The value of arachnids in nature and human life. The value of arachnids in nature and human life: description, photo Why do we need spiders in nature
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Scorpions of scorpions - about 10 cm. The largest of them reach a value of 20 cm. They are united by the presence of claws and a flexible tail in which a poisonous gland is placed. The cephalothorax is covered with a shield on which the eyes are located: five pairs of small ones on the sides, as well as larger ones in the middle. True, they see poorly, they mostly feel with the help of small hairs on their claws. The body of a scorpion is covered with a strong chitinous shell, which consists of a cephalothoracic shield, seven dorsal and abdominal shields and five chitinous rings defending the tail. The scorpion has six pairs of limbs, two of which are jaw organs, the rest are used for locomotion. Habitat
Scorpions prefer countries with a warm climate. They live both in tropical rainforests and in sandy deserts. Representatives of the scorpion family can be found in Australia, Africa, India, southeastern Europe, Asia, North and South America. On the territory of the former USSR, 15 species of scorpions can be found. They mainly live in the countries of Central Asia and in the Crimea. However, sometimes they come across in other regions. Despite their love for the hot desert climate, scorpions are not very adapted to it. They constantly hide in various shelters and burrows, where the air is more humid. There they are better able to endure heat and dryness. Scorpions are nocturnal creatures. And at the same time of day, they hunt for various small animals (crickets, cockroaches, mice, lizards, spiders, etc.)
It is desirable to keep in terrariums. For successful content, you need to remember these things: * Scorpios require a constant change of environment. In principle, it is not so difficult to equip a terrarium (place a few large stones, some snags, small stumps), but do not forget that you need to add something new from time to time, constantly change the situation.
* Do not forget, also, about such things as - humidity and temperature. It is desirable that in different places of the soil, they are different. In one corner there should be a lamp that supplies heat, and in the opposite side a source of moisture (wet cotton wool, wet moss). Sometimes, you can also moisten the soil with water.
* Another important thing is space. Scorpios require a lot of it. For the normal existence of an adult scorpion, the dimensions of the floor must be at least 50x60 cm. Breeding
Most scorpions are viviparous, although there are some species that lay eggs. The female scorpion bears not so many offspring - from 5-6 cubs to several dozen. After birth, the young climb onto the body of the mother and stay there for several days. Here they survive the first molt and become completely independent individuals. In no case should you separate the female and the babies at an early stage, since they are completely dependent on the mother. Immediately after the young leave the mother and begin to crawl on the substrate on their own, they must be separated and kept separately, otherwise they will try to kill each other. Scorpions become adults after 7 molts - this is approximately 1.5 years after birth.
Water is a must for a scorpion. You can spray the plants with a spray bottle and thus moisten the environment. Also, it is recommended to put a low drinking bowl, where the scorpion will crawl from time to time and quench its thirst. Scorpions are unpretentious in food - they absorb almost everything: mealworms, small earthworms, spiders, caterpillars, ants, etc. It is advisable to feed the scorpion in a box, especially for worms that can run away and burrow in the substrate. Larger scorpions can be fed rodents from time to time, but do not overdo it - it can even hurt.
By eating bugs that can destroy crops, spiders serve an important function in many ecosystems. Spiders are also prey to other animals, which further increases their ecological importance, and spider silk is potentially useful for humans as a material.
Spiders are very important in checking insect and arthropod populations, and they are also food for birds, snakes, fish, and other animals, including some that humans eat. In this sense, spiders are an important part of the human food chain. Although many people dislike them, spiders eat insects that could otherwise infect people's homes.
According to Pennsylvania State University, silk silk may prove beneficial to humans due to its durability.
Significance in nature and human life of arachnids: description, photo
If researchers can find a way to make artificial spider silk, it could be used to make everything from artificial tendons to bulletproof vests and parachute cords. Spider silk is described as "tougher than Kevlar and stronger than steel", but it's also very good, making it a very useful substance in a wide variety of situations. Spider silk may also have fewer practical uses; it may one day be used as an alternative source of material for the manufacture of expensive fabrics.
