Variety of arachnids message. The variety of arachnids and their importance in nature and human life. General characteristics of arachnids. Nervous system and sense organs

Currently class of arachnids divided into 11 divisions. Let's consider some of them.

1. scorpions- inhabitants of hot countries. The largest, the imperial scorpion, grows up to 20 centimeters. The anterior pair of limbs is modified into claws, the abdomen is distinctly segmented, the segments are aligned along the axis. Of the more than one and a half thousand species of scorpions, 50 are dangerous to humans. The poisonous needle is at the end long tail. The venom of scorpions is poisonous, but usually non-lethal, although the bite is very painful. The most dangerous species is Leiurus quinquestriatus, but even children and weakened adults die from its bite, while the rest have swelling, fever, convulsions, and loss of consciousness.

2. Solpugi(they are also phalanges, bihorks, camel spiders, wind scorpions) are rather large spiders growing up to 7 centimeters. They have two pairs of chelicerae so powerful that they can pierce a human fingernail. Inhabitants South America they believe that the solpugs cut people's hair at night with their chelicerae. Salpugs are non-toxic, mostly nocturnal predators, including carrion, so cadaveric poison can get into the wound after perforation by chelicerae.

3. haymakers- representatives of this order resemble spiders, but the main difference is that their cephalothorax is connected to a segmented abdomen with a wide base, and not a thin stalk, like in spiders. Harvestmen have small body sizes (0.5–1 cm) and are incredibly long legs, up to 15 centimeters! Chelicerae are weak, so haymakers feed on small living creatures. When attacked by an enemy, the legs are thrown back - an example of self-mutilation, or autotomy.

4. Ticks- make up the largest group in the class of arachnids. Convinced pests, albeit tiny in size. Absorb both liquid and solid food they breathe through the body.

1) soil mites live in a layer of humus, feed on organic remains;

2) spider mites they settle on plants and feed on their juices, besides, they entangle everything with cobwebs. Pests of melons and vegetables, fruit trees;

5. Spiders- the most extensive detachment among the chelicerae.

1) web spiders- a family of spiders that weave nets, that is, large ring-shaped sticky webs where prey falls. The owners of the traps themselves crawl along the web along non-sticky threads. From the web, they weave houses and egg cocoons. Spiders from this family are sedentary, prefer not to change their place of residence. The most famous representatives are the cross-spider, black widow, karakurt. Karakurt lives in the Central Asian steppes, as well as in southern Europe and northern Africa. It has 13 characteristic bright spots on the surface of the abdomen, but it also happens to be pure black without spots. The bite of a karakurt is extremely dangerous, a person experiences terrible pain, spasms, a feverish state, an acute stomach, and is delirious. If treatment is not carried out or the body is weakened, the bitten may die;

2) wolf spiders- the family inhabited all regions of the planet, except for the poles, preferring wet places. Minks dig in top layer soil, but sometimes burrow to a depth of half a meter. More squat and flattened than web spiders internal organs located in the abdomen. A well-known representative of the family is the tarantula. Tarantula- a large spider, nocturnal predator, does not weave nets for catching prey. The South Russian tarantula (or mizgir) has a size of 3-4 centimeters, and this is the most big spider in Russia. Tarantulas are poisonous and dangerous to humans, but not fatal, at the bite site is felt strong pain, tissues swell.

1. general characteristics class of arachnids.

Arachnids were the first of the arthropods to inhabit the land and adapted to various terrestrial conditions of existence. In the course of evolution, they diverged into a multitude various forms. This class includes scorpions, haymakers, spiders, ticks, etc. external structure arachnids are characterized by the presence of a fused head-rudi and a dissected or fused abdomen. There are no antennae and compound eyes on the head (there may be several simple eyes). There are six pairs of limbs on the cephalothorax. The first two pairs (chelicerae and pedipalps) are highly modified and participate in the capture, retention and killing of prey. The remaining four pairs are walking legs. The abdominal limbs are reduced or modified into lungs and arachnoid warts. Respiratory organs - light, modified gill legs of ancient ancestors, trachea, or both at the same time. The excretory organs are represented by malpighian vessels. In the nervous system great development reaches the supraglottic node (brain). The number of nerve nodes depends on the degree of dismemberment of the body. The digestive system consists of three sections, but the structure of the intestine varies depending on the type of food. The most difficult digestive system in predatory arachnids with extraintestinal digestion. The degree of development of the circulatory system depends on the structure of the respiratory organs and the size of the animal. In small forms, the circulatory system may be absent. Arachnids have separate sexes. In connection with landfall, external fertilization is replaced by external-internal. Development is direct (with the exception of mites).

