Interactions between plants and animals
The purpose of the lesson: p to acquaint students with the manifestation of the relationship between plants and animals, man .
Tasks:
Training:
· To develop students' knowledge of the relationship between animals and plants.
· Deepen knowledge about animals - pollinators, herbivores, granivorous and predatory 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: Pictures with images of animals;textbook: Pleshakova A.A. "The world around"; record player.
During the classesI. Organizing time.
The bell rang loudly
The lesson starts.
Our ears are on top,
Eyes opened wide
We listen. remember,
We don't waste a minute.
What is related to nature?
What about inanimate nature?
A record is opened on the board after the children's answers.
(sun, air, water, minerals, soil).
II. Live nature. Front work.
1.
What is related to wildlife?
The entry on the board opens after the children's answers
(plants, animals, fungi, bacteria, viruses).
2.
Today in the lesson we will talk about plants, animals and humans.
Opening diagram on the board
3. What role does the sun play? (heat, light, energy)
4. What role do plants play in nature?
5. What role do animals play in nature?
6. Is there a connection in nature between plants, animals and humans?
Children: Plants give oxygen, home, food to humans. And animals pollinate plants, carry seeds, fertilize, loosen the soil.
Conclusion…
Connection…
||| . Work on the study of new material.
Today we will discuss the topic in the lesson: The role of plants, animals in nature and people's lives.
Teacher: Plants play an important role in the life of animals, just as animals play 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.)
Plants are the basis of life on earth. They enrich the air with oxygen, which is necessary for the respiration of all living beings. They create complex substances from simple ones.(food) . It is only thanks to plants that animals and humans appeared and exist on Earth.
What do plants give to animals and animals to plants? (The relationship of plants and animals)
2nd group . What do plants give to a person (The role of plants in human life)
3rd group . What do animals give to humans? (The role of animals in human life)
4th group . Show on a diagram what happens if:
Will a man cut down all the trees in the forest?
Will people wash cars in a pond?
We agreed that we would figuratively call the plants breadwinners.
Can animals create their own food in the same way that plants can?
No. Animals eat cooked food. Herbivorous animals eat plants. Predators prey on other animals. Sick and weak animals get into their teeth more often than strong and healthy ones. If there are no predators, then there will be too many herbivorous animals. They will eat all the plants and starve to death.
W: - And how did we decide to figuratively name all the animals?
D:- We call all animals eaters. (Predators)
W: - Let's clarify the differences between animals and plants.
D:- Animals are different from plants:
· according to the method of nutrition;
· by the way of breathing (plants are able to purify the air);
· by color (green color prevails in plants).
U: (M H) - Our observations show that every living organism has adapted to coexist with other living organisms. (Shows slide number 5). Plants create complex substances from simple ones and serve as food for herbivorous animals. And those, in turn, are food for predators.
Wu: - Sooner or later, all plants and animals grow old and die. Their remains fall into the soil. Small soil animals and the smallest organisms - we agreed to call them "scavengers" - turn complex substances back into simple ones. Thus, they again become suitable for plants. Consequently, a circular connection of the living and non-living was obtained.
W: - What problematic question does the Ant Question on page 9 offer us to solve?
Let's think about what happens if at least one link from our chain disappears (plants - herbivores - predators - soil organisms)?
: - If all plants disappeared, there would be no food for herbivores and oxygen for breathing. Herbivores would disappear - there would be too many plants, they could not grow; Predators would also disappear, since they would have nothing to eat. Predators would disappear - there would be too many herbivores, they would eat all the plants. Scavengers would disappear - no one would destroy the bodies of the dead, they would fill the whole earth.
W: What can we conclude from our observations?
D: - There is nothing superfluous in nature. Everything in nature is interconnected.
W: - Compare your assumptions with the conclusion in the textbook on page 9. What will be the additions?
D: - A person should not disturb the natural balance.
And can anyone of you explain the meaning of the word "ecology".
Ecology is the science of how animals and plants, in general, all living organisms get along with each other, how they have adapted to each other and the environment. We will talk about this. Just remember first:
· what objects are not related to nature,
· who we call living organisms,
· what are the properties of living organisms;
· which refers to inanimate nature.