From a spider, the harm to a person is small, but the benefits are great. Few of the spiders are poisonous; these, of course, are dangerous to people who live where there are many poisonous spiders. Spiders that have settled in houses clog the walls of our dwellings with cobwebs. There is no other harm.
And the benefits are great.
The value of arachnids in nature and human life
Spiders are voracious: every day they eat no less than they weigh. When the hunt is especially successful, some spiders from the genus araneus (and among them our usual cross) catch in the net for ... five hundred insects per day. Flies predominate in this catch.
And now let's calculate: in a forest or in a meadow, in a hectare space, that is, in a square of one hundred meters per hundred, there often lives a million (in the Bryansk forests), and in some places (in England, for example) 5 million all kinds of spiders! If each spider from sunrise to sunset catches not 500 (this, apparently, is something about a record), but at least two flies (this is for sure) and let there be a thousand times fewer spiders (an average of 5 thousand per hectare) , then how many of these damned insects die every day on every square meter of our country? One fly is a minimum, and a maximum - in places where there are a lot of spiders - 250 thousand of all kinds of insects, mostly harmful.
But the fly, it only looks harmless. When they recognized her closer and examined her carefully, armed with a microscope, they were horrified. This insect is pure apocalypse! They counted 26 million microbes on the body of a single fly! And such terrible ones, from which people get sick with tuberculosis, anthrax, cholera, typhoid fever, dysentery, various worms. When the summer is hot, one fly produces nine generations of its own kind. And their number is multiplied from each unit to 5,000,000,000,000 flies! By autumn, the entire planet would have been completely littered with flies, and above these stinking blockages, myriads of flies, counted by cosmic figures, would buzz. Mankind, presumably, would all perish. Only the enemies of flies, mainly spiders, save us from such a nightmare.
The conclusion from this simple arithmetic seems to be clear: watch out for spiders! Maybe a lot of them are unsympathetic. Perhaps the human aesthetic sense finds its satisfaction in completely different living forms. Maybe ... But the intellect of a person is always the first dominant, and therefore everyone should remember: a spider is a friend to a person!
Spiders are good for us already because they destroy flies. What else are they good for?
An amazing web. And, alas, in our utilitarian age we do not dispose of it. Looking at the spider, the primitive man learned, perhaps, to spin. And if he didn't (looking at the spider!), then it's not the spider's fault, which sets a great example here. One way or another, the method was mastered, and the material for yarn began to be searched here and there: they spun the ancient fine linen from the byssus threads of sea mollusks, spun it from the wool of goats, rams and camels. And then, suddenly, an unexpected discovery happened: one summer day, the Chinese Empress pulled the cobweb of a silkworm caterpillar that had fallen into a cup of tea with her sharpened nails - and the cobweb kept stretching and stretching! Those caterpillars were bred, tamed and surprised the world with the brilliance of precious silk.
But what is their silk compared to that with which the spiders fill our forests in prodigal abundance.
There were such experiences. This practice still exists.
"Satin of the East Sea" - tong-hai-tuan-tse, a once very durable fabric, was apparently spun from the web of not caterpillars, but spiders.
They say that in March 1665, the meadows and fences near Merseburg were covered with a great many webs of some kind of spiders, and from it "the women of the surrounding villages made themselves ribbons and various ornaments."
And later, Louis XIV, King of France, was presented with stockings and gloves woven from silky threads of French spiders by the Parliament of Montpellier. Magnificent web gloves were sent to Josephine, Napoleon's beloved, by Creoles from the island of Mauritius.
At the same time, more than a hundred years ago, the famous naturalist D'Orbigny sported pantaloons from the web of Brazilian spiders. He wore them for a long time, but they did not wear out. D'Orbigny wore them to a meeting of the French Academy. But the French Academy was not surprised by the pantaloons made of cobwebs: it had already seen such curiosities and even discussed the question of whether it was worth recommending the weaving industry as a yarn for silk.
Someone Bon, "President of the Chamber of Accounts in Montpellier", 260 years ago presented a paper to the Academy of Sciences in Paris. In it, on many pages, he described the basics of spinning and making fabrics from cobwebs, and attached two pairs of visual aids to the report: stockings and gloves.
