The formation of organic matter, both on land and in the ocean, begins with the action of sunlight on the chlorophyll of green plants. For every million photons that reach geographic envelope, no more than 100 goes to food production. Of these, 60 are consumed by land plants and 40 by ocean phytoplankton. This fraction of light provides the planet with organic matter.
Photosynthesis occurs in the heat range from 3 to 35°C. In modern climates, vegetation occupies 133.4 million km 2 of land. The rest of the area falls on glaciers, reservoirs, buildings and rocky surfaces.
At the current stage of the Earth's development, the continental and oceanic parts of the biosphere are different. There are almost no higher plants in the ocean. The area of the littoral zone where plants attached to the bottom grow is only 2% of the total area of the ocean floor. The basis of life in the ocean is microscopic phytoplankton algae and microscopic herbivorous zooplankton organisms. Both of them are extremely scattered in water, the concentration of life is hundreds of thousands of times less than on land. Previous overestimations of ocean biomass have been revised. According to new calculations, its total mass is 525 times less than on land. According to V. G. Bogorov (1969) and A. M. Ryabchikov (1972), the annual productivity of biomass on Earth is 177 billion tons of dry matter, of which 122 billion tons comes from land vegetation and 55 billion tons from sea phytoplankton. Although the volume of biomass in the sea is much less than on land, its productivity is 328 times higher (A. M. Ryabchikov) than on the mainland, this is explained by the rapid change of generations of algae.
Land biomass consists of phytomass, zoomass, which includes insects, and biomass of bacteria and fungi. The total mass of soil organisms reaches about 1-10 9 tons, and the main share (up to 99%) of the zoomass is invertebrate organisms.
In general, the biomass of land is dominated by plant matter, mainly woody ones: photomass accounts for 97-98%, and zoomass 1-3% by weight (Kovda, 1971).
Although the mass of living matter is not large in comparison with the volume of the litho-, hydro- and even the atmosphere, its role in nature is incomparably greater than its specific gravity. For example, on 1 hectare occupied by plants, the area of their leaves can reach 80 hectares, a direct business can be done, and the area of chlorophyll grains, i.e., the actively working surface, is hundreds of times larger. The area of chlorophyll grains of all green plants on Earth is approximately equal to the area of Jupiter.
Let us emphasize once again that photosynthesis is a very advanced form of energy accumulation, the amount of which is expressed as 12.6-10 21 J (3-1021 cal). This energy annually produces about 5.8-10 11 tons of organic matter on Earth, including 3.1 ∙ 10 10 tons on land. Of this number, the share of forests is 2.04-10 10, steppes, swamps and meadows are 0.38-10 10, deserts are 0.1 ∙ 10 10 and cultivated vegetation is 0.58-10 10 tons (Kovla, 1971).
1 g of cotton field soil contains 50-100 thousand microorganisms, which translates to several tons per hectare (Kovda, 1969). Some soils per 1 hectare contain up to 10 billion roundworms, up to 3 million earthworms and 20 million insects.
One of the main assumptions of the heterotrophic hypothesis is that the emergence of life was preceded by the accumulation of organic molecules. Today we call organic molecules all those molecules that contain carbon and hydrogen. We also call molecules organic because it was originally believed that compounds of this kind could only be synthesized by living organisms.
However, back in 1828 Chemists learned to synthesize urea from inorganic substances. Urea is an organic compound that is excreted in the urine of many animals. Living organisms were considered the only source of urea until it could be synthesized in the laboratory. The laboratory conditions in which organic compounds were obtained by chemists apparently, to some extent, imitate environmental conditions on earth in early period its existence. These conditions could, according to the authors of the heterotrophic hypothesis, lead to the formation organic compounds of oxygen, hydrogen, nitrogen and carbon atoms.
Laureate Nobel Prize Harold Urey, working at the University of Chicago, became interested in the evolution of chemical compounds on Earth in the early period of its existence. He discussed this problem with one of his students, Stanley Miller. In May 1953, Miller published an article entitled “The formation of amino acids under conditions similar to those that existed on Earth in the early period,” in which he indicated that A.I. Oparin was the first to express the idea that the basis of life, organic compounds, were formed during the period when the Earth’s atmosphere contained methane, ammonia, water and hydrogen, and not carbon dioxide, nitrogen, oxygen and water. Recently, this idea was confirmed in the robots of Urey and Bernal.