D: - Items made by human hands do not belong to nature. Everything that surrounds us that has existed, exists and will exist regardless of man and his efforts, belongs to nature. (Shows slide number 3). Nature is both living and non-living. The main features of the bodies of living nature are nutrition, respiration, reproduction, growth and death. Only if all these signs are present, the body can be attributed to living nature. Therefore, the objects of inanimate nature are: stars, stones, air, water:
W:-
Consider both groups (plants and animals) in more detail. How do plants build their bodies?
D:- Plants build their body from air, soil moisture and nutrients dissolved in the soil.
W:- Plants use the power of sunlight to do this. Open your textbook on page 8. What is shown in the first picture?
D:- In the first drawing, the artist painted plants: meadow grasses, shrubs and trees.
W:- Read the text under the illustration and say what important plant ability we have not talked about yet.
D:-
IV. Fizkultminutka. Element of breathing exercises.
Guys, how many of you know what ecology is?The science of the relationship between plants, animals and the environment.
How do you understand the word relationship?
What relationships do you know in nature?
1. "animal - plant"
2. "animal animal"
3. "animal - human"
– Today we will talk about these relationships.
- What do you think is necessary for the growth and development of animals? (Food)
- Do you know what groups animals are divided into according to the type of food?
- Let's remember what animals eat. (Children's answers)
- From your answers it is clear that nutrition in the animal kingdom is diverse. Let's try to divide all animals into groups depending on their appearance and their food. (Children answer)
Conclusion #1:
1. If animals eat plant foods, then they are called herbivores;
2. If they eat other animals, they are predators;
3. If they feed only on insects, they are insectivorous;
If they eat both plants and animals, then they have the title of omnivores.
(Slide number 9, 10, 11,12,13)
- Sort the animals by type of food, continuing the table in a notebook.
(Group work in progress)
- What conclusion can we draw from the first point of the plan?
Conclusion #2:
1. Animals according to the type of food are divided into herbivores, insectivores, predators, omnivores.
(Slide number 14)
Conclusion #3:
1. Plants are the first link in the food chain, as they themselves form nutrients with the help of water, light and carbon dioxide.
2. Plants are eaten by herbivores and omnivores.
3. Herbivorous - eat insectivores, predators and omnivores.
4. Insectivores are carnivores and omnivores.
5. Predators are omnivores.
4. Physical education minute
5. Consolidation of new material.
Game "Know the animal"
6. Summing up.(Slide #21)
- What conclusions can be drawn from our lesson? (Students give their opinion)
- What new things have you discovered for yourself?
- What would you like to know more about?
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".
- Plant pollinators; (see slide number 4)
- Plants inhale the carbon dioxide exhaled by animals; (see slide number 5)
- Distribution of fruits and seeds; (see slide number 6)
- Destroy seeds, affect renewal; (see slide number 7)
- 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 dissected 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:
- Feeding on various beetles and their larvae, woodpeckers save trees from drying out.
- Plants with a strong smell bloom at night, but no one pollinates them.
- Only bumblebees, with their long proboscis, can get nectar from clover flowers and at the same time transfer its pollen from flower to flower.
- In the forest, birds do not collect insect pests from trees, the trees destroy them themselves.
- Nocturnal insects pollinate flowers that bloom at night.
- 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).
Topic: Relationships in nature. The concept of the ecological pyramid
Purpose: Formation in children of the idea of the relationship between the inhabitants of the forest - plants and animals, their food addiction.
Tasks:
1 Educational: generalize children's ideas about animals, their appearance, habitat, dependence on humans.
2 Expand ideas about the characteristics of animal nutrition in nature.
Developing:
3 To consolidate knowledge about the characteristics of wild and domestic animals.
4 Raise interest in the nature of the native land.
Educational:
5 Cultivate a benevolent attitude towards nature in general.
Course progress.
Educator: Due to the fact that 2017 is declared the Year of Ecology, the Community of Young Ecologists of our city sent us this wonderful book by April 15 (Ecological Knowledge Day) and invites us to join the ranks of young ecologists.
slide
(Q: What month is it now? Season?...) There is time until April, but in order to join the ranks of the Young Ecologists, you need to show your knowledge.
Q: open our book
Who is it? (animals), which ones? (wild), how can they be divided according to the way they eat? (predators and herbivores, list them).
Pay attention to the bear: is it really a predator ?, because he has a sweet tooth and loves to eat berries, honey, roots? (A predatory bear, because it eats small animals that it can get and can attack a person).