The Academy elected a commission, which was charged with studying in detail the reality and profitability of spider sericulture and silk weaving. Reaumur, a member of this commission, found the web quite suitable raw material for industrial production, but decided that the local, French spiders did not weave threads of the required length. He calculated that it would take 522-663 spiders to process one pound of spider silk, and industrial production would require hordes of spiders and clouds of flies to feed them - more than they fly over all of France.
“However, perhaps in time it will be possible to find spiders that give more silk than those that are usually found in our state” (Rene Antoine Réaumur).
Such spiders were soon indeed found in the tropics. Travelers used to say that birds get tangled in their web! A pith helmet hangs on it - and it does not tear! So strong are the web threads. And one spider in a month easily pulls out three or four kilometers of such threads.
These amazing spiders were called nephiles. Nature did not stint either on colors or on the talents necessary for weavers, and generously endowed the nephil with them.
A spider of the Madagascar nephila, with a golden chest and fiery red legs in black "socks", spins a cobweb sparkling with gold. Huge (together with her legs - the size of a thumb), she, like a giant queen, rests on a carpet woven from golden "wool", surrounded by nondescript male dwarfs (the female weighs five grams, and her husband is a thousand times less - 4-7 milligrams!).
Our compatriot, the famous Miklouho-Maclay, was the first European to see and describe the very useful use of the web by people in New Guinea. It is so unusual that many people met stories about it with great disbelief. A quarter of a century after the death of Miklouho-Maclay, the collector of the British Museum of Natural History A. Pratt came with his son to the same New Guinean forests and lived there for two years. And this is what he said when he returned to Europe in 1904:
“There are many cobwebs of huge spiders in the forest, it is six feet in diameter. Woven in large meshes - about an inch at the edge of the web and one-eighth of it in the center. The web is very strong, and, of course, the natives quickly figured out how to profitably use it in business, forcing a large, hazelnut-sized hairy spider to serve a person.
They bend a large rod of bamboo in a loop and put it close to the web. “Very soon, the spider will braid this convenient frame” - and a great net is ready!
In the backwaters of the river, where small whirlpools are circling the calm current, they catch fish with this net: they pick it up from below and throw it ashore. "Neither water nor fish can break the mesh" - so strong.
Alas, few believed Pratt that fish were caught with cobwebs in New Guinea. But later, other researchers saw this with their own eyes in New Guinea, Fiji, the Solomon Islands and other islands. A lot has already been written about this in new books and articles. They say that even butterflies, beetles, small birds and bats are caught by enterprising children of the forests with cobweb nets. And the fish seem to be pulled out of the water weighing a pound and two!
They also came up with another way of fishing with cobwebs. They bend a rod with a hoop, braid it with a cobweb of nefil, put bait on top - ants and their eggs - and let this set tropical pattern net go with the flow. Small fish peck the bait from below, from the water, and get tangled in the web with their gills. Down the river, hoops with a catch from the water are selected. Two or three of these floating nets can catch a dozen fish in a quarter of an hour.
Recently, finally and experimentally, the strength of the nephil web was tested. A thread one-tenth of a millimeter thick can withstand 80 grams (silkworm thread - only 4-15 grams). It is so elastic that it stretches almost a quarter of its length and does not tear. A meter-long thread of a silkworm is pulled out without breaking only 8-18 millimeters.
The fabric of golden nephila web is surprisingly airy and light; with the same strength, it is much thinner than silkworm silk, and with the same thickness, it is much stronger. Cobwebs for yarn are collected from nephil nets or their egg cocoons are unwound. But it is better to pull it directly from the spider, which is put in a box - only the tip of its abdomen with spider webs sticks out of it. Elastic threads are pulled out of warts “just like a cocoon is unwound,” says J. Rostand, a great expert on sericulture. “In this way, from one spider you can get about four thousand meters of silk thread in a month.” The thread untangled from the cocoon of a silkworm, depending on its breed, is from three hundred to three thousand meters long.
