Taxonomy. The phylum Annelidae includes the classes: Oligochaetes, Polychaetes and Leeches.
Structure. Bilateral symmetry of the body. Body dimensions range from 0.5 mm to 3 m. The body is divided into a head lobe, a trunk and an anal lobe. Polychaetes have a separate head with eyes, tentacles and antennae. The body is segmented (external and internal segmentation). The body 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 of the body determines the high ability to regenerate.
The body wall is formed skin-muscle bag, consisting of a single-layer epithelium covered with a thin cuticle, two layers of smooth muscle: outer circular and internal longitudinal, and single-layer epithelium of the secondary body cavity. When the circular muscles contract, the body of the worm becomes long and thin; when the longitudinal muscles contract, it shortens and thickens.
Organs of movement - parapodia(available in polychaetes). These are outgrowths of a skin-muscular sac on each segment with tufts of bristles. In oligochaetes only tufts of setae are retained.
Body cavity secondary - in general(has an epithelial lining that covers the skin-muscular sac from the inside and the organs of the digestive system from the outside). In most representatives, the body cavity is divided by transverse partitions, corresponding to the body segments. Cavity fluid is a hydroskeleton and internal environment; it is involved in the transport of metabolic products, nutrients and reproductive products.
Digestive system consists of three sections: anterior (mouth, muscular pharynx, esophagus, crop), middle (tubular stomach and midgut) and posterior (hindgut and anus). The glands of the esophagus and midgut secrete enzymes to digest food. Absorption of nutrients occurs in the midgut.
Circulatory system closed. There are two main vessels: dorsal And abdominal, connected in each segment by ring-shaped vessels. Blood moves through the dorsal vessel from the rear end of the body to the front, and through the abdominal vessel - from front to back. The movement of blood is carried out thanks to the rhythmic contractions of the walls of the spinal vessel and the annular vessels (“heart”) in the pharynx area, which have thick muscle walls. Many people have red blood.
Breath. Most annelids have cutaneous respiration. Polychaetes have respiratory organs - feathery or leaf-shaped gills. These are modified dorsal antennae of the parapodia or head lobe.
Excretory system metanephridial type. Metanephridia They look like tubes with funnels. Two in each segment. A funnel surrounded by cilia and convoluted tubules are located in one segment, and a short tubule opening outward with an opening - an excretory pore - is in the adjacent segment.
Nervous system represented by suprapharyngeal and subpharyngeal nodes ( ganglia), peripharyngeal nerve ring (connects the suprapharyngeal and subpharyngeal ganglia) and ventral nerve cord, consisting of paired nerve ganglia in each segment, connected by longitudinal and transverse nerve trunks.
Sense organs. Polychaetes have organs of balance and vision (2 or 4 eyes). But the majority have only separate olfactory, tactile, gustatory and light-sensitive cells.
Reproduction and development. Soil and freshwater forms are mostly hermaphrodites. The gonads develop only in certain segments. Insemination is internal. Type of development - direct. In addition to sexual reproduction, asexual reproduction (budding and fragmentation) is also characteristic. Fragmentation is carried out through regeneration - the restoration of lost tissues and body parts. Marine representatives of the type are dioecious. Their gonads develop in all or in certain segments of the body. Development with metamorphosis, larva - trochophore.
Origin and aromorphoses. The following aromorphoses led to the emergence of the type: locomotor organs, respiratory organs, closed circulatory system, secondary body cavity, body segmentation.
Meaning. Earthworms improve the structure and fertility of the soil. The ocean worm Palolo is eaten by humans. Medical leeches are used for bloodletting.
Class Oligochaetes(Oligochaetes)
Representatives: earthworms, tubifex worms, etc. Most oligochaetes live in soil and fresh water. Detritivores(feed on semi-decomposed remains of plants and animals). There are no parapodia. The setae extend directly from the body wall. The head lobe is poorly expressed. Sense organs are often absent, but there are olfactory, tactile, gustatory, and light-sensitive cells. Hermaphrodites. Insemination is internal, cross. Development is direct, takes place in cocoon, which after fertilization forms on the body of the worm in the form of a belt, and then slides off it.
The role of earthworms in soil formation is enormous. They promote the accumulation of humus and improve the soil structure, thereby increasing soil fertility.
