Taxonomy Type Flatworms Class Ciliated worms Representative: White (milk planaria) Class Flukes Representative: Liver. Type Flatworms

2. What kind of life do representatives of different groups of flatworms lead? How are the structural features of worms related to the image life. And the habitat?

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

representatives of different classes? How are the structural features of worms related to their lifestyle and habitat? 3. Using the example of the structural features of flat, round and annelid worms, list the signs of increased complexity of organization compared to coelenterates. 4.What diseases are caused by flatworms? What is their prevention? 5.What structural features and lifestyle are characteristic of representatives of the Roundworm type? 6. Why did annelids get this name? What is characteristic of the structure of each segment? 7. Based on what characteristics are annelids classified as more complex animals than those previously studied?

12 The body cavity of the roundworm a) filled with connective tissue b) filled with liquid c) filled with air d) absent
13 In each segment of the earthworm’s body, a) nerve ganglia are repeated b) excretory tubes c) annular blood vessels d) all answers are correct
14 An earthworm has a) sense of smell b) taste c) hearing d) no special sense organs
15 An earthworm breathes a) in an oxygen-free environment b) with atmospheric air c) both options are possible d) there is no respiration
16 The shell of the common pond snail is covered with a layer of a) lime b) 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 an open circulatory system c) an open circulatory system, the function of the heart is performed by two vessels in the front part of the body d) a single-chamber heart and an 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 The cancer heart has a) two sections: an atrium and a ventricle b) three sections: two atria and one ventricle c) one section d) there is no heart
21 The nervous system in cancer consists of a) suprapharyngeal ganglion b) subpharyngeal 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 the cross spider:
a) intracavitary b) partially extracavitary c) completely extracavitary d) liquid components are digested outside the digestive system, and solid ones in the spider’s stomach
24 The body of arthropods consists of:
a) head, chest and abdomen b) head and torso c) cephalothorax and torso 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 reaches insect tissues through diffusion through
a) walls of capillaries b) walls of tracheas c) walls of pulmonary sacs d) enters first the tracheas, then into the capillaries
27 Pisces belong to the type:
a) achordates b) hemichordates c) chordates
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's eyes are always open because they:
a) the eyelids have grown together and turned into a transparent membrane 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 environment b) variable, but does not depend on the temperature of the environment c) not constant and depends on the temperature of the environment
33 skin in reptiles
a) has sebaceous glands b) dry (without glands) c) has a small number of glands that secrete mucus
34 The heart of reptiles
a) three-chamber b) three-chamber, except for crocodiles c) four-chamber
35 Fertilization in reptiles
a) external b) internal c) both external and internal
36 Snakes
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) mesh b) ganglion c) diaphragm d) cuticle
38 The following element does not belong to the skeleton of the lower limb
a) tarsus b) femur c) tibia d) radius
39 Animals are characterized by radial symmetry of the body
a) mollusks b) flatworms c) coelenterates d) fish
40 Eliminate unnecessary things
a) scapula b) clavicle c) crow bones d) humerus
41 Bird Science is
a) poultry b) ornithology c) cynology d) zoology
42 Keel on the sternum of birds
a) promotes cutting through 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 their lack of 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) unchangeable and created by higher powers b) were first created and then evolved naturally c) arose and

Number of types: 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, during the course of evolution, bilateral symmetry, three-layer structure, and real organs and tissues appeared.

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

During embryonic development in three-layer animals have three layers of cells: outer - ectoderm, average - mesoderm, internal – endoderm. From each layer certain organs and tissues develop:

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

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

from the endoderm - the digestive system.

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

Digestive system includes the mouth, pharynx and blind intestine. Absorption of food and excretion of undigested residues occurs through the mouth. Tapeworms have a completely absent digestive system; they absorb nutrients over 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 there are flame (flickering) cells star-shaped, immersed in the parenchyma. A bunch of cilia (flickering flame) extends 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 as an excretory pore, through which waste products are removed from the body.