In order to test this hypothesis, in a specially created device, a mixture of gases CH4, NH3, H2O and H2 was passed through a system of pipes, and an electrical discharge was created at a certain point in time. The content of amino acids in the resulting mixture was determined.
An electric discharge was passed through an airtight device filled with methane, hydrogen and ammonia, designed by Miller. Water vapor came from a special device connected to the main part of the device. The steam, passing through the device, cooled and condensed in the form of rain. Thus, the laboratory quite accurately reproduced the conditions that existed in the atmosphere of the primitive Earth. These include heat, rain and brief flashes of light. A week later, Miller analyzed the gas that was under experimental conditions. He discovered that the previously colorless liquid had turned red.
Chemical analysis showed that some compounds appeared in the liquid that were not present at the beginning of the experiment. The atoms of some gas molecules recombined to form new and more complex organic molecules. By analyzing the compounds in the liquid, Miller discovered that they form organic molecules, known as amino acids. Amino acids are made up of carbon, hydrogen, oxygen and nitrogen atoms.
Each carbon atom is capable of forming four chemical bonds with other atoms. Miller's experiments indicate that similar processes could have occurred in the Earth's atmosphere in the early period of its existence. These experiments provided important confirmation of the heterotrophic hypothesis.
7th grade.
Lesson______
Subject: Formation of organic substances in a plant.
The purpose of the lesson : to form students’ understanding of the formation of organic substances in a plant.
Tasks:
Oeducational : will repeat students’ knowledge about the external structure of a leaf, the variety of leaves. Explain the concepts of “chlorophyll”, “photosynthesis”, “plant nutrition”, introduce students to the process of formation of organic substances and the conditions for their formation,with the meaning of leaves for plants,the importance of green plants for life on Earth.
correctively - developing: development of coherent speech, enrichment of the vocabulary with new concepts, development of mental operations (ability to compare, generalize, draw conclusions,establish cause-and-effect relationships); - educational: cultivate a caring attitude towards nature,promote in children a sense of responsibility for the state of the environment.
Lesson type – combined.
Form of organization: cool lesson.
Equipment : computer, presentation on the topic “Formation of organic substances”, laboratory equipment for demonstrating experiments, tasks for individual testing, cards with educational materials and tasks, test handouts, herbarium, textbook Biology 7th grade.
1. Organizational moment.
Checking students' readiness for the lesson. Psychological mood.
Mobilizing start.
Emerging from the buds
They bloom in the spring,
In summer they rustle
In autumn they fly.
2. Checking homework. « External structure leaf. Variety of leaves.
A). Frontal survey:
What is a leaf?
From which organ of the embryo does it develop?
What is the external structure of the leaf?
How can a sheet be attached?
What types of venation do you know?
Which plants have arcuate and parallel veins?
What plants do reticulate venation belong to?
What is the importance of veins in plant life?
Which leaves are called simple and which are compound?
b). Working with cards.
Card “External structure of leaves, variety of leaves”
1. Complete the sentences:
A leaf is _____________________________________________________
2. What does the leaf consist of? _________________________________________
3. Determine leaf venation
4. Which leaves are called simple?
5. Which leaves are called compound?
__________________________________________________________________________________________________________________________
6. Connect with arrows:
Simple leaves Compound leaves
V). Working with the herbarium. Independent work
Now you have to complete the task. Look at plant leaves and study appearance leaf and shape, determine the type of venation. Present the studied data in a table.
Plant name
Leaf shape
Simple or complex
Venation type
Class
Birch
Rose
Lily of the valley
Plantain
The teacher checks the completed assignment together with the students.