Class Polychaetes(Polychaetes)
Leech class
This is a summary for grades 6-9 on the topic "Ringed Worms". Select next steps:
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1. Find in the text of paragraph 1 the concepts indicated below and complete the sentences.
Zoology is the science of animals.
The main systematic category in biology is
2. Write what these scientists are famous for.
Aristotle - created a ladder of creatures.
A. Levenguk -
K. Linnaeus
M.V. Lomonosov -
3. Arrange the numbers of the following systematic categories in sequence from the “lowest” to the “highest” rank:
Answer: 1, 7, 2, 5, 3, 8, 4, 6.
4. What allows scientists from different countries to understand each other when describing animals?
5. After reading the text of paragraph 2, name the sciences that study animals:
Ethology is the science of animal behavior;
geography - the science of the patterns of distribution and distribution of animals on Earth;
Entology is the science of insects.
Ichthyology is the science of fish.
Ornithology is the science of birds.
6. Having studied the text of the paragraph, list the main areas of application of zoological knowledge.
There are examples of pairs or groups of cells that are in different locations and make essentially different connections, but that make similar connections to the cells they both contact and that share other common properties. However, a general search for such a grouping does not show anything statistically significant. One possible issue that may be important is that regional specialization of neurons, as discussed in, would create complications in any search for classes of neurons with equivalent synaptic potential.
Leeuwenhoek.
The entire body consists of one cell.
Because animals and plants feed on the same substances.
Roothoppers, radiolarians, sunfishes, sporozoans, flagellates, ciliates.
Root stalk - 7.
Formaminifera - 4.
Radiolaria - 1.
Volvox - 2.
Chlamydomonas - 5.
Euglena - 6.
Ciliates - 3.
All diseases come from dirty hands.
This does not mean that label-label agreement systems for determining synaptic connectivity do not exist, but simply that there are too few cells and too many variations exist to be inferred from the final connectivity data. A similar observation was made when a complete cell line was identified that was more reproducible than the nervous system. Although there are several suggestive repeat motifs, the overall layout of which progenitor cells produce is essentially disordered and mosaic, which correlates with position as a pattern in a line.
Lesson type: combined. Laboratory work .
Literature: Biology. Diversity of living organisms. 7th grade: educational for general education. institutions / N. I. Sonin, V. B. Zakharov. – 2nd ed., stereotype. – M.: Bustard, 2009. – 255 p.
Biology. Grade 7: lesson plans based on the textbook by N. I. Sonina, V. B. Zakharova / author. – comp. M. V. Vysotskaya. – Volgograd: Teacher, 2008. – 447 p.
Lesson progress: 45 min.
I. Organizational moment. 1 min.
II. Updating knowledge and skills, 10 min.
Frontal survey tests.
III. Learning new material, 25 min.
See lesson plans pp. 250-252.
IV. Consolidation of acquired knowledge. 5 minutes
Testing. See lesson plans pp. 251-252.
V. Homework.2 min.
Study the text on pp. 125-127; answer questions, prepare a speech about classes of ringlets according to plan: taxonomy, diversity, habitats, living conditions, external structure, lifestyle, internal structure, reproduction, role.
VI. Summarizing. 2 minutes.
Subject general lesson: “Types: flatworms, roundworms, annelids”
Target: Summarize, consolidate knowledge about the organization and life of worms.
Tasks: Educational: Ensure that schoolchildren retain knowledge of basic biological concepts; skills to reveal relationships and interdependencies between organs, organ systems, as well as connections between the structure of worms and their environment; continue to build knowledge about the evolutionary process. Educational: Continue to develop students’ environmental culture and personal hygiene skills; to develop students’ cognitive interest and practical work skills; desire to independently search for knowledge; develop creative thinking; Developmental: Develop students' attention and observation skills; logical thinking, ability to establish cause-and-effect relationships, generalize, draw conclusions.
Equipment: “Worms” tables, wet preparations of liver fluke and
Lesson type: generalization of knowledge.
Methods: story, conversation, independent work, testing.
Providing classes: CP, ICT tables “Worms”, wet preparations of the liver fluke and
roundworms, earthworms, cards for independent work.
Lesson plan:
I. Organizational moment. (Welcome, preparing the class for work, presence of students).
II. Motivation for learning activities. (Message of the topic, goals of the lesson, Use in further activities, showing the relevance of knowledge of the structure and functioning of the human body for everyone).