2. Variety and practical importance of arachnids.

The order of spiders includes very poisonous karakurts living in the steppes and deserts, as well as tarantulas found in the dry steppes of southern Europe, Kazakhstan and Central Asia. Many spiders benefit by exterminating harmful insects. Spiders feed on many small mammals, birds, lizards, frogs, predatory insects. material from the site

Ticks belong to arachnids, in most of which the body is not divided into segments (the cephalothorax and abdomen grow together). These are blood-sucking ticks - taiga and canine, which often attack humans. Their oral apparatus is very much modified and serves to pierce the host's skin and feed it with blood. A stuck tick is very difficult to remove. However main danger lies in the fact that dog and taiga ticks are carriers of pathogens of dangerous diseases: taiga encephalitis, typhus, tularemia. In addition, among the mites there are pathogens of human diseases such as scabies (scabies itch). A large group is made up of soil mites-saprophages. Feeding on rotting residues, they contribute to an increase in soil fertility.

The development of ticks occurs with metamorphosis. A six-legged larva emerges from the egg, it turns into an eight-legged nymph, followed by the adult tick stage.

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On this page, material on the topics:

• the practical importance of arachnids for humans
• Grade 7 biology variety of arachnids. ticks
• arachnids and practical significance
• essay on arachnids with literature
• arachnid systems summary

class arachnids, unlike crustaceans, live mainly on land, breathe with the help of trachea and lungs. The class includes three orders, on the representatives of which one can trace the process of fusion of body parts. So, in a detachment of spiders, the body is divided into a cephalothorax and abdomen, in scorpions it consists of a cephalothorax, anterior abdomen and posterior abdomen, in ticks all sections are merged into one shield.

Common signs of arachnids: lack of antennae, four pairs of walking legs, tracheal or pulmonary respiration, permanent perioral appendages - upper tentacles and leg tentacles. On the cephalothorax are four pairs of simple eyes, mouth organs and limbs (walking legs). The most common are spiders and mites.

Spider Squad

A typical representative of the order of spiders is cross spider. It can be found in forests, parks, on estates, in houses where they weave large trapping nets from cobwebs. In a spider, the first pair of oral organs are the upper jaws, equipped with sharp, downward-curved claws.

At the end of the claws, the excretory ducts of the poisonous glands open. The jaws serve the spider for killing prey and for protection. The second pair of mouth organs are the leg tentacles, with which the spider feels and turns the victim while eating.

Four pairs of jointed walking legs are covered with sensitive hairs. The abdomen of arachnids is larger than the cephalothorax. At the posterior end of the abdomen, spiders have arachnoid warts, into which the arachnoid glands open. The substance secreted by the glands hardens in air, forming arachnoid threads. Some glands secrete a strong and non-adhesive web, which goes to form a skeleton trapping net. Other glands secrete small sticky threads with which the spider builds a trapping web. Third glands secrete a soft silky web used by the female to weave a cocoon.

The spider entangles the victim in the trapping net with sticky cobwebs, sticks the claws of the upper jaws into the prey and injects into it a poisonous liquid that dissolves soft tissues and acts as digestive juice. Leaving the victim wrapped in a web, the spider steps aside, waiting for its contents to be digested. After a while, the spider sucks in partially digested food. So in spiders, partial digestion of food occurs outside the body.

The respiratory organs of the spider are represented by lung sacs that communicate with environment. In addition to them, the spider has tracheae in its abdomen - two bundles of respiratory tubes that open outwards with a common respiratory opening.

The circulatory system of a spider is basically the same as that of a cancer.

The role of the excretory organs is performed by the Malpighian vessels, the spider has one pair of them, but they branch. The hemolymph (blood mixed with lymph) of the spider washes these vessels and the metabolic products exit through the gaps, then enter the intestines and are then excreted.

Nervous system formed by the subpharyngeal node, the brain, from which the nerves depart to various organs.