3. Updating knowledge on the topic of the lesson.
Roots provide plants only with water and mineral salts, but plants also need organic substances for normal growth and development. Where do these substances come from in the plant? Many scientists have tried to solve this mystery of living nature.At firstXVIV. Dutch naturalist Jan van Helmont also became interested in this issue and decided to conduct an experiment. He placed 80 kg of soil in a pot and planted a willow branch. Covered the soil in the pot to prevent dust from getting on it. I watered the branch only with rainwater, which did not contain any nutrients. After 5 years, the grown willow was taken out of the ground and weighed. Her weight increased by 65 kg over 5 years. The mass of soil in the pot decreased by only 50 g! Where did the plant get 64 kg 950 g of organic matter? Many scientists tried to solve this mystery of living nature. At firstXVIV. Dutch naturalist Jan van Helmont also became interested in this issue and decided to conduct an experiment. He placed 80 kg of soil in a pot and planted a willow branch. Covered the soil in the pot to prevent dust from getting on it. I watered the branch only with rainwater, which did not contain any nutrients. After 5 years, the grown willow was taken out of the ground and weighed. Her weight increased by 65 kg over 5 years. The mass of soil in the pot decreased by only 50 g! Where did the plant get 64 kg 950 g of organic matter?
Student responses based on knowledge and life experience.
( Plants are capable of creating organic matter themselves.)
4. Statement of the topic and purpose of the lesson.
Topic: Formation of organic substances in plants You will learn what conditions are needed for the formation of organic substances and the significance of this process for life on earth.
5. Work on the topic of the lesson.
Teacher's story, presentation, demonstration of experiments.
1. What are plants made of?
Plants contain organic and inorganic substances.
Inorganic substances, as you remember from 6th grade, are water and mineral salts.
And the organic substances that make up plants include sugar (you feel it when you eat grapes), vitamins (which are especially abundant in lemon, currants, etc.), vegetable proteins (in beans, peas, etc.)
Plant composition
Organic matter
Inorganic substances
Sugar
fat
water
Minerals
Starch
vitamins
squirrels
Finish filling out the diagram in your notebook based on the results of the experiments.
Demonstration of experiments:
Experiment 1. Detection of fat using sunflower as an example.
1. Peel a few sunflower seeds.
2. Place the seed on blotting paper.
3. Press down on the seed and remove the crushed seed.
What do you see? There is a greasy stain on the blotting paper.
Conclusion: it means that sunflower seeds contain fat.
Experiment 2. “Detection of starch.”
1. Take a potato and cut it in half.
2. Take a pipette and iodine. Place 2-3 drops of iodine on the cut potato.
What do you see? You will see a blue spot on the cut of the potato.
Conclusion: it means there is starch in potatoes.
But where do all these substances come from in plants? Does the plant take water and mineral salts from the soil? Where do organic substances come from?
2. Formation of organic substances in plants
This question was answered by the Russian scientist Kliment Arkadyevich Temiryazev.
He found that organic substances are formed in leaves.
Leaves are not only part of the shoot, but also peculiar, unique
laboratories in which organic substances are formed: sugar and starch. This
the process is perhaps the most remarkable process taking place on our
planet. Thanks to him, all life on Earth exists.
Consider a green leaf of a plant. (slide)
The leaf has a green color. This is explained by the fact that the leaf contains a green substance - chlorophyll.
Vocabulary work. Working with a biological dictionary p. 221.
A card with the word “Chlorophyll” is hung on the board.
Chlorophyll - the green substance of plants, which is located in special bodies - chloroplasts.
It is in them that organic matter is formed.But certain conditions are necessary for the formation of organic substances.
3. Conditions for the formation of organic substances by plants.
First of all, you need chlorophyll. Chlorophyll will work if light falls on the leaf. The illuminated leaf takes carbon dioxide from the air. Water enters the leaf from the roots. And this whole process occurs in the presence of heat.
Vocabulary work “Photosynthesis”
The formation of organic substances in light with the help of chlorophyll is calledphotosynthesis.
Photosynthesis - /photo-light, synthesis - formation/.
Writing in a notebook
Conditions for the formation of organic substances by plants
1 presence of chlorophyll.
2 light.
3. carbon dioxide.
4 warm.
5 water.
When all these conditions - chlorophyll, light, carbon dioxide, heat, water - are present, sugar is formed in the leaf. Some of the sugar already in the leaf turns into starch.The formation of starch in leaves is plant nutrition.