Using different methods, experimenters obtained, for example, threads of this length from different spiders: 1) in two hours from 22 spiders - 5 kilometers, 2) in a few hours from one spider - 450 and 675 meters, 3) in nine "unwindings" of one spider in within 27 days - 3060 meters.
The best results were achieved by Abbé Kambue, exploring the silkworm possibilities of the Madagascar galaba spider. In the end, this inventive man managed to improve his business so much that he “connected” living spiders in small drawers directly to a special type of weaving loom. The loom pulled threads from spiders and immediately wove the finest silk from them.
They tried to acclimatize Galaba spiders at one time in France and here in Russia. But nothing came of it.
A web, even a nephil, will hardly ever enter wide production: it is not easy to maintain farms of silkworm spiders - how to feed them? Therefore, gossamer fabrics are 12-14 times more expensive than silk made from caterpillar cocoons. But for some special purposes, strong and light web yarn can be very useful. For example, for airships, which, it seems, will soon be built again. Seventy years ago, they already tried to weave a shell for airships from a web of nephil, “and it was possible,” says Professor A.V. Ivanov, “to make a sample of luxurious silk fabric 5 meters long.”
In optics and instrumentation, gossamer threads have already found application.
The benefits of spiders To a man from a spider, the harm is small, but the benefits are great. Few of the spiders are poisonous; these, of course, are dangerous to people who live where there are many poisonous spiders. Spiders that have settled in houses clog the walls of our dwellings with cobwebs. There is no other harm. And the benefits are great. Spiders are voracious: every day they eat no less than they weigh. When the hunt is especially successful, some spiders from the genus araneus (and among them our usual cross) catch in the net for ... five hundred insects per day. Flies predominate in this catch. And now let's calculate: in a forest or in a meadow, in a hectare space, that is, in a square of one hundred meters per hundred, there often lives a million (in the Bryansk forests), and in some places (in England, for example) five million all kinds of spiders! If each spider catches not five hundred from sunrise to sunset (this, apparently, is something about a record), but at least two flies (that's for sure) and let there be a thousand times fewer spiders (an average of five thousand per hectare) , then how many of these damned insects die every day on every square meter of our country? One fly minimum, and maximum - in places where there are a lot of spiders - two hundred and fifty thousand all sorts of insects. Mostly harmful 6. But the fly, it is only seemingly harmless. When they recognized her closer and examined her carefully, armed with a microscope, they were horrified. This insect is pure apocalypse! They counted 26 million microbes on the body of a single fly! And such terrible ones, from which people get sick with tuberculosis, anthrax, cholera, typhoid fever, dysentery, various worms. When the summer is hot, one fly will produce nine generations of its kind. And their number will increase from each unit to 5,000,000,000,000 flies! By autumn, the entire planet would have been completely littered with flies, and above these stinking blockages, myriads of flies, counted by cosmic figures, would buzz. Mankind, presumably, would all perish. Only the enemies of flies, mainly spiders, save us from such a nightmare. The conclusion from this simple arithmetic seems to be clear: watch out for spiders!
1. Representatives of scorpions, their habitat, food, reproduction ...
Maybe a lot of them are unsympathetic. Perhaps the human aesthetic sense finds its satisfaction in completely different living forms. Maybe ... But the intellect of a person is always the first dominant, and therefore everyone should remember: a spider is a friend to man!
So that the flies do not forget how to fly :))
To eat flies! So them, so them!
They say there is such a tradition, if a spider came to the house, then expect good news. You can't kill them!!!
Why are people needed? Spiders at least don't destroy this planet.
To limit the fly population.
To scare those who are afraid of them..
so that flies and other insects do not get people))! And tarantulas do eat birds! kill the spider, kill your happiness! (I came up with this myself!)
Millions of insects live on our planet, and all of them play a big role in the life of the environment. Arachnophobes will be quite surprised that arachnids are an important part of human life.
Many are thoughtlessly exterminating spiders, scorpions, but why did nature actually create such terrible-looking creatures?
Why were arachnids created?