The wolf is definitely a predator!
Slide
What does the wolf like to eat? (hare)
What do you think, should there be more hares in nature than wolves or equally, so that everyone has enough? (There should be more hares in nature, because some of the hares should give offspring)
If we take a rectangle, which one will be larger, the one that denotes wolves or hares? (hares)
Slide
Q: But hares do not exist on their own, they also need to eat, what? (grass)
How much grass should be in nature? (a lot, because the grass is animal food, a house for insects, humus for the forest)
If hares and grass are denoted by a rectangle, which one is larger? (the one that stands for grass)
Slide
Q: what kind of structure did it turn out, what does it look like? (children's guesses)
Is it possible to make it even more? What can be added? (earth, water, sun ...).
What geometric figure does it resemble? (triangle, pyramid) - in biology this is called an ecological pyramid.
Slide
Game: build an ecological pyramid!
The teacher divides the children into teams of three. Each team receives 3 cards with printed words, for example: lynx, grass, antelope. The teacher invites the children of one team to read, confer and line up in an ecological pyramid, starting with a predator.
2nd team: leaf, caterpillar, bird
3rd team: grass, ladybug, aphids
4th team: acorns, mice, fox
etc
Q: Everything in nature is interconnected, all inhabitants, plants and animals, depend on each other.
Is it possible to remove a member of the ecological pyramid from nature?
Slide
Q: imagine that the hares have disappeared! (Children's answers) -
the wolf and other predators have nothing to eat and they will begin to die out.
Slide
Q: imagine that there will be no wolf! (Children's answers)
At first, the hares will be fine, there will be a lot of them, but then there will be little grass, they will start to get sick and die out.
Q: Who can help nature keep its balance? (man)
What does a person do to preserve the number of animals? (reserves, wildlife sanctuaries, the Red Book, zoologists monitor the number of animals in nature, ecologists help in the construction of treatment facilities ....)
How can we help in protecting nature? (do not burn fires, do not throw garbage in the forest, do not kill insects, feed birds, do not fish with electric fishing rods ...)
Productive activity: choose your own animals and build an ecological pyramid (application).
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.
Lecture 9 and 10. Relationships in the cenosis, types of relationships between organisms. Conjugation of species.
TOPIC: FUNCTIONAL STRUCTURE OF BIOGEOCOENOSIS (2 lectures)
Lecture 9. INTERRELATIONS IN BIOGEOCOENOSIS. TYPES OF RELATIONSHIPS BETWEEN ORGANISMS IN CENOSIS
FOREWORD
The first two lectures on the structure of biogeocenosis dealt with the species composition and spatial structure of phytocenosis as the main component of biogeocenosis. This lecture discusses the functional structure of the biocenosis. V.V. Mazing (1973) distinguishes three directions developed by him for phytocenoses.
1. Structure as a synonym for composition(species, constitutional). In this sense, they speak of species, population, biomorphological (composition of life forms) and other structures of the cenosis, meaning only one side of the cenosis - the composition in the broad sense.
2. Structure as a synonym for structure(spatial, or morphostructure). In any phytocenosis, plants are characterized by a certain confinement to ecological niches and occupy a certain space. This also applies to other components of biogeocenosis.
3. Structure as a synonym for sets of connections between elements(functional). The understanding of the structure in this sense is based on the study of relationships between species, primarily the study of direct relationships - the biotic connex. This is the study of food chains and cycles that ensure the circulation of substances and reveal the mechanism of trophic (between animals and plants) or topical (between plants) connections.
All three aspects of the structure of biological systems are closely interconnected at the coenotic level: the species composition, configuration and placement of structural elements in space are a condition for their functioning, i.e. vital activity and production of plant mass, and the latter, in turn, largely determines the morphology of cenoses. And all these aspects reflect the environmental conditions in which biogeocenosis is formed.
Bibliography
Voronov A.G. Geobotany. Proc. Allowance for high fur boots and ped. in-comrade. Ed. 2nd. M.: Higher. school, 1973. 384 p.
Mazing V.V. What is the structure of biogeocenosis // Problems of biogeocenology. M.: Nauka, 1973. S. 148-156.
Fundamentals of forest biogeocenology / ed. Sukacheva V.N. and Dylissa N.V.. M.: Nauka, 1964. 574 p.
