Ecosystem of plants and animals. Forms of relationships between plants Communication between plants and animals of swamps examples

Contrary to the epigraph given by us, we know that in no corner of the globe there are plants, animals, microorganisms living alone. Plants have many friends, but also many enemies besides fungi and bacteria. Insects play a very important role, sometimes useful, and sometimes extremely harmful, in the life of plants. In the course of the development of the living world, over millions of years, various, sometimes very complex, relationships have developed between plants and insects. Suffice it to recall the role of insects in the so-called cross-pollination of plants, the importance of plants for the life of bees; Let's also remember insects - pests of forests, vegetable gardens, orchards.

In the forest, in the meadow, in the swamp, in the seas - everywhere in nature the life of plants and insects is interconnected and in some respects represents, as it were, one whole. Science, accumulating more and more facts about plants and animals, at the same time studies patterns in the life of plant and animal communities.

In lakes, rivers, coniferous forests, oak groves, bird cherry thickets, on citrus plantations - everywhere there are their own, peculiar relationships between plants and animals, their animal population prevails, confined only to certain types of plants, a certain nature of the soil, etc. . The female carrion flies lay their eggs in rotting plant and animal products. Fly embryos can develop among swarming microbes. An egg that has left the body of a fish can be in the vicinity of various microbes, plants and animals.

Each type of forest has its own animal organisms. In beech forests, there are from 3 to 4 thousand plant species and from 6 to 7 thousand animal species (microscopic unicellular animals are not taken into account here). It turns out that a significant part of the animals is strictly confined to beech forests. About 1800 species of animals and 1170 species of plants find favorable conditions for life only in beech forests.

Let's take an example. It is unpleasant, but perhaps useful, as it will make you wash fruits and vegetables more thoroughly before eating them. In the wonderful Peterhof park near Leningrad, scientists have calculated how many different insects and mites can be, for example, on a berry. On 400 grams of strawberries there were about 600 specimens, mainly mites, on 400 grams of blueberries - about 1100, on the same amount of raspberries - 5000, mountain ash - more than 7000. And in the crown of one large birch there are about 5-10 million.

And here is another no less peculiar case of the relationship of organisms in nature based on the release of phytoncides. Scientists for a long time could not understand how the blood sucked by a leech becomes food for it. Alien blood with its complex chemicals must first change, and then in a simpler form it can be absorbed by leech cells. In animals and humans, special substances are produced in the intestinal tract - enzymes, due to which digestion occurs. In the intestines of leeches, these substances are not present. What turned out? In the intestines of leeches, the bacterium Pseudomonas hirudinis constantly lives, multiplying strongly. This bacterium is beneficial to the leech. She helps to digest the sucked blood, releasing the appropriate substances, and she, releasing her phytoncides, which are deadly for other microbes, turns out to be the only sovereign mistress in the intestines of leeches and does not allow any other bacterial contamination. That is why the intestines of a leech are completely clean, from a blood-sucking leech you will never get a contagious disease. No wonder scientific medicine uses leeches in the treatment of many diseases.

Man, being a part of nature, became its creator, the most important factor in its evolution. In carrying out gigantic construction, the socialist state must also foresee the biological consequences: what plant communities will be formed when certain tree species are planted, how will the animal and plant world change when new canals are built, how will the life of reservoirs change? Biologists of all specialties, participating in these magnificent affairs, are also busy solving the problems that arise.

All new discoveries in the relationship between animals and plants are used in the interests of man, put at the service of the forest industry (medicine, agriculture, horticulture, horticulture. I would like to think that in the coming years it will be possible to extract something from the discovery of phytoncides, useful not only for fight against bacteria, protozoa and fungi, but also to regulate the life of plant communities and higher animals, as well as actively use phytoncides to preserve human health.

But back to the relationship between phytoncides and insects.

The thought involuntarily arises whether phytoncides also play any role in the confinement of certain insect species to certain plants and plant communities? Do volatile phytoncides have any significance in nature as repellent or, conversely, insect-attracting substances? Is it possible to use phytoncides in everyday life and medicine as insecticides - substances that kill harmful insects? Is it possible to scientifically explain folk plant remedies for combating harmful insects? This area of ​​research is so tempting because it is of great practical importance.