The importance of arachnids in nature and human life is quite large: they bring many benefits to people and at the same time can be carriers of dangerous diseases. Playing the role of predatory creatures, they kill insects, at the same time being part of the food chain in various animals, birds, and aquatic inhabitants. In nature, they perform the work of creating a habitat for other creatures, for example, the process of soil formation cannot do without soil mites.
In agricultural activities, an ambulance comes from arachnids to combat pests that spoil seedlings in the fields and in the forest belt. This is an important feature of the importance of arachnids in nature and human life. Sometimes special predatory mites are placed indoors to conduct a biological rescue operation.
Spiders: what is the use of them
As you know, the spider web is of great benefit, for example, to catch up to four hundred insects, one spider will need only a day. Incredible, right? This means that all cobwebs on garden trees or fences, as well as shrubs, vegetable gardens, vineyards, are of great benefit for cleaning off harmful insects. Since predatory animals appear in small numbers in spring, it is the best time for spiders to breed. Spiders are quite resistant to cold weather, so their work can last continuously all year round.
For a person, harm from a spider occurs when it braids home walls with its nets, of course, this does not look attractive at all. And the spiders themselves are not very beautiful, and some people are so scared that they develop a phobia. You need to be afraid of spiders, living in the area where they are poisonous.
The catch of a spider is usually flies, so if you are overcome by these annoying flying insects, then in no case drive out all the spiders, leave at least one. In a day, a spider can eat about as much as it weighs.
Scorpions: Should You Be Afraid of Them?
Don't be surprised that scorpions are also arachnids. Scientists have determined that this is the most ancient order of arthropods on planet Earth. Today, there are about one and a half thousand different species. The Himalayan heights and caves that go as deep as 900 meters are the home of scorpions, they live in the tropical jungle, in the forests of Europe and even on the seashore.
The largest species of scorpion is the imperial scorpion, whose representative can grow up to 20 cm in length.
The value of arachnids in nature and human life is great, even if we do not see a direct benefit. Scorpions are dangerous and quite ferocious, they are especially active at night in the heat, their body picks up any fluctuation of the wind. Thanks to sensitive receptors, they can feel the touch of their future prey on the sand from a distance of about 30 cm.
If it suddenly turned out that the proposed dinner did not suit him, the scorpion takes a belligerent position to scare away the failed victim. But when the creature satisfies the scorpion, it grabs it with its claws and beats it with its sting in a big way. To do this, its tail acquires an arc-like structure. The value in nature and human life of the arachnid scorpion is determined as part of the food chain.
It does not help a person get rid of garden pests, but supports the theory of natural selection on the planet. After the poison enters the body, it is paralyzed and all organs gradually cease to function.
Scorpions are individual farmers, they will never share their prey, and even in too difficult conditions, if a brother is nearby, they can kill him and eat him. Despite this, these arachnid creatures can keep the body starving for up to two years, including the lack of water. But they eat up quickly, having washed the bloodworms on both cheeks, they can continue to walk around full for several months.
The rumor that there are non-venomous scorpions is false. Absolutely all individuals secrete poison, just the degree of toxicity is different for each. When a person bites, the poison immediately seeps into the bloodstream, through which it reaches the nervous system, while simultaneously polluting the entire body with strong toxins. In fact, only twenty-five species are dangerous to humans. The most poisonous is the species that lives mainly in North Africa. For example, in Tunisia. It is called Palestinian, and about 90 percent of the people whose bodies have been poisoned die from its bite. By the way, the life expectancy of such an arachnid is up to twenty-five years.
The life of pests in the human environment
Ticks are also of great importance in nature and human life, but rather negative. Spider-like small pests are most often the cause of a particular disease. With the help of a tick, a person receives a pathogen, and that, in turn, is provided with good nutrition in the form of human blood. The most famous ticks are taiga and dog species. The first spreads encephalitis, and the second tularemia and hemorrhagic fever.
Spiders are among the most important entomophages, exterminating a huge number of insects and limiting the increase in the number of some harmful species.
In addition, spiders themselves serve as food for many animals (see "Relationship with other animals. Enemies. Ways of protection.")