Questions
1. Relationships in biogeocenosis:
3. Types of relationships between organisms in the cenosis:
a) Symbiosis
b) Antagonism
1. Relationships in biogeocenosis
Biocenotic connex- a complex tangle of relationships, the "unwinding" of which can be done in various ways. Under the ways of deciphering the functional structure, separate approaches are meant.
Biogeocenosis as a whole is the laboratory in which the process of accumulation and transformation of energy takes place. This process is composed of many different physiological and chemical processes that also interact with each other. Interactions between the components of biogeocenosis are expressed in the exchange of matter and energy between them.
The relationship between organisms and the environment, which constitute one of the foundations for understanding the essence of biogeocenosis, refers to ecological direction. Relationships between individuals of the same species are usually related to population level, and the relationships between different species and different biomorphs form the basis of already biocenotic approach.
a) Interaction between soil and vegetation
The interaction between soil and vegetation all the time takes place in a certain sense of the "circulation" of matter and the pumping of mineral substances from various soil horizons to the above-ground parts of plants, and then returning them to the soil in the form of plant litter. Thus, the redistribution of mineral substances of the soil over its horizons is carried out.
A particularly important role in this process is played by litter, the so-called forest litter, that is, a layer accumulating on the surface of the soil itself from the remains of leaves, branches, bark, fruits and other parts of plants. The destruction and mineralization of these plant residues occurs in the forest litter.
Vegetation also plays an important role in soil water regime, absorbing moisture from certain soil horizons, then releasing it into the atmosphere by transpiration, affecting the evaporation of water from the soil surface, affecting the surface runoff of water and its underground movement. At the same time, the influence of vegetation on soil conditions depends on the composition of vegetation, its age, height, thickness and density.
b) Interactions between vegetation and the atmosphere
No less complex interactions are observed between vegetation and the atmosphere. The growth and development of vegetation depend on temperature, air humidity, its movement and composition, but vice versa - the composition, height, layering and density of vegetation affect these properties of the atmosphere.
Therefore, each biogeocenosis has its own climate ( phytoclimate), i.e. those properties of the atmosphere that are caused by the vegetation itself.
c) The relationship between microorganisms and different components of biogeocenosis
At the same time, microorganisms directly or indirectly interact with animals (both vertebrates and invertebrates).
d) Relationships between plants
Other "influences" of plants: weakening the action of the wind, protection from windfall and windfall; accumulation from dying and falling plant residues, leaves, branches, fruits, seeds, etc. forest litter, which not only indirectly affects plants through changes in soil processes, but also creates special conditions for seed germination and seedling development, etc.
The study of biomorphs as models of the most significant ecological features of species is promising in elucidating general cenogeographic patterns.
e) The relationship of vegetation with the animal world
No less close is the relationship of vegetation with the animal world inhabiting this biogeocenosis. Animals in the course of their life activity affect vegetation in many ways, both directly, feeding on it, trampling it, building their dwellings and shelters in it or with the help of it, facilitating the pollination of flowers and distributing seeds or fruits, and indirectly, changing the soil, fertilizing it, loosening , generally changing its chemical and physical properties, and to some extent affecting the atmosphere.
The relationship between different trophic levels belongs to the trophic-energy direction (Odum, 1963) and is the object of many studies that have been widely developed in recent decades. This makes it possible to reveal the general nature and quantitative indicators of metabolism and energy, thereby revealing the biogeophysical and biogeochemical role of the living cover.
f) Interactions between non-living (abiotic) components
Not only living organisms interact with other components of the biogeocenosis, but these latter also interact with each other. Climatic conditions (atmosphere) affect the soil-forming process, and soil processes, determining the release of carbon dioxide and other gases (soil respiration), change the atmosphere. The soil influences the animal world, not only inhabiting it, but indirectly the rest of the animal world. The animal world affects the soil.
2. Factors affecting the interaction of biogeocenosis components
Relief and biogeocenosis. Any biogeocenosis, occupying a certain place in nature, is associated with one or another relief. But the relief itself is not among the components of the biogeocenosis. The relief is only a condition that affects the process of interaction of the above components, and, in accordance with this, their properties and structure, determining the direction and intensity of the interaction processes. At the same time, the interaction of the components of the biogeocenosis can often lead to a change in the relief and the creation of special forms of microrelief, and in certain cases both meso- and macrorelief.