Let's report some facts. Perhaps they will awaken readers' interest in observations and experiments in nature.

Let's take a short excursion into the past and report on one discovery that happened back in 1928-1930. This discovery subsequently convinced us of the usefulness of studying the effect of phytoncides on multicellular animals, in particular insects.

Already in the first days of the discovery of phytoncides, when it was clear that the volatile substances of some plants act detrimentally on fungi, the question arose: are we dealing with poisons that are harmful to the protoplasm of certain cells, or with poisons for any protoplasm? Now we know well that phytoncides act selectively: they kill some cells and organisms and do not kill, but even stimulate others.

One of the first experiments on phytoncides were experiments with mollusk eggs - with those cells from which the development of these organisms begins. There are a lot of mollusks, "slugs", in the seas, fresh water bodies and on land (Fig. 21).

Aquatic mollusks lay their eggs on the leaves and stems of plants, on stones and other hard objects. Each time they are deposited several dozen. All of them are in a common transparent gelatinous mass, which plays an important role in protecting the embryos from external adverse influences. Each egg, in turn, is dressed in shells. These shells are so transparent that through them with a magnifying glass it is easy to observe all the successive stages of the development of the embryo up to the formation of a microscopic mollusk, in which the shell is already clearly visible. Freed from the shells, the mollusk begins to lead an independent existence as an adult animal.

Microscopic embryos of mollusks are defenseless in appearance. But this impression is erroneous. The shells of eggs have such a structure and composition that many substances that are poisonous for more complexly organized animals are completely harmless to mollusk eggs. It is, of course, easy to crush a mollusk egg, it is possible to kill an egg with high temperature, but it is not easy for a scientist to select chemical poisons for these delicate, elegant, transparent cells, since many substances poisonous to protoplasm do not penetrate the egg shell.

Let us take one oviposition of a mollusk at such a stage of development when the movement of embryos can be seen through transparent shells. Let's cut this egg-laying into two halves. We use one half for the experiment, and the other will remain the control.

We place the experimental half of the egg-laying in a drop of water on the glass, and next to it we put the onion gruel just cooked on a grater. In the very first seconds (usually no later than 30 seconds), we will notice a sharp acceleration in the movement of the nuclei: they come to an excited state. After a minute or two, this state is replaced by a complete stop of movement. Some time will pass, and we will see, with the apparent preservation of the egg shells, the complete decay of the embryos. The eggs of the control half of the oviposition, which are also in the water, develop perfectly.

Very many plants have such properties, for example, leaves, buds, bird cherry bark (Fig. 22), horseradish rhizomes, leaves of cherry laurel, maple, oak, fir needles, etc. Of particular biological interest for understanding the relationships in the nature of plants and animals is the effect of phytoncides of aquatic plants on the eggs of mollusks, frogs, fish and other organisms. Already initial studies have yielded unexpected results. Some aquatic and coastal aquatic plants (certain blue-green algae, spirogyra, manna) inhibit the development of mollusk embryos, while others stimulate it.

And again the thought arises: is this phenomenon not accidental? Are the discovered facts related to the protective properties of aquatic plants? Does it matter to plants if molluscs and other aquatic animals lay their eggs on them? Does it matter to mollusks on which plants to lay their eggs? Thus, we approach the question of the biological self-purification of water bodies, the question of whether phytoncides of aquatic plants play some role in regulating the composition of the animal, plant, and microbial populations of water bodies. We will focus on these issues later.

Ecosystem - a system of life of various organisms. This broad concept includes both the habitat and the system of connections and ways of survival of all creatures.

The role of plants in the ecosystem

Plants play a huge role in any ecosystem. They are an essential link in any food chain. Saturated during their growth with the energy of sunlight, they transfer it to other species of the animal and plant world. For example, a herbivore feeds on energy-rich plants, but serves as food for predatory representatives. Therefore, the disappearance of any vegetation will adversely affect all living representatives.

