop. Body flattened.

………..
Integuments of the body and muscular system: skin-muscular sac - from a single-layer epithelium (may to be with eyelashes) and three layers smooth muscles (circular, longitudinal and oblique).

Motion: muscle contraction (flukes, tapeworms) or movement of cilia andmuscles (ciliary worms).

body cavity: missing , the internal organs are located inparenchyma.

Digestive system:has two sections - anterior (mouth, pharynx) and middle (branches intestines). The bowel is closed anal opening is missing and leftover food is removed. through the mouth. At the tapeworms digestive system missing- absorption of food by all cells of the body. As you remember, this is one of the forms of biological progress -.

excretory system: appears for the first time formed by a system of tubules. one end starts in the parenchyma stellate cell with a bunch of cilia, and the other flows into excretory duct. ducts combined into one or two common channels ending excretory pores. Elementary unit of the system areprotonephridia.

Nervous system: from supraesophageal ganglions(ganglia) and longitudinal nerves trunks, related cross jumpers(ladder type).

Sense organs: touch And chemosensitive cells. Free-living people have organsvision And balance.…………..

reproductive system: to usually hermaphrodites.Men'sreproductive system: testes, vas deferens, ejaculatory duct and copulatory organ. Women'sreproductive system: ovary, oviduct, uterus, yolk glands.

1. The appearance of the third germ layer -mesoderm.
2. The appearance of the excretory system - protonephridia.
3. Emergence of the nervous system ladder type.

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Number of species: about 25 thousand.

Habitat: They live everywhere in humid environments, including the tissues and organs of other animals.

Structure: Flatworms are the first multicellular animals in which, in the course of evolution, bilateral symmetry, three-layer structure, real organs and tissues appeared.

Bilateral(bilateral) symmetry - this means that an imaginary axis of symmetry can be drawn through the animal's body, while the right side of the body will be a mirror image of the left.

During embryonic development, three-layer animals are laid three layers of cells: outer - ectoderm, middle - mesoderm, internal - endoderm. Certain organs and tissues develop from each layer:

from the ectoderm, the skin (epithelium) and the nervous system are formed;

from the mesoderm - muscle and connective tissues, reproductive, excretory systems;

from the endoderm - the digestive system.

At flatworms the body is flattened in the dorsal-abdominal direction, there is no body cavity, the space between internal organs filled with mesoderm cells (parenchyma).

Digestive system includes the mouth, pharynx and blindly closed intestine. The absorption of food and the excretion of undigested residues occurs through the mouth. In tapeworms, the digestive system is completely absent; they absorb nutrients from the entire surface of the body, being in the intestines of the host.

excretory organs - protonephridia. They consist of thin branching tubules, at one end of which are fiery (flickering) cells star-shaped, immersed in the parenchyma. A bundle of cilia (flickering flame) departs inside these cells, the movement of which resembles the flickering of a flame (hence the name of the cells). Flame cells capture liquid decay products from the parenchyma, and cilia drive them into the tubule. The tubules open on the surface of the body with an excretory pore through which decay products are removed from the body.

Nervous system ladder type ( orthogon). It is formed by a large head paired ganglion (ganglion) and six nerve trunks extending from it: two on the ventral side, two on the dorsal and two on the sides. Nerve trunks are interconnected by jumpers. From the ganglion and trunks, nerves depart to the organs and skin.

Reproduction and development:

Flatworms are hermaphrodites. Sex cells mature in the sex glands (gonads). Hermaphrodite has both male glands - testes, and female - ovaries. Fertilization is internal, usually cross, i.e. worms exchange seminal fluid.

CLASS CILIATION WORMS

Dairy planaria, a small aquatic animal, the adult has a length of ~25 mm and a width of ~6 mm, the body is flat, milky white. At the front end of the body are two eyes that distinguish light from darkness, as well as a pair of tentacles (chemical sense organs) necessary for finding food. Planarians move, on the one hand, thanks to the work of the cilia covering their skin, on the other hand, due to the contraction of the muscles of the skin-muscular sac. The space between the muscles and internal organs is filled with parenchyma, in which intermediate cells responsible for regeneration and asexual reproduction.

