Option 1
Part A
1.
b) the presence of catalysts;
d) metabolic processes.
2.
a) anaerobic heterotrophs;
b) aerobic heterotrophs;
c) autotrophs;
d) symbiont organisms.
3. To this general property living, as self-regulation, refers to:
a) heredity;
b) variability;
c) irritability;
d) ontogeny.
4. The essence of the theory of abiogenesis is:
c) the creation of the world by God;
5. A crystal is not a living system because:
a) he is not capable of growth;
c) he is not characterized by irritability;
6. Louis Pasteur's experiments proved the possibility of:
a) spontaneous generation of life;
d) biochemical evolution.
7.
a) radioactivity;
b) the presence of liquid water;
c) the presence of gaseous oxygen;
d) mass of the planet.
8. Carbon is the basis of life on Earth, because... He:
9. Eliminate unnecessary things:
a) 1668;
b) F. Redi;
c) meat;
d) bacteria.
10.
a) L. Pasteur;
b) A. Levenguk;
c) L. Spallanzani;
d) F. Redi.
Part B
Complete the sentences.
1. The theory postulating the creation of the world by God (the Creator) is….
2. Prenuclear organisms that do not have a nucleus limited by a shell and organelles capable of self-reproduction are ....
3. A phase-separated system interacting with the external environment according to the type open system, – … .
4. The Soviet scientist who proposed the coacervate theory of the origin of life is ....
5. The process by which an organism acquires a new combination of genes is….
Part B
Give brief answers to the following questions.
1. What are the common characteristics of living and nonliving matter?
2. Why should there be no oxygen in the Earth's atmosphere when the first living organisms arose?
3. What was Stanley Miller's experience? What corresponded to the “primary ocean” in this experience?
4. What is the main problem of the transition from chemical to biological evolution?
5. List the main provisions of A.I. Oparin’s theory.
Option 2
Part A
Write down the numbers of the questions and write down the letters of the correct answers next to them.
1. Living things differ from non-living things:
a) the composition of inorganic compounds;
c) interaction of molecules with each other;
d) metabolic processes.
2. The first living organisms on our planet were:
a) anaerobic heterotrophs;
b) aerobic heterotrophs;
c) autotrophs;
d) symbiont organisms.
3.
a) metabolism;
b) reproduction;
c) irritability;
d) ontogeny.
4. The essence of the theory of biogenesis is:
a) the origin of living things from non-living things;
b) the origin of living things from living things;
c) the creation of the world by God;
d) the introduction of life from Space.
5. A star is not a living system because:
a) she is not capable of growth;
c) she is not irritable;
6.
a) spontaneous generation of life;
b) the emergence of living things only from living things;
c) bringing in “seeds of life” from Space;
d) biochemical evolution.
7. Of these conditions, the most important for the emergence of life is:
a) radioactivity;
b) availability of water;
c) availability of an energy source;
d) mass of the planet.
8. Water is the basis of life because:
a) is a good solvent;
d) has all of the listed properties.
9. Eliminate unnecessary things:
a) 1924;
b) L. Pasteur;
c) meat broth;
d) bacteria.
10. Place the following names in logical order:
a) L. Pasteur;
b) S. Miller;
c) J. Haldane;
d) A.I. Oparin.
Part B
Complete the sentences.
1. The process of formation by living organisms organic molecules from inorganic ones due to the energy of sunlight –….
2. Precellular formations that had some properties of cells (the ability to metabolize, self-reproduce, etc.) - ....
3. Separation of a protein solution containing other organic substances into phases with a higher or lower concentration of molecules - ....
4. English physicist who suggested that adsorption was one of the stages of concentration organic matter in the course of prebiological evolution –….
5. A system characteristic of all living organisms for recording hereditary information in DNA molecules in the form of a sequence of nucleotides - ....
Part B
1. What was Stanley Miller's experience? What corresponded to the “lightning” in this experience?
2. Why should the mass of a planet on which life can arise not be more than 1/20 the mass of the Sun?
3. To what stage of the development of life on Earth can the words of Gogol’s hero be attributed: “I don’t remember the date. It wasn't a month either. What the hell was that?”
4. What conditions are necessary for life to arise?
5. What is panspermia? Which of the scientists you know adhered to this theory?
Option 3
Part A
Write down the numbers of the questions and write down the letters of the correct answers next to them.
1. Living things differ from non-living things:
a) the composition of inorganic compounds;
b) the ability to reproduce itself;
c) interaction of molecules with each other;
d) metabolic processes.