In addition, it is plants that release the oxygen necessary for life and rid the world of carbon dioxide. The oxygen produced by plants protects the planet from ultraviolet rays.

Plants also play a big role in the formation of the climate anywhere in the world.

Do not forget that it is plants that serve as a refuge for many representatives of the animal world, fungi, lichens. They are ecosystems for some organisms.

The plant world is a fundamental link in soil formation, landscape change and the circulation of mineral substances.

Man is one of the consumers of products produced by plants. People need fresh air, oxygen, food, and without flora, this cannot be obtained.

The flora of our planet is extremely important for humanity. Plants are our food and medicine. Without the plant world, a person would not be able to engage in agricultural activities. The world economy also could not exist without them, because it is plants that are the cause of the appearance of coal, oil, peat and gas.

The role of animals in the ecosystem

Animals, like plants, are an important part of the nutrient cycle. In addition to consuming vegetation or preying on herbivores to create a food chain, many are natural orderlies - consuming dead organic matter.

Predatory animals play a huge role in various ecosystems. Thanks to them, there is a certain balance of populations of all species of the animal world on the planet.

Herbivores are also important for all ecosystems of the planet - they are responsible for the density of plant populations, rid the world of harmful and weed plants.

Many animals carry pollen and seeds - insects, birds and mammals.

Thanks to animals that have a hard skeleton, we can use various sedimentary rocks - chalk, limestone, silica and others.

For the human ecosystem, animals are also important. First, they are the main source of food. Secondly, people use animal materials for tailoring, furniture and necessary things.

Some animals are used by humans as a way to get rid of pests. As a rule, pests are also destroyed by chemical means, while a person does not think about the consequences of the large-scale destruction of certain species of living beings. After all, each species is important for the surrounding world, even if it brings a lot of trouble.

The relationship of plants and animals

The interrelation of plants and animals is very great. As mentioned above, these ecosystems cannot exist without each other, because they are the regulators of the populations of both worlds.

This connection began to form at the moment of the appearance of all life on the planet, which is why it is impossible to imagine nature without one of these links.

In order to understand exactly what the relationship between plants and animals is, we can analyze just a few examples. For example, ants live inside a tree, and in return protect this plant from harmful individuals. And winged insects carry pollen, in return receiving food. Birds protect trees from caterpillars destroying trunks, while also receiving food supplies.

The relationship from the plant world is also simple - plants produce oxygen, without which all living things simply could not exist.

Symbiosis and its forms. Each plant does not live in isolation, but interacting with other plants, bacteria, fungi, animals. Relationships between organisms of different species living together are very diverse: they can benefit all organisms or only one of them, have negative consequences for some of them. All forms of relationships between organisms of different species are called symbiosis (from the Greek sim - together and bios).

Mutually beneficial relationships exist, for example, between the roots of higher plants and the mycelium of cap mushrooms (birch and boletus, aspen and boletus), legumes and nitrogen-fixing nodule bacteria.

Individuals of the same or different species can compete with each other for environmental resources - water, light, nutrients, habitats. At the same time, the consumption of certain resources by some organisms reduces their availability to others. Such relationships between organisms are called competition (from Latin competition - to collide).

An example of competition between individuals of the same species, that is, intraspecific, can be a pine forest, in which all trees are of the same age and compete for light. The faster growing trees shade the stunted ones, further delaying their growth or even causing death. Interspecific competition is observed between species of the same community with similar requirements for habitat conditions. (For example, in mixed forests between oak and hornbeam.)

Plants of different species can adversely affect each other with the help of biologically active substances that they form and release into the soil, water, and atmosphere. Such substances inhibit the growth and even cause the death of other organisms, including plants.

Some species of plants, such as orchids, settle on the trunks and branches of tropical trees without harming them. They use the trees only as a place to settle. Such plants absorb water from moist air with the help of aerial roots, minerals - from dust accumulating in the cracks of trees.