Nervous system ladder type ( orthogon). It is formed by a large head paired nerve ganglion (ganglion) and six nerve trunks extending from it: two on the ventral side, two on the dorsal and two on the sides. The nerve trunks are connected to each other by jumpers. Nerves extend from the ganglion and trunks to organs and skin.

Reproduction and development:

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

CLASS cilia worms

Milk planaria, a small aquatic animal, the adult is ~25 mm long and ~6 mm wide, with a flat, milky white body. At the front end of the body there are two eyes that distinguish light from darkness, as well as a pair of tentacles (chemical sense organs) necessary for searching for food. Planarians move, on the one hand, thanks to the work of the cilia covering their skin, and on the other hand, thanks 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 they meet intermediate cells, responsible for regeneration and asexual reproduction.

Planarians are predators 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 extend. Having captured the victim, the planaria sucks out its contents with its throat. Digestion occurs in the intestines under the action of enzymes (intestinal), and intestinal cells are able to capture and digest pieces of food (intracellular digestion). Undigested food remains are removed through the mouth.

Reproduction and development. Ciliated animals are hermaphrodites. Cross fertilization. Fertilized eggs fall into a cocoon, which the worm lays on underwater objects. Development is direct.

CLASS FLUKES

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

CLASS TAPPEWORMS

Bull tapeworm– a tapeworm, reaches a length of 4 to 12 meters. The body includes a head with suckers, a neck and a strobila - a band of segments. The youngest segments are located 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. The bovine tapeworm is a hermaphrodite: each of its segments has one ovary and many testes. Both cross-fertilization and self-fertilization are observed. The posterior segments, filled with mature eggs, open and are excreted with feces. Cattle (intermediate host) can swallow eggs along with grass; in the stomach, microscopic larvae with six hooks emerge from the eggs, which enter the blood through the intestinal wall and are carried throughout the animal’s body and carried into the muscles. Here the six-hooked larva grows and turns into Finn- a bubble containing the head of the tapeworm with its neck. A person can become infected with finches by eating undercooked or undercooked meat from an infected animal. In the human stomach, a head emerges from the finca and attaches to the intestinal wall. New segments bud from the neck - the worm grows. Bovine tapeworm secretes toxic substances that cause intestinal disorders and anemia in humans.

Development pork tapeworm has a similar character, its intermediate host, in addition to pigs and wild boars, can also be humans, then finches develop in its muscles. Development broad tapeworm is accompanied by a change of two intermediate hosts: the first is a crustacean (Cyclops), the second is a fish that has eaten the crustacean. The definitive host may be a person or a predator that eats the infected fish.

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

Questions for consolidation.

1. Who is called the intermediate host? Final?

6. Why is it dangerous to drink raw water or swim in bodies of water near livestock grazing? Why is it necessary 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 Flatworm type?

Lectures on zoology

Type Roundworms

Response Plan:

· General characteristics of Roundworms

Body structure of human roundworm

· Reproduction and development of Ascaris human

· Classification of Roundworms, variety of species

· The importance of Roundworms in nature and human life

a brief description of

Typical representatives of eyelash worms are planarians(Fig. 1).

Rice. 1.Morphology of flatworms using the example of milk planaria. A - appearance of planaria; B, C - internal organs (diagrams); D - part of a cross section through the body of a milk planaria; D - terminal cell of the protonephridial excretory system: 1 - oral opening; 2 - pharynx; 3 - intestines; 4 - protonephridia; 5 - left lateral nerve trunk; 6 - head nerve ganglion; 7 - peephole; 8 - ciliated epithelium; 9 - circular muscles; 10 - oblique muscles; 11 - longitudinal muscles; 12 - dorsoventral muscles; 13 - parenchyma cells; 14 - cells forming rhabdites; 15 - rhabdites; 16 - unicellular gland; 17 - a bunch of eyelashes (flickering flame); 18 - cell nucleus

general characteristics

Appearance and covers . The body of ciliated worms is elongated, leaf-shaped. Dimensions vary from a few millimeters to several centimeters. The body is colorless or white. Most often, eyelash worms are colored with grains of different colors pigment, embedded in the skin.