Planarians are carnivores that feed on small animals. The mouth is located on the ventral side, closer to the middle of the body, from it comes a muscular pharynx, from which three branches of a closed intestine depart. Having captured the victim, the planaria sucks out its contents with its throat. In the intestine, digestion occurs under the action of enzymes (intestinal), intestinal cells are able to capture and digest pieces of food (intracellular digestion). Undigested food remains are removed through the mouth.

Reproduction and development. Ciliary - hermaphrodites. Cross fertilization. Fertilized eggs fall into a cocoon, which the worm lays on underwater objects. The development is direct.

CLASS FLUES

4 - sporocyst; 5 - redia; 6 - cercariae; 7 - adolescarium.

CLASS TAPE WORMS

Bull tapeworm- a tapeworm, reaches a length of 4 to 12 meters. The body includes a head with suckers, a neck and a strobile - a tape of segments. The youngest segments are at the neck, the oldest are sacs filled with eggs, located at the posterior end, where they come off one by one.

Reproduction and development. Bull tapeworm is a hermaphrodite: in each of its segments there is one ovary and many testes. Both cross-fertilization and self-fertilization are observed. The posterior segments, filled with mature eggs, open and, with feces, are brought out. Cattle (intermediate host) can swallow eggs along with grass, in the stomach microscopic larvae with six hooks come out of the eggs, which enter the bloodstream through the intestinal wall and spread throughout the body of the animal and enter the muscles. Here the six-hooked larva grows and turns into Finn- a vial, inside of which there is a tapeworm head with a neck. A person can become infected with fincas by eating undercooked or undercooked meat from an infected animal. In the human stomach, a head emerges from the finca, which is attached to the intestinal wall. New segments bud from the neck - the worm grows. Bull tapeworm emits toxic substances that cause intestinal disorders and anemia in humans.

Development pork tapeworm has a similar character, its intermediate owner, in addition to a pig and a wild boar, can also be a person, then Finns develop in its muscles. Development wide ribbon is accompanied by a change of two intermediate hosts: the first is a crustacean (cyclops), the second is a fish that has eaten a crustacean. The definitive host may be a human or a predator that has eaten the infected fish.

New concepts and terms: mesoderm, musculocutaneous sac, tegument, hypodermis, reduction, protonephridia (flame cells), orthogon, strobili, ganglion, gonads, hermaphrodite, direct and indirect development, definitive and intermediate host, miracidium, cercaria, finna, segment, armed and unarmed tapeworm.

Questions for reinforcement.

1. Who is called the intermediate host? final?

6. Why is it dangerous to drink raw water, swim in ponds near livestock grazing? Why is it important to wash your hands with soap after interacting with animals?

7. For which worms is oxygen harmful?

8. What aromorphoses led to the appearance of the type Flatworms?

Lectures on zoology

Type Roundworms

Answer plan:

General characteristics of roundworms

The structure of the body of Ascaris human

Reproduction and development of Ascaris human

Classification of roundworms, variety of species

The value of roundworms in nature and human life

check yourself 1. name the main groups included in the type of flatworms and characteristic distinguishing features using the example of representatives of each

2. What is the way of life of representatives of various groups of flatworms? how are the features of the structure of worms related to the image life. And habitat?

1) Name the main groups included in the type Flatworms, and their characteristic distinguishing features using the example of representatives of each group.

2) what kind of lifestyle do representatives of various groups of flatworms lead? How are the structural features of worms related to the way of life and habitat?

.Name the main classes of the type Flatworms and their characteristic distinguishing features using the example of representatives of each class. 2. What lifestyle do they lead

representatives of different classes? How are the structural features of worms related to their way of life and their habitat? 3. Using the example of the structural features of flat, round and annelids, list the signs of complication of organization in comparison with intestinal cavities. 4. What diseases do flatworms cause? What is their prevention? 5. What features of the structure and lifestyle are typical for representatives of the type Roundworms? 6. Why did annelids get such a name? What is characteristic of the structure of each segment? 7. Based on what features do annelids belong to more complex animals than previously studied