Many animals feed on the tissues of living plants (different types of mites, insects, rodents). Such species are called herbivores. In pastures, animals eat only certain types of plants, avoiding poisonous or bitter-tasting ones. As a protection against eating, nettle leaves have hairs with a burning substance, which, if it enters the skin of animals or humans, causes burns. In many species, leaves (cacti), stipules (white acacia), shoots (hawthorn) are modified into thorns, or special outgrowths are formed on the stem - spikes (rose hips) to protect against animals.

But, as you know, sometimes plants can also feed on animals (various insects and crustaceans). Such plants, such as sundew, kill and digest prey, obtaining additional nitrogen-containing compounds.

An interesting representative of carnivorous plants is vesicular Aldrovanda, floating near the surface of the water. The leaves of this plant consist of two flaps that, when an aquatic insect or small crustacean gets on them, close. Trapping leaves of Nepenthes - an inhabitant of the tropical forests of Asia - look like a deep jug with a lid. When an insect, attracted by the smell, sits on the edge of such a jug, the lid closes and the victim enters its cavity filled with a solution of digestive juices.

The role of animals in the reproduction and distribution of plants. Not only animals in their life depend on plants, but plants often cannot exist without relationships with animals. Insects, some small birds and bats pollinate flowering plants. Therefore, seed reproduction of many species of flowering plants would be impossible without the participation of animals.

Pollinating animals feed on pollen and nectar and have the appropriate adaptations for this. So, some insects (bees, bumblebees), feeding their larvae with plant pollen, have formations in which they collect it and transfer it to their nests; at the same time they pollinate the flowers.

Not a single animal can do without plant food and either feeds on it directly or consumes it indirectly. In turn, plants have evolved highly complex relationships with mobile land animals.

The relationship that develops between plants and herbivores can also be seen as a predator-prey relationship. But plants, unlike animal victims, cannot hide or run away. Seemingly so defenseless, they are simply doomed to be completely eaten by voracious herbivores. However, this does not happen - at least on land, where plant biomass is thousands of times greater than animal biomass. Even huge herds of African antelopes and zebras or, on the contrary, reindeer in the polar tundra are not able to destroy the lush greenery. The question involuntarily arises: why? In response, two hypotheses can be put forward, which are not mutually exclusive. According to the first, herbivores cannot eat a significant part of the vegetation, since there are never too many of them. And predators do not allow them to increase their numbers. Simply put, plants are so abundant on land because lions do not allow antelopes to multiply excessively, lynxes - hares, owls - voles, and starlings and tits - insects. According to the second hypothesis, herbivorous animals leave many plants intact only because they are not a complete food for them or are protected from eating by thorns, burning hairs, hard bark, or potent poisonous substances. Of course, animals try to somehow bypass these means of protection (not to die of hunger), and in the process of evolution they become more and more sophisticated in this matter. But the plants do not lag behind, "honing" the means of defense. Among these "inventions" are two substances that are most common in the plant world. These are cellulose (fiber) and lignin. Cellulose is a complex polymer consisting of sugar residues, and lignin is also a polymer, but consisting of phenolic rings. Combining with cellulose, lignin makes plant tissues lignified. Both substances are very resistant, durable, but both are “cheap” materials for the plant, since they almost do not require any scarce chemical elements for their construction. By providing mechanical support to plants, these substances are a "tough nut" for those who want to feast on them. The substances necessary for their breakdown are absent in animals, and those of them who consume large amounts of cellulose are forced to turn to the help of microorganisms. The most famous examples of the community of animals and microorganisms are various ruminants. Their complex stomachs are inhabited by a huge number of bacteria, as well as small flagellates and rather large ciliates that are not found anywhere else, carrying out the decomposition of cellulose. In 1 cm3 of the contents of the stomach of a sheep, there are up to 16 million bacteria, 1 million flagellar protozoa and 330 thousand ciliates! At the same time, the volume of the liquid contents of the stomach in a sheep is approximately 6 liters, and in a cow - about 80 liters. .Recycling lignin is even more difficult than cellulose. Most successfully, not bacteria, but fungi cope with this. An amazing example of the use of fungi for the processing of cellulose and lignin is demonstrated by tropical leaf-cutting ants. They cut pieces of fresh leaves and drag them to a special underground chamber, where special types of fungi grow on the rotting remains of these leaves, which are consumed by ants. Even better, plants can protect themselves from animals by accumulating tannins in their tissues - complex phenolic compounds that interact with proteins and stop the digestion of food. Many plants synthesize toxic substances. There are a lot of them: tens of thousands. Some of the most famous are alkaloids (these include nicotine, caffeine, strychnine and other potent substances). Some plants synthesize cyanide compounds that block the respiration of animals. However, no matter how poisonous some plants are, there is almost always one or two species of animals,