III. Updating knowledge.
What types of worms do we know?
IV. Generalization.
Exercise 1.
Write down the numbers of signs characteristic of each type of worm.
Flatworms________
Roundworms________
Annelids______
Signs
1 Bilateral symmetry of the body.
2.One layer of muscle
3. Many representatives develop with transformation
4. Closed circulatory system
5. All representatives have a circulatory system
6. Free-living people have sense organs
7. Excretory organs are represented by tubules with stellate cells
8. Powerful cuticle that forms the covering of the worm
9. Hermaphrodites
10. Regeneration
11. Larval development occurs in the intermediate host
Task 2.
On the given card, color the drawing of the worm's organ system (green for the digestive organs, red for the circulatory organs, yellow for the nervous system organs), write the name of the organs.
Task 3
Give reasons for the statement: “Among the various worms, annelids are the most
highly organized"_________
Task 4
Consider an earthworm, a roundworm wet mount, and a liver fluke.
What structural features allow them to live in a particular habitat?
Fill the table.
Task 5.
Write down the numbers of the correct statements.
What conclusion can be drawn based on these statements?
1.The development of a dense network of capillaries in earthworms is associated with cutaneous respiration.
2.The skin of the worm is formed by muscle tissue.
3.The blood of annelids carries nutrients from the intestines to all organs of the body.
4.Oxygen enters the body of free-living flatworms and carbon dioxide is removed through the skin.
VI. Reflection. Summarizing.
The sense organs in the human body work in concert; damage to some sense organs can be partially compensated by others. Such interaction and interchangeability testifies to the great and not fully understood capabilities of the organism.
Assess the degree to which the goals set during the lesson have been achieved.
Students' assessment of the progress and results of the lesson: Liked..., Didn't like..., Didn't understand..., Learned... It was difficult... Grade for the lesson to the teacher.
Teacher's assessment of the work of the class and students in the lesson.
VII. Homework message.
1- review everything about worms, prepare for testing
2-optional:
1 Prepare a report about one or two types of worms
2. Make a crossword puzzle
1. Continue filling out the pivot table on p. 13
2. Give reasons for the statement: “Among the various worms, annelids are the most highly organized”
Annelids for the first time have a secondary body cavity and the cellular structure of the skin. A circulatory system appears in the internal structure. The excretory system is represented by more developed metanephridia. Most ringlets are free-living, some have something like legs - parapodia. Everyone has bilateral symmetry. There are sense organs
3. Prove that the partitions present in the body of the annelid worm perform a protective function
Each segment of annelids is separated by a septum and has a full set of nerve ganglia, nephridia, annular vessels and gonads. If the integrity of one segment is violated, this affects the life of the worm to a small extent
4. List the structural features that help rings move well in different habitats
Some types of ringbills have parapodia and setae for locomotion. Those species that do not have parapodia have bristles or their body is covered with mucus for better gliding. The muscular system of all rings is represented by circular and longitudinal muscles
5. After studying the text of the paragraph, complete the diagrams
a) Digestive system of ringlets
b) Nervous system of ringlets
c) Sense organs of rings
6. What happens if the ring body is divided into several parts?
Regeneration may occur and the worm will restore the lost parts. That is, asexual reproduction will occur
7. Is it possible for sexual reproduction of ringlets without the formation of a girdle?
Maybe. In some polychaete worms living in the seas and belonging to the phylum Annelids, reproduction occurs in water, fertilization is external. But in most ringlets, reproduction occurs with the help of a belt
8. How are the number of eggs laid related to the care of offspring?
There is a direct relationship between the number of eggs laid and care for the offspring. Some polychaetes lay a few eggs, and the female guards them. This means that Annelids are more advanced than previous types of worms
9. Name all possible ways of feeding polychaetes
Among polychaete worms there are predators that feed on small marine animals. There are omnivores that filter water and eat plants.