Human influence on biogeocenosis. Man is not among the components of biogeocenoses. However, it is an extremely powerful factor that can not only change to some extent, but also create new biogeocenoses through culture. Nowadays, there are almost no forest biogeocenoses that have not been influenced by economic, and often mismanaged human activities.
Mutual influences between biogeocenoses. At the same time, each biogeocenosis, one way or another, affects other biogeocenoses and, in general, natural phenomena that are adjacent to it or, to some extent, remote from it, i.e., the exchange of matter and energy takes place not only between the components of this biogeocenosis, but and between the phytocenoses themselves. Often the leading factor is the competitive relationship between phytocenoses. A more powerful phytocenosis displaces a less stable phytocenosis, for example, under certain conditions, a pine phytocenosis is replaced by a spruce one, and at the same time the entire biogeocenosis changes.
Thus, the interaction of all components of biogeocenosis, especially forest biogeocenosis (including water in soil and atmosphere), is very diverse and complex:
Vegetation is always dependent on soil, atmosphere, wildlife and microorganisms.
The chemical composition of the soil, its moisture and physical properties affect the growth and development of plants, their fruiting and renewability, the technical properties of their wood and tree species, their growth and development of all other vegetation.
All vegetation, in turn, has a strong effect on the soil, determining mainly the quality and quantity of organic matter in the soil, affecting its physical and chemical features.
3. Types of relationships between organisms in the cenosis
Organisms can interact with each other constantly, throughout their lives, or for a short time. At the same time, they either come into contact with each other, or affect another organism at a distance.
Mutual influences of plants can have something favorable for their growth and development of character, then adverse. In the first case, they conditionally speak of "mutual assistance", in the second - about the "struggle for existence" between plants in the broad, Darwinian sense, or about competition. It goes without saying that all these mutual influences between organisms in a biocenosis at the same time play an important role in the biogeocenosis as a whole. They can pass between individuals both of different species and of the same species, i.e., they can be both interspecific and intraspecific.
The relationships between organisms are very diverse. The classification of these relations by G. Clark (Clark, 1957) is successful (Table 1).
Table 1
Classification of relationships between organisms (according to Clark, 1957)
| View A | View B | Relations Conventional signs: "+" - an increase or benefit in the life process as a result of relationships, "-" - a decrease or damage, 0 - the absence of a noticeable effect. - relations between organisms, usually of different species and in more or less prolonged contact, in which one or both organisms benefit from these relations and neither suffers damage. The first type of symbiotic relationship, when both organisms benefit, is called mutualism, the second, when only one of the organisms benefits, is called commensalism (“freeloading”). Mutualism Symbiosis of nitrogen-fixing organisms with gymnosperms and flowering plants - the relationship between a higher plant and bacteria. On the roots of many plants there are nodules formed by bacteria or, less commonly, fungi. Nodule bacteria fix atmospheric nitrogen and convert it into a form accessible to higher plants.
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In each phytocenosis, plants are selected:
Representing various life forms and occupying a place in various synusia, tiers, microcenoses, i.e. forming groups characterized by an unequal attitude to the environment and an unequal place in the phytocenosis;
Differentiated by the timing of the passage of seasonal phases.
The combination in one phytocenosis of plants with different ecological features - shade-loving and light-loving, to varying degrees adapted to a lack of moisture and other environmental factors, allows the phytocenosis to make the most full use of habitat conditions.
The change of species does not occur immediately, gradually one species displaces the other, so there is usually no clear boundary between phytocenoses. The strip on which the change of phytocenoses occurs is called the ecotone. In the ecotone, as a rule, there are species of adjacent communities, and the mosaicity of the vegetation cover is higher here, but the life status of the dominant species of both communities in the ecotone is usually worse than in those cenoses, the conditions of which are more suitable for these species.
The displacement of some species by others at the boundary of phytocenoses (though not single-species ones) occurs even without changes in environmental conditions, as a result of different competitive abilities of species, in particular, different energies of vegetative reproduction.
EXAMPLES. Thus, the well-known wheatgrass weed is not only capable of drowning out cultivated crops, but also displaces many wild species (nettle, celandine, etc.) that grow next to it and which reproduce very weakly vegetatively. Even creeping clover is gradually giving way to couch grass.