2. The first living organisms on our planet were:
a) anaerobic heterotrophs;
b) aerobic heterotrophs;
c) autotrophs;
d) symbiont organisms.
3. Such a general property of living things as self-renewal includes:
a) metabolism;
b) reproduction;
c) irritability;
d) ontogeny.
4. The essence of creationism is:
a) the origin of living things from non-living things;
b) the origin of living things from living things;
c) the creation of the world by God;
d) the introduction of life from Space.
5. A river is not a living system because:
a) she is not capable of growth;
b) she is not capable of reproduction;
c) she is not capable of irritability;
d) not all properties of living things are inherent in it.
6. Francesco Redi's experiment proved the impossibility:
a) spontaneous generation of life;
b) the emergence of living things only from living things;
c) introducing “seeds of life” from space;
d) biochemical evolution.
7. Of these conditions, the most important for the emergence of life is:
a) radioactivity;
b) availability of water;
c) an infinitely long evolutionary time;
8. During the period of the emergence of life, there should have been no oxygen in the Earth’s atmosphere, because:
a) it is an active oxidizing agent;
b) has a high heat capacity;
c) increases its volume when frozen;
d) all of the above in combination.
9. Eliminate unnecessary things:
a) 1953;
b) bacteria;
c) S. Miller;
d) abiogenic synthesis.
10.
a) L. Pasteur;
b) F. Redi;
c) L. Spallanzani;
d) A.I. Oparin.
Part B
Complete the sentences.
1. The formation of organic molecules from inorganic ones outside living organisms - ....
2. Liquid bubbles surrounded by protein films that arise when shaking aqueous solutions of proteins are ....
3. The ability to reproduce similar biological systems, which manifests itself at all levels of organization of living matter, is ....
4. The American scientist who proposed the thermal theory of the origin of protobiopolymers is ....
5. Protein molecules that accelerate the course of biochemical transformations in aqueous solutions at atmospheric pressure, –….
Part B
Give a short answer to the question asked.
1. What is the main difference between the burning of wood and the “burning” of glucose in cells?
2. What are three modern points of view on the problem of the origin of life?
3. Why is carbon the basis of life?
4. What was Stanley Miller's experience?
5. What are the main stages of chemical evolution?
Option 4
Part A
Write down the numbers of the questions and write down the letters of the correct answers next to them.
1. Living things differ from non-living things:
a) the composition of inorganic compounds;
b) the ability to self-regulate;
c) interaction of molecules with each other;
d) metabolic processes.
2. The first living organisms on our planet were:
a) anaerobic heterotrophs;
b) aerobic heterotrophs;
c) autotrophs;
d) symbiont organisms.
3. Such a general property of living things as self-reproduction includes:
a) metabolism;
b) reproduction;
c) irritability;
d) ontogeny.
4. The essence of the panspermia theory is:
a) the origin of living things from non-living things;
b) the origin of living things from living things;
c) the creation of the world by God;
d) bringing “seeds of life” to Earth from Space.
5. A glacier is not a living system because:
a) he is not capable of growth;
b) he is not capable of reproduction;
c) he is incapable of irritability;
d) not all properties of a living thing are inherent to it.
6. The experiment of L. Spallanzani proved the impossibility:
a) spontaneous generation of life;
b) the emergence of living things only from living things;
c) bringing in “seeds of life” from Space;
d) biochemical evolution.
7. Of these conditions, the most important for the emergence of life is:
a) radioactivity;
b) availability of water;
c) the presence of certain substances;
d) a certain mass of the planet.
8. Carbon is the basis of life because... He:
a) is the most common element on Earth;
b) the first of the chemical elements began to interact with water;
c) has a low atomic weight;
d) capable of forming stable compounds with double and triple bonds.
To be continued
The process of formation by living organisms of organic molecules from inorganic ones using energy
The initial substances of photosynthesis - carbon dioxide and water on the earth's surface are neither oxidizing nor reducing agents. During photosynthesis, this “neutral environment” bifurcates into opposites: strong oxidizing agent– free oxygen and strong reducing agents – organic compounds (outside plant organisms, the decomposition of carbon dioxide and water is possible only with high temperature, for example, in magma or in blast furnaces, etc.).
Carbon and hydrogen of organic compounds, as well as free oxygen released during photosynthesis, were “charged” with solar energy, rose to a higher energy level, and became “geochemical batteries”.
Carbohydrates and other products of photosynthesis, moving from leaves to stems and roots, enter into complex reactions, during which the entire variety of organic compounds of plants is created.