There are not so many spiders that are dangerous to humans compared to the total number of their species. Venomous spiders are found among various families, but they are most abundantly represented in the family Theraphosidae from South and Central America. On the other hand, spiders that are dangerous to humans have not been found at all among such families as Gnaphosidae, Linyphiidae, Micryphantidae and in the entire Cribellatae group. It should be added that in the north and in the middle lane there are no poisonous spiders at all. Spider venom acts like strychnine, although weaker - first excitement, then breakdown and paralysis. This is a complex biochemical mixture: it contains both neurotoxic, paralyzing the nervous system, and hemolytic, blood-destroying substances. According to the nature of the poisoning caused, poisonous spiders are divided into two groups: the bite of some causes local pathological reactions, the poison of others has a neurotoxic effect on the entire animal or human body. The bite of the latter, as a rule, causes severe pain and leads to very serious consequences, and sometimes death.
Experiments have shown that the poisonousness of spiders, in particular tarantulas, is highly variable and depends on the season, sex, age, race of the spider and the environment in which the bite was made, and even on whether the spider was crushed when it bit. It was found that the most poisonous females of a large race, in the summer, during the mating season. Perhaps the poisonousness of spiders varies depending on the geographical latitude of the area and that it is stronger in the south than in the north. But in general, despite the large number of rumors about the strong toxicity of the tarantula, there have been no official deaths from their bites. I must say that the bite of some non-dangerous large spiders that can bite through human skin can also cause unpleasant painful phenomena. For example, the bite of a female Eresus niger from Cribellatae, which is widespread in the steppe and semi-steppe zones of the former USSR, causes acute pain, quickly replaced by numbness.
The veterinary significance of the same tarantula is unclear. There is an opinion about its strong toxicity to cows. It is believed that a cow that has eaten a tarantula dies.
But spiders are much more useful. And medicine has been dealing with them for a long time. For example, the web as a plaster for wounds is used in folk medicine. Indeed, clean, fresh cobwebs have been proven to have bactericidal properties. In addition, healers use the web to treat alcoholism, but this property has not yet received scientific confirmation.
And before the discovery of America, before cinchona was found, even malaria pills were made from spiders.
But the biggest role for humans, as well as for the entire planet, is played by the gluttony of spiders and the destruction of harmful insects by them, and Stegodyphusmimosarum spiders are even bred in South Africa to fight houseflies. Spiders destroy a huge number of arthropods of medical importance - bloodsuckers and carriers of pathogens of infectious diseases. The role of spiders in the extermination of the malarial mosquito is especially great.
It must be said that biological methods for the protection of agrocenoses using spiders were also proposed. They exterminate harmful insects, and, according to some researchers, various entomophages (taken together) destroy fewer insects than spiders. Thus, by creating favorable conditions for the life of spiders, it would be possible to protect agrocenoses in an environmentally safe manner. Unfortunately, this method is not used anywhere on a large scale. (Kharchenko L.N., 1997)
In addition, we must not forget about the wonderful web. There were even attempts to spin fabric from it, which turned out to be very thin, light and much stronger than silk. True, such a fabric will hardly ever enter wide production: it is not easy to maintain spider farms because of their great voracity. There have also been attempts to use spider silk for airships. But in the optical industry (for the preparation of crosshairs in telescopes, microscopes, optical sights of rifles), the web has already found its application. In addition, especially strong and lightweight compounds are made from the web - composites. Bulletproof vests made with the addition of webs are used in Germany, the USA and other countries. The program for the study of the structure and artificial synthesis of the web is funded by the US military. Similar developments are underway in our country. (Mikhailov, 1994)
In addition, the fact was established that spiders carry, without any visible changes in the body, a level of radioactivity thousands of times higher than the human lethal dose. It is obvious that such a phenomenal ability of spiders needs to be studied in depth. (Kharchenko, 2000)
It must be added that a person also has an influence on the spider, and by no means positive. Thus, the analysis of group diversity showed that in urbanized areas there is an impoverishment of the species composition of the spider fauna and its structural restructuring. In areas of residential complexes, as a rule, there are few web spiders, since the high dust content of the air makes it difficult to use spider traps. In general, the fairly sensitive response of spiders to changes taking place in urbanized areas affects the ratio of life forms in the community and the change in dominant groups. (Lukyantsev, 1999)
Spiders are the most numerous order of arachnids, inhabiting almost the entire planet, with the exception of areas forever covered with snow.