Spiders have numerous and varied sense organs: organs of touch (hairs on the body of the spider and on the tentacles), smell and taste (on the tentacles and walking legs), taste organs are also present on the lateral parts of the pharynx; organs of vision (eight simple eyes). Some spiders are able to distinguish color, especially those. which are looking for prey on the flowers of plants (crab spiders).

Spiders are dioecious animals. Females are larger than males. In autumn, the female spins a cocoon of cobwebs and lays her eggs in it. In it, eggs hibernate, and in spring spiders hatch from them. Most spiders are beneficial: many small mammals, birds, lizards, and some insects feed on them. Among the spiders there are also poisonous ones - tarantula and karakurt. They are very dangerous for humans and pets.

Squad of pincers

In most representatives of the order of ticks, the body does not have a clear division into segments or sections. There are a lot of ticks. Some of them live in the soil, others - in plants, animals and humans.

Unlike spiders, flares have an indirect development. A six-legged larva emerges from the egg, in which, after the first molt, a fourth pair of legs appears. After several molts, the larva turns into an adult.

Red spider mite settles on the leaves of cotton and other valuable plants. It reduces cotton yields and causes plant death.

flour mite settles in onions and grains. Eating the germ of the future plant in the grain, it causes the death of the seeds. He causes damage food products in warehouses. for example, various cereals, bread products, sunflower seeds. Cleanliness and ventilation of the premises where food is stored is one of the main measures to combat flour mites.

scabies mite (scabies itch) causes diseases such as scabies in humans. Females of this type of mites are introduced into the more delicate areas of human skin and gnaw their moves in it. Here they lay their eggs. Young flares come out of them, again gnawing passages in the skin. Keeping your hands clean prevents this dangerous disease.

Scorpion Squad

Scorpions live in countries with a warm and hot climate, and are found in a wide variety of habitats: from moist forests And sea ​​coasts to barren rocky areas and sandy deserts. Often scorpions settle in human dwellings.

Scorpions are mostly viviparous, some species lay eggs in which the embryos are already developed, so that juveniles soon hatch. This phenomenon is called ovoviviparous. A scorpion becomes an adult a year and a half after birth, making 7 molts during this time.

A scorpion sting is a means of attack and defense. On small invertebrates, which usually serve as food for a scorpion, the poison acts almost instantly: the animal immediately stops moving. For small mammals Scorpion venom is mostly lethal. For a person, a scorpion sting is usually not fatal, but a number of cases are known with very serious consequences and even death.

Scorpion Squad

Scorpion Squad (Scorpiones) are the most ancient arachnids. About $600$ species are known. For scorpions, the dismemberment of the body is characteristic: a fused cephalothorax, $6$ segments of the pre-abdomen and meta-abdomen. The telson has a characteristic swelling containing a poisonous needle. Scorpions live in countries with warm climate. These are predators that hunt at night, mainly for insects. Characterized by live birth and care for offspring. The female carries the offspring on her back for some time, having thrown the metabelly and a poisonous needle onto her back. The most common scorpions in Central Asia, In the Crimea, in the Caucasus, a motley scorpion.

Detachment Zhgutopodye, or Telifon

Phones (Uropygi) are relatively large, up to $7.5$ cm arachnids, few in number, living mainly in the tropics. In Russia, in the Ussuri region, there is only one type of telephones.

Remark 1

characteristic feature flagellated is the presence in place of the first pair of walking legs of long sensory appendages and a special long, divided into segments, caudal filament. This thread is a feeling organ.

Telephons are nocturnal predators. These animals orient themselves in space, mainly due to the seismic sense and tactile organs located on the sensory limbs. Telifons have anal glands that spurt out a caustic liquid when threatened.

Solpuga Detachment

Solpuga Detachment (Solifugae), or phalanges are major representatives arachnids living in deserts and steppes. About $600$ species are known.

Character traits:

• unfused cephalothorax;
• powerful claw-shaped chelicerae are closed in a vertical plane;
• breathing with trachea.

Salpug phalanges are not poisonous. They hunt at night, feeding mainly on insects. The female lays her eggs in a burrow and takes care of her offspring.

Squad of false scorpions

Squad of false scorpions (Pseudoscorpiones) are small arachnids from $1$ to $7$ mm. They have large claw-shaped pedipalps. Fused cephalothorax and abdomen undivided into anterior and posterior abdomen.