10. Complete the sentences
The development of polychaetes occurs with alternation of life forms. Their larvae do not resemble adults. Each life form performs different functions: reproduction, dispersal, self-preservation. Some polychaetes are observed caring for offspring
11. Finish the diagram
The meaning of polychaetes in nature
1. Filter the water
2. They are fish food
3. They feed on the remains of dead animals
12. What are the differences in the diet of polychaete and oligochaete worms?
Oligochaete worms feed on organic matter from plant remains of the soil, and among polychaetes there are also predators, omnivores, and herbivores
13. What is common in the adaptations to endure unfavorable conditions among protozoa and oligochaetes?
To withstand unfavorable conditions, many protozoa form a cyst, and oligochaetes form a protective capsule, and enter diapause. These formations are similar in their functions
14. Using the text and pictures of the textbook, study the structure of an earthworm, and then complete laboratory work No. 3 “External structure of an earthworm.” Draw a drawing of an earthworm, marking the anterior and posterior ends of the body, segments, girdle, and bristles.
Draw a conclusion about what structural features allow worms to lead an underground lifestyle
Conclusion: The primary body cavity is supporting. It contains a liquid that gives the worm's body elasticity.
15. List the characteristic features of leeches:
1) Constant number of body segments
2) The presence of suction cups for attachment to the victim’s body or substrate
3) No bristles on the body
4) All leeches live in an aquatic environment
16. Name 2 types of food for leeches
17. Look at the pictures. Label what type and class these worms belong to
18. After studying the text of the paragraph, explain why leeches are more sensitive than other worms to changes in the environment
Leeches have a better developed nervous system
19. Is the statement true: “In dirty water it is difficult for oligochaetes to breathe, but leeches feel good”?
The statement is not true. Leeches are very sensitive to the purity of water and die if it is polluted. Oligochaetes withstand water pollution and can live for a long time in such reservoirs
20. What happens if leeches stop producing hirudia?
Hirudin is necessary to prevent blood clotting in the wound of the victim and in the stomach of the leech itself. If it is not produced, the leech will not be able to feed, as the blood will clot
21. For what purpose are leeches bought at the pharmacy?
Leeches are used in medicine to reduce blood pressure in cases of hypertension and the threat of hemorrhage and stroke
22. Indicate the characteristics corresponding to each class of annelids
A - 1, 2, 8, 10, 16
B - 4, 6, 11, 12, 17
B - 3, 5, 7, 9, 14, 15
Crossword No. 1. "Worms"
1) Give reasons for the statement: “Among the various worms, annelids are the most highly organized.”1. Capsule
3. Polychaetes
4. Cavity
5. Chain
6. Oligochaetes
8. Breathing
Keyword: rings
___________________________________________________________________
2) List the characteristic signs of leeches:
1)______________________________________________
2)______________________________________________
3)______________________________________________
4)______________________________________________
2. segmentation of protozoa, sponges, coelenterates, roundworms, flatworms, annelids, mollusks, echinoderms.
3. fertilization of protozoa, sponges, coelenterates, roundworms, flatworms, annelids, mollusks, echinoderms.
4. protection of protozoa, sponges, coelenterates, roundworms, flatworms, annelids, mollusks, echinoderms.
Please answer any of these points, otherwise the teacher will kill me and give me a 2, urgently needed by tomorrow, thanks in advance!)))
only from lime; b) only from a horn-like substance; c) from lime and horn-like substance; d) from a horn-like substance, lime and mother-of-pearl. 3. A shell formed by two valves has a) pearl barley, toothless mussels, and mussels; c) pond snails, reels, rapana b) squid, cuttlefish, octopus; d) slugs, grape snail. 4. The body of gastropods is divided into: a) head, torso and muscular leg; b) head, tentacles and torso; c) torso and muscular leg; d) head and torso. 5. Bivalves feed mainly on: a) filamentous algae; b) fresh crustaceans - daphnia and cyclops; c) organic particles and microorganisms; d) worms and insect larvae. 6. In the phylum of mollusks, eyes have: a) only bivalve eyes; c) gastropods and cephalopods; b) only cephalopods; d) representatives of all classes. 7. The most highly organized of mollusks include: a) gastropods; c) cephalopods; b) bivalve; d) spadefoot. 8. Gastropods move: a) with the help of a muscular leg; b) with the help of a muscular leg and tentacles; c) only due to water pushed out of the mantle cavity; d) with the help of tentacles and water pushed out of the mantle cavity. 9. Toothless respiration is ensured by the supply of oxygen through a) gills; c) the entire surface of the body; b) inlet siphon; d) lungs. 10. The largest animals among modern invertebrates: a) octopuses; c) deep-sea squids; b) tapeworms; d) jellyfish. II. Distribute representatives of the mollusc type into classes
1) Class Gastropods_________________ a)
pearl barley; g) oyster; 2) Class Bivalves______________ b) cuttlefish; e) octopus; 3) Class Cephalopods ________________ c) slug; h) pond snail d) grape snail; e) oyster;
1. Let's continue filling out the table.
2. Let us explain the above statement.
Annelids for the first time have a secondary body cavity and the cellular structure of the skin. A circulatory system appears in the internal structure. The excretory system is represented by more developed metanephridia. Most ringlets are free-living, some have something like legs - parapodia. Everyone has bilateral symmetry. There are sense organs.