developed the ability to tolerate or neutralize the effects of poisons. And there are those who "learned" to accumulate poisons created by plants in their tissues and defend themselves from predators. The most famous example is the monarch butterfly found in North America. Its caterpillars feed on milkwort plants containing cardenolides in their tissues - substances that disrupt the cardiac activity of birds and mammals. If some inexperienced bird grabs a caterpillar or an adult butterfly, then it will immediately spit it out and will never touch it again.

To say that despite the fact that plants develop peculiar protective mechanisms over time, they are the main food for herbivores, insects and birds, because this is a vicious circle (a food chain that closes by the fact that the excrement of the latter becomes fertilizer for plants) no and meaning, because everyone knows it. But, nevertheless, in a certain sense, relationships with animals are beneficial for plants, since with the help of them some plant species reproduce. Plants use wind, water, and animals to disperse seeds. When seeds and fruits are distributed by animals (zoochoria), two types are distinguished: the seeds can, in a germinating state (having previously entered the stomach of the animal with food), return to the ground along with feces - endo-zoochory; or, with another method of distribution - they can disperse, usually clinging to the wool or other external integuments of animals - epizoochory. Very interesting is the distribution of seeds by ants - myrmecochory. In the flora of central Europe, there are surprisingly many plants whose seeds are carried by ants. Seeds can thus be a few meters, and very far from the mother plant, but the goal is still achieved! The seed was in a new place where it might germinate.

In the herbaceous and shrubby layers, many plants carry various trailing devices (clinging fruits) on ripe fruits, which, with their hooks, cling to the hair of mammals making their way through the thickets. In such cases, the seeds are usually easily separated from the plant and dispersed over different distances (epizoochore seed dispersal). Of these plants, the seed of burdock is primarily remembered. This type of fruit can hang for a long time, hooked on our dress. In the same way, they get stuck in the fur of mammals and are carried by them often over long distances, until they finally fall to the ground. And there are many such examples.

The purpose of the lesson: to introduce students to the manifestation of the relationship between plants and animals.

• To develop students' knowledge of the relationship between animals and plants.
• To deepen knowledge about animals - pollinators, herbivores, granivorous animals, plants - predators (sundew, common oilwort, venus flytrap).

Developing:

• Continue to form the ability to find relationships between the relationships of animals and plants; develop students' speech.

Educational:

• Continue the aesthetic education of students in the classroom.

Equipment:

Tables on biology “mixed forest ecosystem”, ecological lotto, plates for a skit.

During the classes

Teacher: In the last lesson, we studied the relationship between animals: these are mutually beneficial relationships, lodging, freeloading, predation, competition. And now let's check how you learned the material.

I. Group work.

Teacher: Let's play "Ecological Lotto". The envelopes contain pictures of animals, cards with the names of relationships. It is necessary to lay down, correctly, the relationship between animals.

II. Individual survey.

– Tell us about mutually beneficial relationships between animals?

- What does swindle mean?

- Describe predation?

What do you know about animal competition?

III. Setting the objectives of the lesson.

Teacher: In the last lesson we studied the relationship of animals. But in nature, the life of any animal is directly or indirectly connected with plants. And they interact with each other, these relationships can be beneficial or harmful. That's what we'll talk about today.

Write in your notebook the date and the topic of our lesson. (The work of students in a notebook).

IV. Work on the study of new material. (The material is presented in the form of an excursion)

Teacher: Plants play a big role in the life of animals, just like animals in the life of plants. But first things first.

(On the board is a diagram - “The importance of plants in animal life” The teacher's story is accompanied by presentation slides, in accordance with the diagram.)