Spiders have occupied all habitats, however, among the representatives weaving trapping nets, there are only terrestrial forms, some of which can swim or settle through the air.
Spiders are the most important entomophages, playing one of the main roles in regulating the number of insects on the planet.
Guided by a complex chain of instincts, they have a rather complex and interesting behavior to observe, taking care of their offspring to some extent and changing their behavior during the mating season.
The main distinguishing feature of spiders, which is peculiar only to them, is the ability to weave a web, which serves them both for building dwellings, and for breeding, and for hunting. The ability to weave a net is genetically incorporated, their shape, size and number of threads are specific for each family.
Most spiders live alone, with hostility towards other related individuals.
As it turns out, the subconscious fear of spiders, arachnophobia, is groundless for many people: there are very few species dangerous to humans compared to the total number, much more, both for humans and for all of nature. Spiders are useful.
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.
- Find features of adaptability in the external structure of the cross-spider to the terrestrial lifestyle.
- In the internal structure of the spider, highlight the features that distinguish it from cancer. Why are spider and crayfish classified as the same type?
- 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
Creating a problem situation and setting 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 times, 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 in almost all inhabited latitudes and altitudes: 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!".
It 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 a lancelet 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"
Tick is a 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 with vegetable oil, wait 30 minutes, grab it with tweezers and gloved fingers, as close to the skin, and slowly pull it out. If the head of the tick remains, then treat this place with iodine or alcohol and rinse twice a day with warm water until it is completely healed.
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"
In appearance, they could be mistaken for cancer, the resemblance between them is only external: the scorpion has no antennae, its head limbs are not armed with claws, it breathes with the help of lung sacs and the total number of limbs is 8. The structural features of scorpions are jointed abdomen, the posterior 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. A 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 output
Literature:
- N. F. Bodrova "Studying the course" Zoology ", Grade 7. Voronezh: VSPU. 2000.
- EN Demyankov, AI Nikishov "Biology. Animal World". Tasks. Additional materials. M., "Vlados", 2004.
Scorpion is a very interesting and unusual creature that leads an exclusively terrestrial lifestyle in areas with a hot climate. Many often in relation to him may have questions such as: scorpion is an insect or animal where does it live, what does it eat and how does it reproduce. We will answer them in our article.
Features and habitat of the scorpion
Scorpion belongs to animals order of arthropods and class arachnids. It is distinguished by its rather intimidating appearance and speed of movement, and females and males are similar in appearance.
AT description appearance scorpion it should be noted that its body consists of a cephalothorax and an elongated segmented abdomen. The cephalothorax has a trapezoidal shape, on which there are pincers of impressive size, which serve to grab prey.
Also in the lower part of this part of the body (near the mouth) there is a pair of tentacles, which have become rudiments, performing the function of the jaw organs - the mandibles. The abdomen, in turn, contains outgrowths and four pairs of legs.
These outgrowths, with the help of the hairs on them, are the organs of touch. Various vibrations are captured by the hairs, which provide the animal with information about the terrain or the approach of the victim.
The limbs are attached to the bottom of the abdomen and allow the creature to develop very high speed when moving through areas with obstacles, in the form of quicksand in the desert or stones in the mountains.
The last segment of this part of the body of the scorpion ends in a relatively small pear-shaped segment-capsule containing glands that produce poison. At the end of this capsule is a sharp needle, with which this creature injects poison into the body of the victim.
The body of a scorpion is covered with a very strong chitinous shell, so it has almost no enemies that can harm it. In addition, it contains a substance that can glow when exposed to ultraviolet rays.
Depending on the habitat conditions, these creatures have a different color of the chitinous cover. So, there are sandy-yellow, brown, black, gray, purple, orange, green and even colorless scorpions.