Sphagnum moss has a very strong competitive ability. As it grows, it literally absorbs neighboring plants. In areas of permafrost distribution, phytocenoses dominated by sphagnum occupy vast areas, displacing their zones of influence not only grasses and shrubs, but also shrubs and trees.
As a result of the struggle for existence, the differentiation of species that form a phytocenosis occurs. At the same time, the structure of the phytocenosis is not only the result of the struggle for existence, but also the result of the adaptation of plants to reduce the intensity of this struggle. In the phytocenosis, the species are selected in such a way that they complement each other with their properties.
Lecture 10. ASSOCIATION OF SPECIES IN PHYTOCENOSIS. INTRA- AND INTER-SPECIES RELATIONS IN BIOGEOCOENOSIS.
Questions
a) Differentiation of cenopopulations
c) Overpopulation of the species
4. Conjugation of species in phytocenosis
One of the qualitative indicators of the species that make up the phytocenosis is their conjugation (association). Relationship is noted only by the presence or absence of two species on the trial plot. There is positive or negative conjugation.
Positive happens when species B occurs with species A more often than would be the case if the distribution of both species was independent of each other.
Negative contingency is observed when species B occurs together with species A less frequently than would occur if the distribution of both species was independent of each other.
In the textbook of geobotany A.G. Voronov provides formulas and contingency tables of V.I. Vasilevich (1969), which can be used to process data on the presence and absence of two species and determine the level of their conjugation, and an example of calculation is given.
For determining degree of conjugation two or more types, there are also different coefficients (Greig-Smith, 1967; Vasilevich, 1969).
One of them was proposed by N.Ya. Kats (Kats, 1943) and is calculated by the formula:
If K>1, then this means that this species occurs more often with another species than without it (positive contingency); if K<1, то это значит, что данный вид чаще встречается без другого вида, чем с ним (сопряженность отрицательная). Если К = 1, то виды индифферентно относятся друг к другу, и встречаемость данного вида вместе с другим не отличается от общей встречаемости первого вида в фитоценозе.
Naturally, the contingency is the higher, the more the contingency coefficient is removed from unity.
Most often, square areas of 1 m 2 are used to determine conjugation, sometimes rectangular areas of 10 m 2. B.A. Bykov proposed round platforms of 5 dm 2 (radius 13 cm). But if the size of the trial plot is commensurate with the size of an individual of at least one species, then a false impression of a negative correlation with another species will be obtained only because two individuals cannot occupy the same place. In this case, you should increase the size of the sites.
They should also be increased if, for example, there are 3 species in the phytocenosis, and individuals of one species are large, and the other two are small. On the registration area occupied by a "large" species, there may be no "small" species displaced by it. This gives the impression that there is a positive correlation between species with small individuals, which is not the case. This idea will disappear with sufficient sizes of test plots.
In cases where the goal is only to establish the presence or absence of conjugation, it is possible to lay sites "in a strictly systematic order", for example, close to each other. If the degree of conjugation is established by one of the formulas, random sampling is necessary.
What does conjugation indicate?
If it's about positive conjugation, then it can take place in two cases:
Species "adapt" to each other so much that they meet each other more often (retinues of species of certain types of forest, garlic and carrots in agriculture) than separately
Both species are similar in their ecological characteristics and more often live together because within the same phytocenosis the conditions are more favorable for both species (species of the same tiers).
At negative conjugation, it may depend on the fact that as a result of interspecific struggle:
Both species have become antagonists (no need to plant strawberries and carrots nearby; Volzhanka, reed grass - oppress their eco-niche neighbors);
Species have different attitudes to moisture, lighting, and other environmental factors within the phytocenosis (plants of different tiers and different parcels).