Screening of the presentation “Formation of starch in plant leaves in the light”
1. The geranium plant was placed in a dark cabinet for 3 days to allow the outflow of nutrients from the leaves.
2. Then the plant was placed in the light for 8 hours,
3. Remove the leaf of the plant and place it first in hot water(at the same time, the integumentary and main tissue of the leaf was destroyed), the leaf became softer, then we placed it in boiling alcohol. (At the same time, the leaf became discolored, and the alcohol became bright green from chlorophyll).
4. Then the discolored leaf was treated with a weak iodine solution
5. Result: the appearance of a blue color when the leaf is treated with iodine.
Conclusion: Indeed, starch has formed in the leaves.
Remember, unlike other living organisms, plants do not absorb organic substances, they synthesize them themselves.
In the process of creating organic matter, plants release oxygen.
In the 18th century In 1771, an English chemistJoseph Priestleyperformed the following experiment: he placed two mice under a glass bell, but placed a houseplant under one of the bells. Look at the illustration and say what happened to the mouse where there was no houseplant. The mouse died.
Yes, unfortunately the mouse died. Think about how you can explain the fact that the mouse under the second hood, where the houseplant was placed, remained alive?
Remember which of the following gases is necessary for living beings to breathe? Oxygen.
Right. So we answered the question why the mouse survived. The houseplant produced oxygen, and the mouse used it for breathing.
Organic substances that are produced during photosynthesis are needed to nourish all parts of the plant, from roots to flowers and fruits. The more solar energy and carbon dioxide a plant receives, the more organic matter it will produce. This is how the plant feeds, grows and gains weight.
Indeed, plants create organic substances for their own needs, but also provide food for other living organisms and provide oxygen for breathing to all living things. The vegetation cover of the earth is called the “green lungs of the planet.” Whether they remain healthy depends on you and me, on how wisely we manage the wealth given to us.
PHYSMINUTE
GYMNASTICS FOR THE EYES
Guys, listen to the words of K.A. Timiryazev “Give it yourself the best cook as much fresh air as you want, as much sunshine as you want, and a whole river of clean water, and ask him to prepare you sugar, starch, fats and grains from all this - he will think that you are laughing at him.
But what seems absolutely fantastic to man happens unhindered in green leaves.”
How do you understand this expression?
6. Primary consolidation and correction of knowledge.
What gas do green plant leaves absorb? Carbonic.
What substance enters the leaves through the vessels of the stem? Water.
Which important condition necessary? Sunlight.
What gas is emitted by green plant leaves? Oxygen.
Which complex substances are formed in the leaves. Organic matter
Give this process a name. Photosynthesis.
What is the name of the substance in which the process of photosynthesis occurs? Chlorophyll.
Draw and write down a diagram of photosynthesis
CARBON DIOXIDE + WATER = ORGANIC SUBSTANCES + OXYGEN
Photosynthesis is a process that occurs in green leaves plants in the light , at which from carbon dioxide and water are formed organic matter and oxygen.
7. Consolidation of the studied material.
(variable task)
1. Frontal survey
Guys, today in class you learned a lot of new and interesting things.
Answer the questions:
1.What process is called photosynthesis?
2.With the help of what substance does the process of photosynthesis occur in the leaves?
3. What do organic substances form in green leaves?
4. What gas is released from green leaves in the light? What is its significance for living organisms?
5 . What conditions are necessary for the process of photosynthesis?
2. Testing
"Formation of organic substances in leaves."
In what part of the plant are organic substances formed?
root;
sheet;
stem;
flower.
What conditions are necessary for the formation of organic substances in a plant?
chlorophyll, light, heat, carbon dioxide, water;
chlorophyll, heat;
carbon dioxide, water.
What gas does a plant release during the formation of starch?
nitrogen;
oxygen;
carbon dioxide.
How does a plant use organic matter?
____________________________________________________________________________________________________________________________________________________________________________________________________________
3. Card “Conditions for the formation of organic substances in plants.”
Additionalassignment.
Read the text of the letter. Find mistakes made by the author of the letter?
Correct mistakes.
Hello, young biolukhs! Greetings to you Alyosha Pereputkin. I am a great connoisseur
photosynthesis process. Oh, do you know him? otosynthesis occurs in roots and leaves,
only at night, when no one bothers you. During this process, water is produced and oxygen is consumed. The moon sends its energy and organic substances are formed in the cells.
substances: first starch, and then sugar. During the process of photosynthesis, a lot is released
energy, so plants are not afraid of the cold in winter. Without photosynthesis, we would suffocate, since there would be no enrichment of the atmosphere with carbon dioxide.