Body covered single-layer ciliated epithelium. In the integument there are skin glands, scattered throughout the body or collected in complexes. Of interest are the types of skin glands - rhabditis cells, which contain light-refracting rods Rhabdites. They lie perpendicular to the surface of the body. When the animal is irritated, the rhabdites are thrown out and swell greatly. As a result, mucus forms on the surface of the worm, possibly playing a protective role.

Skin-muscle bag . Under the epithelium is basement membrane, which serves to give the body a certain shape and to attach muscles. The combination of muscles and epithelium forms a single complex - skin-muscle sac. The muscular system consists of several layers smooth muscle fibers. Most superficially located circular muscles, somewhat deeper - longitudinal and the deepest - diagonal muscle fibers. In addition to the listed types of muscle fibers, ciliary worms are characterized by dorso-abdominal, or dorsoventral, muscles. These are bundles of fibers running from the dorsal side of the body to the ventral side.

The movement is carried out due to the beating of the cilia (in small forms) or the contraction of the skin-muscular sac (in large representatives).

Clearly expressed body cavities ciliated worms do not. All spaces between organs are filled parenchyma- loose connective tissue. The small spaces between the parenchyma cells are filled with aqueous fluid, which allows the transfer of products from the intestines to the internal organs and the transfer of metabolic products to the excretory system. In addition, parenchyma can be considered as supporting tissue.

Digestive system eyelash worms blindly closed. Mouth also serves for swallowing food, and for throwing away undigested food debris. The mouth is usually located on the ventral side of the body and leads into throat. In some large ciliated worms, such as the freshwater planaria, the mouth opening opens into pharyngeal pocket, in which it is located muscular throat, capable of stretching and protruding out through the mouth. Midgut in small forms of ciliated worms it is canals branching in all directions, and in large forms the intestine is represented three branches: one front, going to the anterior end of the body, and two rear, running along the sides to the rear end of the body.

Main feature nervous system ciliated worms compared to coelenterates is concentration of nerve elements at the anterior end of the body with the formation of a double node - the cerebral ganglion which becomes coordinating center of the whole body. They depart from the ganglion longitudinal nerve trunks, connected by transverse ring jumpers.

Sense organs in ciliated worms they are relatively well developed. Organ of touch All skin serves. In some species, the function of touch is performed by small paired tentacles at the anterior end of the body. Balance sense organs represented by closed sacs - statocysts, with hearing stones inside. Organs of vision are almost always available. There may be one pair of eyes or more.

Excretory system first appears as separate system. She is presented two or several channels, each of which one end opens outwards, A the other is heavily branched, forming a network of channels of various diameters. The thinnest tubules or capillaries at their ends are closed by special cells - star-shaped(see Fig. 1, D). From these cells, they extend into the lumen of the tubules bunches of eyelashes. 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.

Reproductive system quite diverse in structure. It can be noted that, in comparison with coelenterates, ciliated worms special excretory ducts appear For

excretion of germ cells. Eyelash worms hermaphrodites. Fertilization - internal.

Reproduction. In most cases sexually. Most worms direct development, but in some marine species development occurs with metamorphosis. However, some eyelash worms can reproduce and asexually through transverse division. In this case, in each half of the body there is regeneration missing organs.

Let's start the description with a little wince. worms. What can we do if such trump cards are available 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-layered cells led to much more advanced forms of organisms with a three-layered body structure. And then nature had to tinker for a long time, creating not just one, but entire ones.

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-layered)

…………………………………. K l . A. With. With. s

__________________________________________________________________________________

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

___________________________________________________________________________________

White planaria…. Liver fluke …… …………… Bovine tapeworm ___________________________________________________________________________________

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

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

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

………..
Body coverings and muscular system: skin-muscular sac - made of single-layer epithelium (maybe be with eyelashes) and three layers smooth muscles (circular, longitudinal and oblique).