False scorpions live under the bark, in the forest floor, you can meet them in a person's dwelling. Predators, feed on small insects, mites. In houses you can meet a book false scorpion. It appears in damp rooms, conducive to the development of small mites and insects.

Detachment Haymakers

Detachment Haymakers (Opiliones) is a common group of arachnids that have an external resemblance to spiders. They differ from spiders in the absence of a constriction in the region of the cephalothorax and abdomen. Harvestmen have a jointed abdominal region and claw-shaped chelicerae.

There are haymakers on soil surfaces, on the walls of fences and houses. In the bark of trees. Nocturnal predators feed on small insects. They actively hunt for their prey, do not emit a web.

Remark 2

A characteristic property of harvestmen is autotomy - self-mutilation when captured by other predators. In this case, the lost legs are not restored.

Squad Spiders

Squad Spiders (Aranei) is the largest order of arachnids and includes more than 27,000 species.

Spiders have characteristic morphological features:

• a fused cephalothorax and a fused abdomen of a rounded shape stand out in the body, between which there is a constriction;
• chelicerae hook-shaped, contain ducts of poisonous glands;
• short pedipalps look like tentacles;
• spider warts are located on the underside of the abdomen.

Wide ecological radiation of spiders determined complex behavior in connection with the use of the web throughout life.

1. From the web, a dwelling is built between branches, leaves or in a soil hole.
2. The cobweb envelops the oviposition with the formation of an egg cocoon.
3. Small spiders can secrete a long thread that carries them away with the wind over long distances.
4. The web is widely used when catching prey, during the mating season.

Only two-lung spiders live in Russia, most prominent representatives which are the cross spider, house spider, silver spider, tarantula.

For humans, the spider is dangerous - karakurt, which can be found in the steppe dry regions of the Caucasus, the Volga region, and Central Asia.

Ticks

Among the tick-like arachnids, there are three orders.

Sections: Biology

Lesson Objectives:

• educational:
to acquaint students with the diversity of arachnids and their significance in nature and human life, to study measures of protection against ticks;
• developing:
develop cognitive interest in the subject, broaden horizons, generalize, highlight the main thing;
• educational:
carry out environmental and hygienic education.

Equipment: presentation for the lesson, made using Microsoft Power Point (Annex 3)

Lesson type: combined.

During the classes

Organizing time.

Knowledge update.

Individual survey.

1. Find features of adaptability in the external structure of the cross-spider to the terrestrial lifestyle.
2. In internal structure spider, highlight the features that distinguish it from cancer. Why are spider and crayfish classified as the same type?
3. Determine the systematic position of the cross-spider.

Working with didactic cards

Card #1

What is the significance of the web in the life of a cross-spider?

Prove with the help of examples that the cross-spider has a more complex structure than the earthworm.

Card #2

1. Choose and write down the correct judgments

The body of spiders consists of a cephalothorax and an undivided abdomen.

Spiders breathe oxygen dissolved in water.

Spiders weave trapping webs with their legs.

The web can serve as a means of protection for the spider, movement, breeding and protection of offspring.

All spiders breathe atmospheric air.

Digestion of food occurs in the spider's sucking stomach.

2. Sign the name of the main sections of the spider's body.

Learning new material

Creation problem situation and posing the problem of the lesson. Sample conversation questions

What other animals belong to the arachnid class?

difference and similarity

Significance in nature and human life.

The topic of our lesson is "The variety of arachnids and their significance in nature and human life. General characteristics of arachnids."

IN ancient years Arachne lived
Woven from thin threads of cloth
And proud of her labors,
Determined to compete with the gods.
With the goddess Athena, the dispute withered
Arachne's work was more beautiful
Goddess, with anger tore her,
She turned Arachne into a spider
So that the weaver forever weaves a web.

Guys, what do you think is the name of the science that studies the arachnid class? (Arachne is a spider, logic is a science).

In the last lesson, we got acquainted with the lifestyle and structure of spiders. But this class also includes other animals.

During the lesson, students complete the table number 1. "Comparative characteristics of spiders, scorpions and ticks (Appendix 1).

Comparative characteristics of spiders, scorpions and ticks.

The diversity and importance of arachnids.

Spider Squad. Main idea: "But still they are cute!"

Sample conversation questions

What is the way spiders feed?