Summing up the lesson
During the lesson, you learned how plants eat and grow; it was proven that without a green leaf, not only can a plant not live, but there would be no life at all on Earth, since oxygen earth's atmosphere, which all living beings breathe, was produced during the process of photosynthesis. The great Russian botanist K.A. Timiryazev called the green leaf the great factory of life. The raw materials for it are carbon dioxide and water, the engine is light. Green plants, constantly releasing oxygen, will not allow humanity to die. And we must take care of clean air.
In rock I would like to end with poetry
Photosynthesis occurs in light all year round.
And it gives people food and oxygen.
Very important process - photosynthesis, Friends,
We cannot do without it on Earth.
Fruits, vegetables, bread, coal, hay, firewood -
Photosynthesis is the head of it all.
The air will be clean, fresh, how easy it is to breathe!
And the ozone layer will protect us.
Homework
As you know, all substances can be divided into two large categories - mineral and organic. You can cite a large number of examples of inorganic, or mineral, substances: salt, soda, potassium. But what types of connections fall into the second category? Organic substances are present in any living organism.
Squirrels
The most important example of organic substances are proteins. They contain nitrogen, hydrogen and oxygen. In addition to these, sometimes sulfur atoms can also be found in some proteins.
Proteins are among the most important organic compounds and are the most commonly found in nature. Unlike other compounds, proteins have some character traits. Their main property is their huge molecular weight. For example, the molecular weight of an alcohol atom is 46, benzene is 78, and hemoglobin is 152,000. Compared to the molecules of other substances, proteins are real giants, containing thousands of atoms. Sometimes biologists call them macromolecules.
Proteins are the most complex of all organic structures. They belong to the class of polymers. If you examine a polymer molecule under a microscope, you can see that it is a chain consisting of simpler structures. They are called monomers and are repeated many times in polymers.
In addition to proteins, there are a large number of polymers - rubber, cellulose, as well as ordinary starch. Also, many polymers were created by human hands - nylon, lavsan, polyethylene.
Protein formation
How are proteins formed? They are an example of organic substances, the composition of which in living organisms is determined by genetic code. In their synthesis, in the vast majority of cases, various combinations are used
Also, new amino acids can be formed already when the protein begins to function in the cell. However, it contains only alpha amino acids. The primary structure of the substance being described is determined by the sequence of amino acid residues. And in most cases, when a protein is formed, the polypeptide chain is twisted into a spiral, the turns of which are located close to each other. As a result of the formation of hydrogen compounds, it has a fairly strong structure.
Fats
Another example of organic substances is fats. Man knows many types of fats: butter, beef and fish oil, vegetable oils. IN large quantities fats are formed in plant seeds. If you place a peeled sunflower seed on a sheet of paper and press it down, an oily stain will remain on the sheet.
Carbohydrates
Carbohydrates are no less important in living nature. They are found in all plant organs. The carbohydrate class includes sugar, starch, and fiber. Potato tubers and banana fruits are rich in them. It is very easy to detect starch in potatoes. When reacting with iodine, this carbohydrate turns blue. You can verify this by dropping a little iodine onto a cut potato.
Sugars are also easy to detect - they all taste sweet. Many carbohydrates of this class are found in the fruits of grapes, watermelons, melons, and apples. They are examples of organic substances that are also produced in artificial conditions. For example, sugar is extracted from sugar cane.
How are carbohydrates formed in nature? The most simple example is the process of photosynthesis. Carbohydrates are organic substances that contain a chain of several carbon atoms. They also contain several hydroxyl groups. During photosynthesis, inorganic sugar is formed from carbon monoxide and sulfur.
Cellulose
Another example of organic matter is fiber. Most of it is found in cotton seeds, as well as plant stems and their leaves. Fiber consists of linear polymers, its molecular weight ranges from 500 thousand to 2 million.
In its pure form, it is a substance that has no smell, taste or color. It is used in the manufacture of photographic film, cellophane, and explosives. Fiber is not absorbed by the human body, but is a necessary part of the diet, as it stimulates the functioning of the stomach and intestines.