3. Let's write about the protective function of partitions.
Each segment of annelids is separated by a septum and has a full set of nerve ganglia, nephridia, annular vessels and gonads. If the integrity of one segment is violated, this affects the life of the worm to a small extent.
4. Let us list the structural features of the rings.
Some types of ringbills have parapodia and setae for locomotion. Those species that do not have parapodia have bristles or their body is covered with mucus for better gliding. The muscular system of all rings is represented by circular and longitudinal muscles.
5. Let's finish the diagrams.
a) Digestive system of ringlets
b) Nervous system of ringlets
c) Sense organs of rings
6. Let's write about the division of the ring body.
Regeneration may occur and the worm will restore the lost parts. That is, asexual reproduction will occur.
7. Let's write an answer about the formation of the belt.
Maybe. In some polychaete worms living in the seas and belonging to the phylum Annelids, reproduction occurs in water, fertilization is external. But in most ringlets, reproduction occurs with the help of a belt.
8. Let's explain the relationship.
There is a direct relationship between the number of eggs laid and care for the offspring. Some polychaetes lay a few eggs, and the female guards them. This means that Annelids are more advanced than previous types of worms.
9. Let us list the feeding methods of polychaetes.
Among polychaete worms there are predators that feed on small marine animals. There are omnivores that filter water and eat plants.
10. Let's finish the sentences.
The development of polychaetes occurs with alternation of life forms. Their larvae do not resemble adults. Each life form performs different functions: reproduction, dispersal, self-preservation. Some polychaetes are observed caring for offspring.
11. Let's finish the diagram.
The meaning of polychaetes in nature
1. Filter the water.
2. They are fish food.
3. They feed on the remains of dead animals.
12. Let’s write down the differences in the nutrition of different worms.
Oligochaete worms feed on organic matter from plant remains of the soil, and among polychaetes there are also predators, omnivores, and herbivores.
13. Let’s write down the common adaptations of protozoa and oligochaetes.
To withstand unfavorable conditions, many protozoa form a cyst, and oligochaetes form a protective capsule, and enter diapause. These formations are similar in their functions.
14. Let us indicate in the figure the structure of an earthworm. Let's draw a conclusion.
Conclusion: The primary body cavity is supporting. It contains a liquid that gives the worm's body elasticity.
15. Let us list the features of leeches.
1) Constant number of body segments (33)
2) The presence of suction cups for attachment to the victim’s body or substrate.
3) Lack of bristles on the body.
4) All leeches live in an aquatic environment.
16. Let's name the types of food of leeches.
17. Let's determine the type and class of worms. 
18. Let’s explain the peculiarity of leeches.
Leeches have a better developed nervous system.
19. Let us explain the statement.
The statement is not true. Leeches are very sensitive to the purity of water and die if it is polluted. Oligochaetes withstand water pollution and can live for a long time in such reservoirs.
20. Write an answer about hirudia.
Hirudin is necessary to prevent blood clotting in the wound of the victim and in the stomach of the leech itself. If it is not produced, the leech will not be able to feed, as the blood will clot.
21. Let's name the role of leeches in medicine.
Leeches are used in medicine to reduce blood pressure in cases of hypertension and the threat of hemorrhage and stroke.
22. Let us indicate the characteristics of classes of annelids.
Classes of the type Annelids.
A - 1, 2, 8, 10, 16
B - 4, 6, 11, 12, 17
B - 3, 5, 7, 9, 14, 15
Let's write down the answers to crossword No. 1.
Answers:
1. Capsule
2. Belt
3. Polychaetes
4. Cavity
5. Chain
6. Oligochaetes
7. Tapeworm
8. Breathing
Keyword: rings
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