11 Flatworms a) have bilateral symmetry b) a skin-muscular sac c) a special excretory system d) all answers are correct

12 Ascaris body cavity a) filled with connective tissue b) filled with liquid c) filled with air d) absent
13 In each segment of the body of an earthworm, a) nerve nodes b) excretory tubes c) annular blood vessels d) all answers are correct
14 An earthworm from the sense organs has a) smell b) taste c) hearing d) no special sense organs
15 An earthworm breathes a) in an oxygen-free environment b) atmospheric air c) both options are possible d) there is no breathing
16 The shell of an ordinary pond snail is covered with a layer of a) lime b) a horn-like substance c) chitin d) silicon
17 In the circulatory system of the pond snail there are
a) two-chamber heart and one circle of blood circulation b) two-chamber heart and open circulatory system c) open circulatory system, the function of the heart is performed by two vessels in the front of the body d) one-chamber heart and open circulatory system
18 Gastropods include a) naked slug b) livebearer c) bitinia d) all answers are correct
19 The chitinous cover of arthropods performs the functions of a) protection b) thermoregulation c) gas exchange d) all answers are correct
20 Cancer heart has a) two sections: atrium and ventricle b) three sections: two atria and one ventricle c) one section d) the heart is missing
21 The nervous system in cancer consists of a) supraoesophageal ganglion b) suboesophageal ganglion c) ventral nerve cord d) all answers are correct
22 The abdomen of the cross-spider has a) three segments b) five segments c) non-segmented structure d) none of the answers is correct
23 The process of digestion in a cross-spider:
a) intracavitary b) partially extracavitary c) completely extracavitary d) liquid components are digested outside the digestive system, and solid ones in the stomach of a spider
24 The body of arthropods consists of:
a) head, chest and abdomen b) head and trunk c) cephalothorax and trunk d) head, chest and abdomen; cephalothorax and abdomen.
25 In insects, the number of pairs of motor limbs can be equal to
a) 3 b) 4 c) 5 d) all answers are correct
26 Oxygen to the tissues of insects is supplied by diffusion through
a) the walls of the capillaries b) the walls of the trachea c) the walls of the lung sacs d) enters first into the trachea, then into the capillaries
27 Fish are of the type:
a) chordateless b) semichordate c) chordate
28 The body is covered with bony scales: a) only in cartilaginous fish b) only in bony fish c) in all fish, with rare exceptions
29 Fish eyes are always open because they have:
a) the eyelids have grown together and turned into a transparent shell b) the eyelids are absent c) the eyelids are motionless
30 The spinal cord in fish is located
a) under the spine b) in the spinal canal, which forms the upper arches of the vertebrae c) above the spine
31 Circulatory system in fish
a) closed b) open c) open in cartilage and closed in bone
32 Fish body temperature
a) constant, and does not depend on the temperature of the medium b) variable, but does not depend on the temperature of the medium c) non-constant and depends on the temperature of the medium
33 skin of reptiles
a) has sebaceous glands b) dry (without glands) c) has a small amount of glands that secrete mucus
34 The heart of reptiles
a) three-chamber b) three-chamber, except crocodiles c) four-chamber
35 Fertilization in reptiles
a) external b) internal c) both external and internal
36 Snake is
a) legless lizards b) snakes c) a special group of reptiles
37 In all mammals, the thoracic cavity is separated from the abdominal septum
a) mesentery b) ganglion c) diaphragm d) cuticle
38 The following element does not belong to the skeleton of the lower limb
a) tarsus b) thigh c) lower leg d) radius
39 Animals are characterized by ray symmetry of the body
a) mollusks b) flatworms c) coelenterates d) fish
40 Eliminate the excess
a) scapula b) clavicle c) crow bones d) humerus
41 Bird Science is
a) poultry farming b) ornithology c) cynology d) zoology
42 Keel on the sternum of birds
a) contributes to the dissection of air during flight b) increases the area of attachment of the pectoral muscles c) does not matter as an adaptation to flight
43 What digestive organs arose in birds due to the absence of their jaws and teeth
a) goiter b) glandular part of the stomach c) muscular part of the stomach d) small intestine
44 Mammals spread across the Earth due to the fact that
a) were small in size b) fed their young with milk c) were warm-blooded d) all answers are correct
45 Fabrics first appeared in
a) protozoa b) coelenterates c) flatworms d) annelids
46 Darwin's theory states that all organisms
a) immutable and created by higher powers b) were first created and then evolved naturally c) arose and

1) name the main systematic groups of the type of flatworms and their characteristic distinguishing features, signs, using the example of representatives of each group.