5. Intra- and interspecific relationships in biogeocenosis
a) Differentiation of cenopopulations
Foresters have long known that the number of tree trunks per unit area decreases with age. The more photophilous the species and the better the growing conditions, the faster the tree stand self-thinning. The death of trees is especially intense in the first decades and gradually decreases with increasing age of the forest. This is clearly shown in Table 2.
table 2
Decrease in the total number of trunks with age (according to G. F. Morozov, 1930)
| Age in years | Number of stems per 1 ha | ||
| beech forest on conchoidal limestone | beech forest on variegated sandstone soil | Pine forest on sandy soil |
|
| 10 | 1 048 660 | 860 000 | 11 750 |
| 20 | 149 800 | 168 666 | 11 750 |
| 30 | 29 760 | 47 225 | 10 770 |
| 40 | 11 980 | 14 708 | 3 525 |
| 50 | 4 460 | 8 580 | 1 566 |
| 60 | 2 630 | 4 272 | 940 |
| 70 | 1 488 | 2 471 | 728 |
| 80 | 1 018 | 1 735 | 587 |
| 90 | 803 | 1 398 | 509 |
| 100 | 672 | 1 057 | 461 |
| 110 | 575 | 901 | 423 |
| 120 | 509 | 748 | 383 |
| 130 | – | 658 | 352 |
| 140 | – | 575 | 325 |
| 145-150 | – | 505 | 293 |
 | The number of dead beech trees for 100 years (from 10 to 110 years) was more than 1 million on rich soils and more than 850,000 on poor soils, and for pine - more than 11,000, which is associated with a small number of trunks of this species already at the age of ten. Pine is very light-loving, so by the age of 10 it had a significant loss. As a result, in a hundred years, one beech tree out of 1800 on rich soils and out of 950 on poorer soils, and one pine tree out of 28 are preserved. On fig. 5 also shows that the death of more light-loving species (pine) occurs faster than shade-tolerant species (beech, spruce, fir). Thus, the differences in the rate of thinning in the forest stand are explained by: 1) different photophilous (shade tolerance); 2) an increase in the rate of growth in good conditions and, as a result, a rapid increase in its need for ecological resources, which is why competition between species becomes more and more intense. |
 | Competition within a species is much more intense than between individuals of different species, but in this case there is a differentiation of individuals in height. In the forest, trees of the same species can be divided into Kraft classes (Fig. 6). The first class combines trees that are well developed, rising above others - exclusively dominant, the second class - dominant, the third - co-dominant, with developed, somewhat squeezed from the sides, the fourth - muffled trees, the fifth - trees that are oppressed, dying or dead. A similar picture of a decrease in the number of plant specimens (this time during one season) and differentiation in height is also observed in phytocenoses formed by annual plants, for example, herbaceous saltwort (Salicornia herbacea). |
b) Ecological and phytocenotic optimums
Each type has its own optimal density. Optimum density refers to those density limits that provide the best reproduction of the species and its greatest stability.
EXAMPLES. For trees in open spaces, the optimal density is very low, they grow singly at a considerable distance from each other, but for forest-forming species it is much higher, and for swamp sphagnum mosses (Sphagnum) it is extremely high.
The value of the optimal area and the response to thickening depend on the conditions under which the evolution of the species took place: some species developed under conditions of high population density, others under conditions of low density; in some cases the density was constant, in others it was continuously changing. Species that have evolved under conditions of constant density react sharply to an increase in density beyond the limits of optimal growth by slowing down growth; species that have developed under conditions of continuously changing density react weakly to changes in density beyond the optimum.
Each type has two development optimums: ecological, affecting the size of individuals of the species, and phytocenotic, characterized by the highest role of this species in the phytocenosis, expressed in its abundance and degree of projective cover. These optima and ranges may not coincide. In nature, a phytocenotic optimum is more common, and an ecological one can be identified by artificially creating different conditions for plants.
EXAMPLES. Many halophytes develop better not on saline soils, where they form communities, but on moist soils with low salt content. Many xeromorphic rock plants have their ecological optimum in meadows.
The discrepancy between the ecological and phytocenotic optimums is the result of the struggle for existence between plants. In a number of cases, in the process of the struggle for existence, plants are pushed into extreme conditions from more favorable phytocenoses.
EXAMPLES. White fir and Ayan spruce do not grow in higher mountain zones because conditions are better there, but because Korean spruce, cedar and whole-leaved fir displace them there. Likewise, light-loving aspen and birch yield their more favorable ecotopes to dark coniferous species. In the same way, grasses from floodplain habitats are crowded out by mosses and shrubs.
c) Overpopulation of the species
To characterize the density of a species, there is such a thing as overpopulation. Consider several types of overpopulation: absolute, relative, age, conditional and local.