However, plants consist not only of carbon, hydrogen and oxygen, but also of nitrogen, phosphorus, potassium, calcium, iron and other chemical elements, which they receive in the form of relatively simple mineral compounds from soil or water bodies.
Absorbed by plants, these elements become part of complex energy-rich organic compounds (nitrogen and sulfur - into proteins, phosphorus - into nucleoproteins, etc.) and also become geochemical batteries.
This process is called biogenic accumulation of mineral compounds. Thanks to biogenic accumulation, elements from water and air pass into a less mobile state, that is, their migration ability decreases. All other organisms are animals, the vast majority of microorganisms and chlorophyll-free plants (for example, fungi) are heterotrophs, i.e. they are not capable of creating organic substances from mineral ones.
They obtain organic compounds needed to build their bodies and as a source of energy from green plants.
The process of photosynthesis occurs in unity with the work of the root system, which supplies water and nutrients to the leaf.
There are a number of hypotheses explaining the mechanism of ion entry through the root system: by diffusion, adsorption, metabolic transfer of substances against an electrochemical gradient. All hypotheses are based on the statement about the exchange of ions between the root system and the soil. At the same time, the root system, like the leaf, is a laboratory of synthesis. Plants primarily absorb those substances through their root system. chemical elements that perform necessary functions in the body.
Other elements penetrate mechanically in accordance with their concentration gradient. Simultaneously with the release of nutritional elements, the root system releases various metabolic products into the soil. Among them, organic acids (citric, malic, oxalic, etc.) perform an important function.
As a result of dissociation, hydrogen ions are released, which acidify the soil reaction, thereby accelerating the dissolution of minerals and releasing chemical elements for plant nutrition.
Other metabolic products are used in the vital activity of certain types of microorganisms, which are also involved in the destruction of minerals.
Cations and anions that enter plants through the root system are distributed in organs and tissues, enter organic and mineral compounds, and perform various functions. physiological function: maintain osmotic pressure, alkaline-acid balance, used as a plastic material, an integral part of enzymes, chlorophyll, etc. During the metabolic process, there is a continuous formation of acidic compounds.
The breakdown of carbohydrates produces pyruvic and lactic acids, the breakdown of fatty acids produces butyric and acetoacetic acids, and the breakdown of proteins produces sulfuric and phosphoric acids. Excessive accumulation of acids is neutralized by buffer compounds, which convert them into compounds that are easily removed from the body.
The synthesis of organic matter occurs not only through the use of radiant energy from the sun by green plants.
Bacteria are known that use for this purpose the energy released during the oxidation of certain inorganic compounds (In 1890.
S.P. Vinogradsky discovered microorganisms capable of oxidizing ammonia to nitrous salts and then nitric acids). This process of creating organic substances is called chemosynthesis. Chemosynthetic bacteria are typical autotrophs, i.e. independently synthesized from inorganic substances necessary organic compounds (carbohydrates, proteins, lipids, etc.) the most important group of chemosynthetic microorganisms are nitrifying bacteria.
They oxidize ammonia formed during the decay of organic residues to nitric acid. Chemosynthetic bacteria include sulfur-, iron-, methane-, carbon bacteria, etc. For example, in the soils of floodplains, bog iron ore is often found in the form of durable nodules of various shapes and sizes; it is formed with the participation of iron bacteria.
Under the influence of iron bacteria, ferrous iron is converted into oxide iron. The resulting iron hydroxide precipitates and forms bog iron ore.
V.G. SMELOVA,
biology teacher
Municipal educational institution secondary school No. 7, Noyabrsk
End. See No. 9/2006
Test on the topic:
"The Origin of Life on Earth"
9. Eliminate unnecessary things:
a) DNA;
b) genetic code;
c) chromosome;
d) cell membrane.
Test on the topic: Hypotheses of the origin of life on Earth
Place the following names in logical order:
a) A.I. Oparin;
b) L. Pasteur;
c) S. Miller;
d) J. Haldane.
Part B
Complete the sentences.
1. Organisms that have a nucleus limited by a shell, have self-reproducing organelles, internal membranes and a cytoskeleton - ....
A system characteristic of all organisms for recording hereditary information in DNA molecules in the form of a sequence of nucleotides - ....
3. The ability to reproduce biologically similar systems, manifested at all levels of organization of living matter, is ....
The creators of the low-temperature theory of the origin of protobiopolymers are ....