Structural features Bilaterally symmetrical - a single cavity of symmetry divides the body into left and right halves. Development occurs from three germ layers: ectoderm, endoderm and mesoderm. The third germ layer appears for the first time in the course of evolution and gives rise to the development of parenchymal cells that fill the gaps between the organs and the muscular system. Left half Right half

Structural features Body sizes from 2-3 mm to 20 m. The body is elongated and flattened in the dorsal-abdominal direction; has a ribbon-like or leaf-like shape. The presence of developed organ systems is characteristic: muscular, digestive (absent in ribbon), excretory nervous and sexual.

Integuments of the body and the muscular system The cells of the epithelium and muscles are separate formations. The skin-muscle sac consists of a single-layer epithelium (in aquatic forms, the epithelium has cilia) and three layers of smooth muscles: annular, longitudinal, and oblique). Some representatives also have dorso-abdominal muscles. Movement is provided by muscle contraction (flukes and tapeworms) or by cilia of the integumentary epithelium and muscle contraction (ciliary worms).

The digestive system has two sections - anterior (mouth, pharynx) and middle (intestinal branches). The intestine is closed blindly, the posterior intestine and anus are absent. Undigested food remains are removed through the mouth. Tapeworms have no digestive system (represented by separate digestive cells).

Excretory system Formed by a system of tubules, one end of which begins in the parenchyma with a stellate cell with a bundle of cilia, and the other flows into the excretory duct. The duct unites into one or two common channels, ending in excretory pores.

Nervous system. Sense organs. It consists of supraglottic ganglions (ganglia) and longitudinal nerve trunks that run along the body and are connected by transverse nerve bridges. Sense organs - touch and chemical sense. Free-living people have organs of touch and balance.

liver fluke Hepatic flukes, usually up to 3 cm long, 1.3 cm wide. Hepatic flukes of the Opisthorchis order cause opisthorchiasis, early symptoms - liver enlargement, allergic reactions and gastrointestinal disturbances; symptoms late stage- pains radiating to the back, biliary colic, headaches and dizziness, insomnia. Treatment is with anthelmintic, choleretic and enzyme preparations. Also applies electromagnetic radiation high frequency.

Development cycle The life cycles of different genera are different. In species of the genus Fasciola, development occurs with one intermediate host (freshwater snail), and infection of the final host occurs when swallowed with water or eaten with coastal plants of the resting stage - adolescaria. In species of the genera Opisthorchis and Clonorchis, the second intermediate host is freshwater fish, and infection of the final host occurs by eating raw fish with invasive stages. In species of the genus Dicrocoelium, terrestrial lung snails and ants serve as intermediate hosts, and infection of the final host (usually a herbivore) occurs when an infected ant is eaten with grass.

Bull tapeworm (tapeworm) It affects cattle and humans, causing teniarinhoz. Infection with bovine tapeworm is especially common in equatorial Africa, Latin America, in the Philippines and parts of Eastern Europe. An adult bull tapeworm consists of more than 1000 segments and reaches 4-40 meters in length. The laying of the reproductive apparatus begins at about the 200th segment. Length of mature proglottids mm, width 5-7 mm. The scolex (head section) is equipped with 4 suckers without hooks (therefore unarmed). The life span of bovine tapeworm in the human intestine, if no deworming measures are taken, is years. A tapeworm produces ~ 600 million eggs per year, ~ 11 billion in a lifetime.

Development cycle Segments containing eggs are excreted from the human intestine (the main host). Together with the grass, they enter the stomach of the cow (intermediate host). Six hooked larvae emerge from the eggs, which penetrate into the blood vessels of the intestine and then into the muscles. In the muscles, the larva turns into Finns (a vial with a tapeworm head inside). When a person eats poorly processed finny meat, the tapeworm head attaches to the intestinal wall and begins to produce segments.

Structural features Bilaterally symmetrical. Sizes from a few micrometers (soil) to several meters (sperm whale nematode). They have a non-segmented body with a dense cuticle. The ciliary cover is partially or completely reduced. Body filiform, fusiform, non-segmented, round in cross section.