The creature has rather poor eyesight, although it has many eyes. So, in the upper part of the cephalothorax there are 2–8 organs of vision, and two of them are larger and are called median.
The rest are located on the sides of the front edge of this part of the body and are called lateral. The lack of sight is fully compensated by the sense of touch, which is very sharp.
In nature, there are several types of scorpions, which differ in their size, color, habitat and life expectancy. They are imperial, arboreal, desert hairy, black and yellow fat-tailed and stripetdal.
The habitat of the scorpion is very wide, it can be found on almost all land areas with the exception of some areas of the Arctic, Antarctica and the New Zealand Islands, however, it prefers warm, arid regions, therefore it is often called scorpion desert animals.
The nature and lifestyle of a scorpion
Since this animal lives in arid zones, it is distinguished by its endurance to environmental conditions. He very easily tolerates heat, cold, hunger and even radiation.
To reduce body temperature, depending on the terrain, he buries himself in the ground or hides in stones, or cools himself in an interesting way, which consists in taking a stance, characterized by the fact that he straightens his legs to prevent contact of the body with the ground. This position allows free circulation of air, which cools the creature's body from all sides.
Important for life in such zones is the ability of the scorpion to go without liquid for several months. He easily makes up for her lack with the help of his victims. However, when the opportunity arises, he likes to drink water and bathe in dew.
Also, due to the special structure of the digestive system, the scorpion does not need regular nutrition. Although scorpion enough dangerous animal however, it has a peaceful character. When a person approaches, the creature prefers to take cover in nearby shelters, attacking only in extreme cases.
The creature hunts at night, learning about the approach of prey by the vibration caught by the hairs. In preparation for the attack, he takes a threatening posture, characterized by bending the tail and waving it in different directions. Scorpion mostly leads a solitary lifestyle, very rarely when they gather in groups, so he finds his mate by a lucky chance.
Scorpion food
Which same animal scorpion in terms of nutrition? The scorpion is a predator. His main food is insects (, centipedes,), however, he does not disdain small rodents, and there are frequent cases of "cannibalism" in which weaker relatives are eaten.
During the hunt, the creature grabs prey with the help of pincers and pricks with a poisonous sting, first paralyzes it, and then kills it. As mentioned earlier, the creature does not feed every day.
Reproduction and lifespan of a scorpion
Having found a female, the male does not immediately mate with her. The couple preliminarily goes through the mating season, accompanied by the performance of the "wedding" dance by the scorpions, the duration of which takes hours. In time, the male, holding the female with the help of claws, moves her back and forth on the soil moistened with his sperm and periodically lowers it onto her.
After mating, in which the female often eats the male, she becomes pregnant, which lasts 10–12 months. Since the scorpion is a viviparous animal, this act of cannibalism provides a large number of nutrients necessary for producing strong offspring.
After this period, cubs appear, the number of which, depending on the variety, ranges from 20 to 40 pcs. For the first two weeks, babies do not have a chitinous shell, so they are all the time on the back of the female, clinging tightly to each other.
Pictured is a scorpion with cubs on its back
As soon as the shell is formed, the cubs leave the mother and scatter around the nearby territory for independent existence. To an adult, they grow only after a seven-fold molt.
The scorpion has a rather long life span, which under natural conditions can reach 7–13 years, however, in captivity, which they do not tolerate well, it is significantly reduced.
What to do with a scorpion sting?
For a person, a scorpion sting in most cases is not fatal, it mainly causes discomfort, accompanying such manifestations as sharp pain, swelling and redness of the skin around the wound. However, the poison of some species of these animals can be fatal.
Since not each of us can identify which scorpion has bitten - dangerous or non-dangerous, it is necessary to immediately provide first aid. To do this, you need to try to squeeze out or suck out the poison.
Treat the wound with antiseptic drugs, apply cold or apply a tight bandage that can slow the spread of the poison. Apply antiallergic agents. After giving first aid, be sure to take the victim to the hospital.
Despite the fact that the scorpion is quite dangerous, people have been interested in it since ancient times. Nowadays, it is increasingly possible to see it in people's homes, and it is also the main attribute in magic and witchcraft.