With the help of what formations do spiders hunt?

What type of digestion do spiders have?

What do spiders use to navigate?

In total, about 35,000 species of spiders are known. The length of their body is from 0.1 to 5 cm. The main food is the liquid tissues of insects, which the spiders catch by rushing from an ambush or with the help of a web. Spiders are found at almost all inhabited latitudes and elevations: they were found on the slopes of Everest at 6700 m above sea level and caught (juveniles) 600 m from the surface of the earth. Some species live in water.

Many spiders build various shelters, "houses" from the web; living in minks - line the minks with cobweb "rugs" and make cobweb "doors". The silver spider (Argyroneta aquatica), living under water, builds a "diving bell" from the web, into which it draws a supply of air and in which it lives. Many spiders "pack" the caught prey into web "packages". The cobweb is also good for insurance: they probably saw how a frightened spider falls, releasing a cobweb thread behind it. Then, along this thread, he will rise up; he cannot wind the cobweb back, but the good does not disappear - the spider eats it. Some spiders sleep hanging on such a cobweb. Any careless movement of the enemy sneaking in the night - and the spider disappears. And those who sleep in more comfortable conditions pull on signal threads. And you can also fly on the cobweb. Like paragliding. So spiders settle in new places. If spiders could speak, they would probably say: "the web is our everything!".

This is interesting! (Annex 2)

The ability of spiders to secrete a silk-like thread has repeatedly led to attempts to use them like silkworms, but these experiments have not been successful. The main difficulty is that you need to feed the spiders with live insects, and more than 1.3 million spiders are required to get one kilogram of fiber fast enough! At one time, the crosshairs of optical instruments, such as theodolites, levels and telescopes, were made from cobwebs.

Almost all arachnids are predators. They seize and tear the prey with pedipalps, but swallow food in liquid, less often in a highly crushed state. The spider injects digestive substances into the prey and sucks out the products of extraintestinal digestion. The spider's mouth is covered with bristles to prevent large particles from entering the intestines, and the front of the intestine works like a pump. Spiders use web gear to catch prey. .

Question: In the dead of night, tarantulas come out to hunt. The tarantula waits for prey, jumps on the lancet snake (one of the most poisonous snakes), bites through the skin and injects poison, providing itself with food for a very long time. How does the tarantula know about the approach of the victim? How does a spider eat?

Answer: (The tarantula feels the movement of the earth when the snake crawls, suddenly pounces, the poison immobilizes the snake. Digestion of food occurs outside the body, i.e. in the victim, the spiders absorb the digested food.

Question: What kind of spider is born in water, lives in water, hunts and dies?

All my friends are on land
Well, I live in a pond.
When necessary, the house is airy
I'll drive it under water.

Answer: The silver spider builds under water an air bell from the web, from which the threads of the trapping net stretch. The spider more often pursues aquatic invertebrates than catches in a net, but eats the prey in the bell.

Physical education minute

Tick ​​squad (48,000 species) Main idea "Almost like aliens"

The tick is common name for small arachnids. The length of their body usually does not exceed 1 mm, very rarely up to 5 mm. Unlike other arachnids, the body of ticks is fused and not divided into cephalothorax and abdomen; ticks do not have eyes. Chelicerae in ticks that feed on solid food are of a gnawing type, and in those that feed on liquid food, chelicerae form a piercing-sucking proboscis. Ticks live in the soil, among fallen leaves, on plants, in water, in human homes. They feed on rotting plant debris, small mushrooms, suck plant sap, participate in soil formation, in human living quarters microscopic mites feed on dry organic residues contained in dust. Ticks produce many young, but do not take care of the brood.

Spider mites damage various cultivated plants.

Barn mites spoil the grains of cultivated cereals stored in granaries. Ticks are the second carrier of human disease after mosquitoes, they are often contagious and poisonous.

For example, scabies itchs penetrate the skin of humans and animals, gnaw through passages there, causing a disease - scabies. Taiga ticks carry a viral disease - taiga encephalitis.

Measures of protection against ticks. (Teacher's story.)

First aid for a tick bite

When bitten by a tick, do not try to tear it off by force, but lubricate it vegetable oil, wait 30 minutes, grasp with tweezers and gloved fingers as close to the skin as possible and slowly pull out. If the head of the tick remains, then treat this place with iodine or alcohol and rinse twice a day warm water until complete healing.