Organic and inorganic substances
We can give many examples of the formation of organic and second always originating from minerals - non-living ones that are formed in the depths of the earth. They are also found in various rocks.
Under natural conditions, inorganic substances are formed during the destruction of minerals or organic substances. On the other hand, organic substances are constantly formed from minerals. For example, plants absorb water with compounds dissolved in it, which subsequently move from one category to another. Living organisms use mainly organic substances for nutrition.
Reasons for diversity
Often, schoolchildren or students need to answer the question of what are the reasons for the diversity of organic substances. The main factor is that carbon atoms are connected to each other using two types of bonds - simple and multiple. They can also form chains. Another reason is the variety of different chemical elements that are found in organic matter. In addition, diversity is also due to allotropy - the phenomenon of the existence of the same element in different compounds.
How are inorganic substances formed? Natural and synthetic organic substances and their examples are studied both in high school and in specialized higher education. educational institutions. The formation of inorganic substances is not such a complex process as the formation of proteins or carbohydrates. For example, people have been extracting soda from soda lakes since time immemorial. In 1791, chemist Nicolas Leblanc proposed synthesizing it in the laboratory using chalk, salt, and sulfuric acid. Once upon a time, soda, which is familiar to everyone today, was a rather expensive product. To carry out the experiment it was necessary to calcinate table salt together with acid, and then calcinate the resulting sulfate along with limestone and charcoal.
Another is potassium permanganate, or potassium permanganate. This substance is obtained industrially. The formation process consists of electrolysis of a solution of potassium hydroxide and a manganese anode. In this case, the anode gradually dissolves to form a purple solution - this is the well-known potassium permanganate.
summary of other presentations“Culture of plant cells and tissues” - Functions of hormones in callusogenesis. Factors influencing synthesis. Differentiated cells. Types of cell and tissue cultures. Genetic heterogeneity. Plant cell cultures. Dedifferentiation. Characteristics of callus cells. Historical aspects. Formation of crown galls. Single cell culture. Reasons for asynchrony. Synthesis of secondary metabolites. Differentiation of callus tissues. Physical factors.
“Plant leaves” - Petiolate leaves. What is the edge of the leaf blade? The leaf is also the organ of respiration, evaporation and guttation (excretion of water droplets) of the plant. What type of venation? Compound leaves. Describe the leaf. The leaves are located on both sides of the petiole at some distance from each other. Sessile leaves. The edge of the leaf blade. Trisyllabic. Opposite. Whorled. Veins. Simple leaves. In botany, a leaf is an external organ of a plant whose main function is photosynthesis.
“Classification of fruits” - Pumpkin. Pomeranian. Classification of fruits. Organs of flowering plants. Compare. Berry. Apple. Juicy fruits. Find the odd one out. Polydrupe. Consolidation of the studied material. Drupe. Pericarp. Reproductive organs. Fruits, their classification.
“Fruits and Seeds” - Pod. Don't let your soul be lazy. Laboratory work. Pumpkin. Caryopsis. Knowledge. Drupe. Transfer. Tree of knowledge. Questions for consolidation. Spread by scattering. Spread by water. Signs of seeds. Infertility. An inconspicuous flower. Transfer on external integuments. Fetal formation. Box. Work in groups. Polydrupe. Fetus. Spread by wind. Why do seeds need to disperse?
“Structure of the shoot” - Tuber. Types of kidneys. Formed from buds at the base of the stem. External structure of the shoot. Organic substances. Internal structure. Development of shoot from the bud. Internodes are clearly defined. The escape. Root tuber. Stem growth. Stem. Escape modifications. Variety of shoots. Corm. Transport of substances along the stem. Rhizome. Bulb. Branching. Bulb and corm. Scales. Bud.
“Tasks on the structure of plants” - Location of vascular bundles. Look at the picture and answer the questions. Horizontal transport. Underground modifications of shoots. The structure of the kidneys. Location of shoots in space. Plant tissues. Branching of shoots. Structure of the growth cone. External structure of the root. Tillering. Root modifications. Look at the drawing. Didactics for an interactive whiteboard in biology. Leaf arrangement.