"The Importance of Animals in Plant Life".

1. Plant pollinators; (see slide number 4)
2. Plants inhale the carbon dioxide exhaled by animals; (see slide number 5)
3. Distribution of fruits and seeds; (see slide number 6)
4. Destroy seeds, affect renewal; (see slide number 7)
5. Animals break and trample plants; (see slide number 8)

Teacher: Now let's take a closer look at these relationships. And we will build an acquaintance in the form of a correspondence excursion into nature. Thanks to the imagination, we can easily get into the forest, the clearing, the swamp. And we can afford to hear the conversations of plants. Let's start. Look closely, we are in the meadow. (see slide number 9). There is a rumble in the air from bumblebees, wasps, and bees flying over the flowers. In the air, motley flickering of butterflies, beetles. This is the work of insects - pollinators. In this they succeeded. An insect feeds on the nectar of plants, and spreads pollen from one plant to another. As a result, many seeds are formed - which will give life to other plants.

The connection between bumblebees and clover has long been noticed. Only bumblebees, with their long proboscis, can get nectar from clover flowers while transferring it from flower to flower. The importance of bumblebees in pollinating clover was noticed in Australia, when Europeans brought seeds to this continent and sowed them. The seedlings that appeared began to grow rapidly, the plants soon bloomed, but the seed crop was not given. It turned out that there were no insects in Australia that could feed on the nectar of a clover flower and pollinate them. Then bumblebees were brought to the continent, and clover began to produce seeds.

But there are plants that bloom at night, and there are nocturnal insects - pollinators.

Teacher: And now let's listen to the voices around us, maybe we'll hear something.

(Scene No. 1. Characters: Nature, Clover, Ecologist.)

Nature: We get a lot of questions, are plants happy with how insects pollinate them? Isn't the fee they charge for their work too high? Maybe something needs to be changed in the relationship? Who will answer us? Clover?

Clover: We insect pollinators are very pleased with the way we are pollinated by insects - pollinators. In tropical countries, they are helped in this matter by birds - hummingbirds and even mice. But in our temperate climate, only insects pollinate us. And we do everything so that insects - pollinators can do it.

Nature: And what are you doing for this?

Clover: We dress up in beautiful corollas and collect our flowers in inflorescences so that it is easier for pollinators to see us from afar, it is more convenient to pollinate, moving from one flower to another. In addition, we exude fragrances that are pleasant to insects and attract them. And finally, we share with them some of the pollen, we have quite enough of it.

Nature: Do you care what insects come, or do you have your own favorites?

Clover: We don't like being served by many different insects. Indeed, in this case, they can transfer our pollen to the wrong plants at all. In this case, we will waste both nectar and pollen in vain.

Nature: What are you doing to ensure that each species has its own pollinators?

Clover: We come up with special flower shapes that limit our pollinators.

Ecologist: I will note that among insect-pollinated plants there are also big fussinesses. Which are friends with only one species of pollinators. The flowers of some orchids smell like female pollinating insects. And the males, at their call, pollinate the plants.

(Scene No. 2 Characters: Nature, Bluegrass, Ecologist.)

Nature: I would love to see plants talk about how they feel about those who eat them.

Bluegrass: I and my relatives, cereals, the basis of meadows and steppes. We are the main fodder plants for large herbivores and insects. And we are not mad at them, who eat us. We have a good relationship with us. If we were not eaten, then the reserves of substances would not return to the soil, and we get these elements from it. And we would starve.

Ecologist: It's bad when inedible grass accumulates in the steppe. It covers the soil very poorly, accumulates water and gives growth to other plants. And the steppe grasses are dying. So the plants benefit from being eaten.

Nature: That's good, but how do plants manage to escape from those who have an excessively large appetite?

Ecologist: It's simple, only those plants that grow easily and quickly after being eaten are tasty.

Nature: But large animals sometimes eat plants under the root. Is there a way for plants to protect themselves from them?

Bluegrass: There is. If there are too many grazers, then plants of a squat form grow, which are inaccessible to their teeth. This is plantain, dandelion.