Under absolute overpopulation understand such conditions of thickening under which mass death inevitably occurs, which is of a general nature. (super dense sowing - the seeds are planted in a continuous layer or in two or three layers), in which, under the condition of very friendly simultaneous shoots on large plots, all plants die, except for the extreme ones).
Under relative overpopulation understand such thickening conditions under which the death of plants is more or less increased than at the optimum density for the species. In this case, the death of plants is selective. The action of selection is milder than in the case of absolute overpopulation.
Age overpopulation is understood as overpopulation that occurs with age as a result of uneven growth of root systems (for example, in root crops) or above-ground parts of plants (in trees).
Conditionally overpopulated are called highly dense phytocenoses, in which the severity of relationships between plants is reduced by a temporary delay in their growth to such an extent that thinning sometimes completely stops. Thus, many plants remain in the juvenile (youthful) state for a very long time, maintaining a very high survival rate. It is worth forcing the plants to active growth, as real overpopulation sets in. For example, strongly oppressed individuals of tree species under the canopy of a dense forest have the appearance of undergrowth.
Local overpopulation cases of overpopulation in nesting plantations of very high density and small area are called, in which, due to the small area of the nest, the survival of each individual is determined not by the position of this individual in the nest, but by its characteristics, in other words, death here is selective.
What is the significance of the phenomena of overpopulation for the struggle for existence and, consequently, for the process of evolution?
Overpopulation can take place in some cases and in some periods of plant life and is absent in other cases and in other periods of plant life. Depending on the degree of overpopulation and on the characteristics of organisms, it can both accelerate and slow down the process of evolution. With small degrees of overpopulation, it causes differentiation of individuals and thereby accelerates the process of evolution; at significant degrees, it can cause impoverishment of the population, a decrease in fertility, and as a result, a slowdown in the evolutionary process. Overpopulation slows down and accelerates the process of natural selection, but does not serve as an obstacle to it and is not an indispensable condition for selection, since selection can proceed without overpopulation.
We know that for the two largest groups of the organic world - animals and plants - the significance of overpopulation is not the same: it plays a much greater role in the plant world, since the mobility of animals allows them in some cases to escape from overpopulation.
For different systematic and ecological groups of plants, overpopulation does not play the same role. The development of a larger number of seedlings and young plants than can subsequently survive ensures the dominance of the species in the phytocenosis. If seedlings of the species predominant in the phytocenosis were single, then seedlings of another species would develop in masses, and this other species could become dominant in the phytocenosis. The dominant species usually produces a large number of seedlings, but it is quite natural that only a small part reaches maturity. This means that the death of a large number of young plants in this case is inevitable, it is this that ensures the prosperity of the species and the preservation of its position in the phytocenosis. In addition to young plants, a large number of diaspores die - the rudiments of plants (seeds, fruits, spores) - even before their development begins (they are eaten by animals, die in adverse conditions, etc.). Thus, a huge number of diaspores formed by plants ensures not only dominance, but often the very existence of the species.
Intraspecific competition is always more fierce than interspecific competition, since individuals of the same species are more similar to each other and make more similar demands on the environment than individuals of different species. However, in nature, apparently, everything is more complicated. Thus, when raising two species in pure crops and in mixed crops (moreover, the total number of individuals per unit area in a mixed crop is equal to the number of individuals per unit area in pure crops of both species), three types of relationships are observed (Sukachev, 1953).
1. When sowing together, both species develop better than either of them in a single-species sowing. In this case, the interspecific struggle turns out to be weaker than the intraspecific one, which corresponds to the point of view of Charles Darwin.
2. Of the two species, one does better in a mixture than in a pure crop, and the second is worse in a mixture and better in a pure crop. In this case, for one of the species, the interspecific struggle turns out to be more severe than the intraspecific one, and vice versa for the other. The reasons for this are different: the allocation by one of the species of colins that are harmful to individuals of another species, the difference in the ecological characteristics of the species, the influence of the decomposition products of the dead remains of one species on another, differences in the structure of the root system and other features.
3. Both species feel worse in a mixture than in single-species crops. In this case, for both species, the intraspecific struggle is less severe than the interspecific one. This case is very rare.
It should be borne in mind that the relationship between a pair of any species depends on the conditions of the experiment: the composition of the nutrient medium, the initial number of plants, lighting conditions, temperature, and other reasons.