If at the time of removing the tick you accidentally crushed it with your fingers, in no case do not touch your eyes and mucous membranes of the mouth, nose until you wash your hands with soap and water.

A person who has been attacked by a tick should definitely consult a doctor.

Order of scorpions (750 species) Main idea "Formidable animals"

By appearance they could be mistaken for cancer, the resemblance between them is only external: the scorpion has no antennae, its claws are armed not with the chest, but with the head limbs, it breathes with the help of lung sacs and the total number of limbs is 8. The structural features of scorpions are a jointed abdomen, the back section of which ends with a poisonous sting. The sting serves both for hunting and for attack. The venom of a scorpion kills insects, and a person can cause severe pain and cause severe swelling. Female scorpions do not lay cocoons, but give birth to live young, unlike spiders.

2. SIGNIFICANCE OF ARCHINA IN NATURE AND HUMAN LIFE

What role do you think spiders play in nature? Are they beneficial to humans?

First of all, they destroy a huge number of flies - carriers of pathogenic microbes. Secondly, scientists, studying the life and anatomy of spiders, find answers to many mysterious questions about the origin and formation of life on Earth, its development and the amazing adaptation of living beings to changing environmental conditions.

I. Links in the food chain

II. Destroy agricultural pests (spiders).

III. Improve soil structure (soil mites).

IV. Poisonous animals that harm human health (karakurt, scorpion)

V. Reduce the yield of agricultural plants (spider mites). Spider mites damage various cultivated plants.
VI. Destroy food stocks (barn mites) Grain mites spoil the grains of cultivated cereals stored in granaries.

VII. Cause human diseases (scabies mite).

VIII. They are carriers of pathogens of human diseases (taiga tick).

3. General characteristics of arachnids. (Conversation)

GENERAL CHARACTERISTICS OF ARCHINA

Arachnids are one of the oldest inhabitants of land. Their body consists of a cephalothorax and abdomen or is fused. (Ticks have a fused body.) There are 4 pairs of walking limbs. Arachnids have simple eyes and no antennae.

Respiratory organs - trachea and lung sacs. About 60,000 species are known.

Arachnids - typically - land arthropods

Main orders - spiders, scorpions, ticks

They play an important role in nature and human life.

When hiking in the forest, you need to protect your body with clothes from ticks.

Anchoring

1. Answer the questions.

1. What order of arachnids do these animals belong to?

Under what numbers are scabies and taiga mites?

To which order of arachnids do these animals belong?

Under what numbers are the tarantula spider and karakurt represented?

2. Solving the puzzle "Arachnids"

1. Ticks that harm crop production.

2. poisonous spider, whose name in translation into Russian means "black widow".

3. An arachnid animal with a jointed abdomen, ending with a poisonous sting curved in the form of a claw.

4. A spider that lives in ponds and backwaters of rivers

5. A stray spider whose bite causes a painful swelling that is not life-threatening.

6. Tick, which is a carrier of pathogens of taiga encephalitis

7. A tick that gnaws through human skin and causes unbearable itching.

2. Solving biological problems.

Task #1

Are they relatives or not?

Two students were looking at a collection of insects and noticed a scorpion. One claimed that it was a representative of crustaceans, and the other that scorpions belong to spiders. Which of them is right?

Task #2

Karakurt, tarantula. Which of these spiders is the most poisonous? By what signs can these spiders be recognized in nature?

Task #3

Even those few spiders that have switched to an aquatic lifestyle breathe atmospheric air. What respiratory organs are developed in spiders?

Task #4

Among the arachnids, there are animals that the agronomist, the doctor, and the veterinarian deal with. What are these arachnids? Why are people of different specialties interested in them?

Task #5

Task number 6

Spiders have simple eyes, and many mites lack such organs of vision. In connection with what have the eyes of a large number of species of ticks disappeared? How do they manage without them?

Homework - textbook material on the diversity of arachnids, solving additional questions on this topic (Annex 3)

organizational conclusion

Literature:

1. N. F. Bodrova "Studying the course" Zoology ", Grade 7. Voronezh: VSPU. 2000.
2. EN Demyankov, AI Nikishov "Biology. Animal World". Tasks. Additional materials. M., "Vlados", 2004.