Movement: contraction of muscles (flukes, tapeworms) or movement of cilia andmuscles (cilia worms).

Body cavity: absent , internal organs are located inparenchyma.

Digestive system:has two sections - anterior (mouth, pharynx) and middle (branches intestines). The intestine is closed, no anal opening and food residues are removed through the mouth. In tapeworms digestive system absent- 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 begins in the parenchyma stellate cell with a bunch of cilia, and the other flows into excretory duct. Channels are combined into one or two common channels ending excretory pores. Elementary the unit of the system isprotonephridia.

Nervous system:from suprapharyngeal ganglia(ganglia) and longitudinal nerves trunks, related crossbars(ladder type).

Sense organs: touch And chemosensitive cells. Free-living animals 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, zheltochniki.

1. 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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Guinea worm

There are worms that live in human blood. These include schistosomes. Their main habitat is blood vessels. However, they are able to penetrate various organs, causing symptoms of damage to the genitourinary system, liver, and kidneys.

The blood may contain larvae of some helminths. For example, in tapeworms this is how they spread throughout the body of the intermediate host. With the blood flow, the larvae migrate to various organs, where they attach and form cysts containing the heads of adult worms. When the latter enter the digestive tract of the final host, they attach to the intestinal wall, giving rise to a sexually mature individual.

Flatworms: general characteristics

The body of flatworms is capable of complex and varied movements.

All flatworms have common structural features:

• The outer cover is represented by the cuticle. In free-living individuals, it is covered with cilia; the surface of the body of worms is usually smooth.
• Under the outer covering there are several layers of muscle fibers.
• There is no body cavity.
• The digestive system has only one opening - the mouth. The intestine ends blindly. Some worms lack digestive organs altogether. Thus, tapeworms, which absorb nutrients throughout the body from the lumen of the host’s intestine, do not need them.
• There is no circulatory system or blood, as well as respiratory organs.
• The excretory system is represented by a network of tubes that penetrate the entire body.
• The nervous system is primitive. Near the pharynx there are several ganglia from which nerve trunks connected by jumpers extend. Sense organs are formed only in free-living individuals and some worms at the larval stages of development.

The system that is really well developed is the sexual system. Flatworms are hermaphrodites. Reproduction is possible with the participation of 2 individuals or by self-fertilization.

Flukes

The development cycle of trematodes is one of the most complex. Miracidia emerge from eggs released into the external environment. The latter feel comfortable in water and exist for some time as free-living organisms. The next stage is the introduction of miracidia into the first intermediate host. The larva does this using a special cutting apparatus on the head. The host is usually a mollusk.

Their life cycle can take place in several hosts and is accompanied by regular alternation

Here the miracidium turns into a sporocyst, which gives rise to the next stage of the development cycle - redia. Those, in turn, are the predecessors of cercariae, which leave the intermediate host and again enter the aquatic environment. Next, the development cycle follows one of two options. Cercariae transform into cysts directly in the external environment (attached to algae) or in the body of a second intermediate host (mollusk, fish, amphibian).

These are the longest worms with a transparent shell

Infection of the definitive host occurs when it eats infected organs of the intermediate host. The development cycle ends with the attachment of the head from the cyst to the intestinal wall and the development of the adult worm. The latter can reach significant sizes (for example, the wide tapeworm grows up to 10 m long).

For flukes, humans are the final host, but for tapeworms they can also be an intermediate host.

What symptoms occur when a person is infected with a helminth? The clinical picture of the disease is determined, first of all, by which organ is affected. Sexually mature worms usually live in the intestines, so the overall picture of the disease is dominated by symptoms characteristic of digestive disorders: nausea, gas formation, bowel problems, abdominal pain.

Helminths secrete waste products that, when released into the blood, cause poisoning and symptoms of intoxication (fever, fatigue, etc.). In addition, they are perceived by the immune system as an allergen. Therefore, helminthiases are often accompanied by symptoms of an allergic reaction (skin rashes, itching).