The digestive system is formed by the anterior, middle and hindgut. The foregut is differentiated into sections: mouth with cuticular lips, pharynx and esophagus. The middle and hindgut are not divided into sections. The digestive tract ends at the anus.

The excretory system is represented by 1-2 skin glands (modified protonephridia). These are large cells, from which two channels depart on the sides of the cell. At the posterior end of the body, the channels end blindly, and in front they open into the external environment with an excretory pore.

Nervous system. Sense organs Ladder-type nervous system. It is represented by the head nerve nodes (ganglia), the peripharyngeal nerve ring and several nerve trunks (dorsal and abdominal), median transverse bridges. The sense organs are represented by the organs of touch and chemical sense. Marine forms have light-sensitive receptors. Scheme of the roundworm nervous system: 1 - oral papillae with tactile endings and the nerves that innervate them, 2 - peripharyngeal nerve ring, 3 - lateral head ganglia, 4 - abdominal nerve trunk, 5 - lateral nerve trunks, 6 - ring nerves, 7 - posterior ganglion , 8 - sensitive papillae with corresponding nerves, 9 - anus, 10 - dorsal nerve trunk

Ascaris human Ascarids are large roundworms, their length can reach 40 centimeters. Most often affect the organs of the gastrointestinal tract, causing ascariasis. The favorite habitat of adults is the small intestine. Roundworms are bisexual worms. Ascaris females can produce more than 200 thousand eggs per day. Fertilized eggs from the human intestine enter the soil. They develop larvae. Infection occurs when drinking water from open reservoirs, eating poorly washed vegetables, fruits that have eggs with larvae. In the human body, the larva migrates: once in the intestine, it perforates its walls and enters the blood stream.

Structural features Bilateral symmetry of the body. Sizes from 0.5 mm to 3 m. The body is divided into the head lobe, trunk and anus. The polychaetes have a separate head with eyes, tentacles and antennae. The body is segmented (external and internal segmentation). The trunk contains from 5 to 800 identical ring-shaped segments. The segments have the same external and internal structure(metamerism) and perform similar functions. The metameric structure determines the high degree of regeneration.

Integuments of the body and muscular system The body wall is formed by a skin-muscular sac, consisting of a single-layer epithelium covered with a thin cuticle, two layers of smooth muscles (outer annular and inner longitudinal) and a single-layer epithelium of the secondary body cavity. With the contraction of the circular muscles, the body of the worm becomes long and thin, with the contraction of the longitudinal muscles, it shortens and thickens.

Body cavity Secondary - whole (has an epithelial vystilka). In most, the body cavity is divided by transverse partitions corresponding to body segments. The cavity fluid is a hydroskeleton and an internal environment; it is involved in the transport of metabolic products, nutrients and reproductive products.

The digestive system consists of three sections: anterior (mouth, muscular pharynx, esophagus, goiter), middle (tubular stomach, midgut) and posterior (hindgut, anus). The glands of the esophagus and midgut secrete enzymes to digest food. Absorption occurs in the midgut.

The circulatory system is closed. There are two vessels: dorsal and abdominal, connected in each segment by annular vessels. Through the dorsal vessel, blood moves from the posterior end of the body to the anterior, along the abdominal vessel from front to back. The movement of blood is carried out due to the rhythmic contractions of the walls of the spinal vessel and the annular vessels ("heart") in the pharynx. Many people have red blood.

The excretory system is of the Metanephidial type. Metanephridia look like tubes with funnels, two in each segment. The funnel, surrounded by cilia, and convoluted tubules are in one segment, and a short tubule that opens outwards with an opening - an excretory pore - is in the next segment.

Nervous system. Sense organs. It is represented by supraglottic and subpharyngeal nerve nodes (ganglia), which are connected to the peripharyngeal nerve ring and the abdominal nerve chain, consisting of paired nerve nodes in each segment, connected by longitudinal and transverse nerve trunks. Polychaetes have organs of balance and vision (2-4 eyes). Most have only olfactory, tactile, and light-sensitive cells.

Reproduction and development Soil and freshwater forms are mainly hermaphodites. Sex glands develop only in certain segments. Insemination is internal. The type of development is direct. Asexual reproduction is carried out by budding and fragmentation (due to regeneration). Marine representatives are dioecious. Development with metamorphosis, trochophore larva.