Teacher: Yes, plants are not averse to giving food to animals if there are not many of them, because. the digested parts of the food return as manure to the soil and fertilize it, giving nutrition to the plants.

But many ungulates, eating plants, break, trample them, trying to get young shoots from the tops of plants. By doing this, they change the shape of plants. But not only large animals feed on grass, but also small ones. Look, here a grasshopper fits on a blade of grass, as green as the grass itself and works hard with its jaws.

(Scene No. 3 Characters: Nature, Clover, Ecologist.)

Nature: Have you forgotten about small herbivorous insects?

Clover: Most of us have a lot of leaves. And the top sheets obscure the bottom ones. And these leaves spend a lot of substances during respiration, but they create little. We also have a lot of flowers and a lot of ovaries, and not all of us can grow. Therefore, if insects eat part of the ovary, this is useful for us.

Ecologist: For trees in the garden, so that they give a harvest, the gardener cuts off extra branches. Grasses also need pruning. The role of gardeners is performed by insects - leaf beetles.

Nature: And if this happens to cultivated plants, such as wheat, what will happen?

Ecologists: If insects eat some greenery, then this is not scary for them, but even useful.

Teacher: But many insects, such as locusts, are a relative of our grasshopper. (see slide number 11), can eat all the grass on the vine, leaving only bare ground. This is bad - there are no seeds, no renewal of these herbs.

– But not everything is so bad, hear the knock. It's a woodpecker (see slide number 12). He hurries to help the affected plants, and he himself receives both a table and a house from the plants. Woodpeckers use for food, the seeds of spruce and pine, the larvae of beetles - barbels and beetles - bark beetles, this is their food. In addition, hollows are made in tree trunks and chicks are hatched. Feeding on various beetles and their larvae, woodpeckers save trees and they feel good and actively bear fruit, giving food to woodpeckers.

- Yes, and other birds also help the trees - saving them from pests, such as nuthatches, tits. So the birds must be treated with care.

Teacher: And now back to the steppe plants, there are a lot of cereals that give grain and a lot of rodents (hares, hamsters, voles, ground squirrels) (see slide number 13). They use stems, leaves, and seeds for food. Many birds feed on grain. And if there are a lot of granivorous and rodents, you can see the replacement of some plants by others.

Teacher: And now we are waiting for the most amazing thing in our excursion. Plants are predators, and you need to look for them in a swamp and in a pond. Predators are not only among animals. In swamps, an insectivorous plant is often found - sundew (see slide number 14). The rounded leaves of sundew are covered with reddish cilia that secrete sticky juice. Small insects landing on sundew stick to its leaves. The cilia bend and hold the prey. Sundew leaves secrete a juice that digests captured insects.

- An equally interesting plant grows in ponds and lakes - pemphigus (see slide number 15). Its leaves are cut into thin slices, on which small air-filled bubbles form. The bubble has a hole with a valve that can be folded inward. Small animals, even fish larvae, once in the bubble, cannot get out of it because the hole is closed by a valve. Pemphigus uses dead animals as additional food.

Teacher: And now we get to the apiary (see slide number 16). Let's see how man uses the relationship of plants and insects.

- During the flowering of the sunflower, beehives with bees are taken to the fields. Collecting nectar and pollen, bees pollinate sunflower flowers. In such fields, sunflower yields high yields, and a lot of honey is produced in the hives.

Teacher: Let's go back to class. And now we need to draw up a report on the excursion. From statements 1 to 6, choose the correct one and write it in your notebook.

Statements:

1. Feeding on various beetles and their larvae, woodpeckers save trees from drying out.
2. Plants with a strong smell bloom at night, but no one pollinates them.
3. Only bumblebees, with their long proboscis, can get nectar from clover flowers and at the same time transfer its pollen from flower to flower.
4. In the forest, birds do not collect insect pests from trees, the trees destroy them themselves.
5. Nocturnal insects pollinate flowers that bloom at night.
6. Predators are not only among animals. In the swamp there is a predatory plant - sundew.

Checking the correctness of the answers.

Lesson analysis.

Diary work.

Homework: (find examples of relationships between organisms).