5. Precellular formations that had some properties of cells: the ability to metabolize, self-reproduce, etc., - ....
Part B
Give a short answer to the question asked.
1. What role did the study of meteorites play in the development of the theory of the origin of life?
2. What are racemization and chirality?
Why was water in the liquid phase a necessary condition for the emergence of life?
4. What was Stanley Miller's experience? What was gas composition"atmosphere"?
5. What are the main stages in studying the question of the origin of life on Earth?
Answers
Option 1
Part A: 1d, 2a, 3c, 4a, 5d, 6b, 7b, 8d, 9d, 10d, b, c, a.
Part B: 1 – creationism; 2 – prokaryotes; 3 – coacervate; 4 – A.I.
Oparin; 5 – sexual process.
Part B.
1. Living and nonliving matter consist of the same chemical elements; physical and chemical processes with their participation proceed according to general laws.
Oxygen is a strong oxidizing agent, and all newly formed organic molecules would be immediately oxidized.
3.
The “primary ocean” in this experiment corresponded to a flask with boiling water.
4. The main problem of the transition from chemical to biological evolution is to explain the emergence of self-reproducing biological systems (cells) in general and the genetic code in particular.
The main provisions of Oparin's theory:
– life is one of the stages of the evolution of the Universe;
– the emergence of life is a natural result of the chemical evolution of carbon compounds;
– for the transition from chemical evolution to biological evolution, the formation and natural selection integral, isolated from the environment, but constantly interacting with it multimolecular systems.
Option 2
Part A: 1 b, d, 2a, 3b, 4b, 5d, 6a, 7b, 8d, 9a, 10 a, d, c, b.
Part B: 1 – photosynthesis; 2 – protobionts; 3 – coacervation; 4 – J. Bernal; 5 – genetic code.
Part B.
1. In 1953, S. Miller created an experimental installation in which the conditions of the primordial Earth were simulated and molecules of biologically important organic compounds were obtained through abiogenic synthesis. “Lightning” in this experiment was simulated by high-voltage electrical discharges.
2. If the mass of a planet is more than 1/20 the mass of the Sun, intense nuclear reactions begin on it, which increases its temperature, and it begins to glow with its own light.
3. TO initial stage biochemical evolution of the Earth.
4. For life to arise, the following basic conditions are necessary:
– presence of certain chemicals(including water in the liquid phase);
– availability of energy sources;
– restorative atmosphere.
Additional conditions may include the mass of the planet and a certain level of radioactivity.
Panspermia is the introduction of “seeds of life” to Earth from space. Supporters: J. Liebig, G. Helmholtz, S. Arrhenius, V.I. Vernadsky.
Option 3
Part A: 1 b, d, 2a, 3a, 4c, 5d, 6a, 7b, 8a, 9b, 10 b, c, a, d.
Part B: 1 – abiogenic synthesis; 2 – microspheres; 3 – self-reproduction; 4 – S.Fox; 5 – enzymes.
Part B.
1. When wood burns, all the energy released is dissipated in the form of light and heat. When glucose is oxidized in cells, energy is stored in high-energy bonds of ATP.
2. There are three main approaches to the problem of the origin of life:
– there is no problem, because
life was either created by God (creationism) or has existed in the Universe since its origin and spread randomly (panspermia);
– the problem is insoluble due to insufficient knowledge and the impossibility of reproducing the conditions in which life arose;
– the problem can be solved (A.I.
Oparin, J. Bernal, S. Fox, etc.).
3. Carbon is tetravalent, capable of forming stable compounds with double and triple bonds, which increases reactivity its connections.
4. In 1953, S. Miller created an experimental installation in which the conditions of the primordial Earth were simulated and molecules of biologically important organic compounds were obtained through abiogenic synthesis.
Atoms ––> simple chemical compounds––> simple bioorganic compounds ––> macromolecules ––> organized systems.
Option 4
Part A: 1 b, d, 2a, 3b, 4d, 5d, 6a, 7c, 8d, 9d, 10 b, a, d, c.
Part B: 1 – eukaryotes; 2 – genetic code; 3 – self-reproduction; 4 – C. Simonescu, F. Denes; 5 – protobionts.
Part B.
1. Analysis of the chemical composition of meteorites showed that some of them contain amino acids (glutamic acid, proline, glycine, etc.) and fatty acids (17 types).
Thus, organic matter is not exclusively a property of the Earth, but can also be found in space.
2. Racemization is the reaction of interconversion of the D- and L-forms of any stereoisomer; chirality is the existence of two or more mirror-image asymmetric stereoisomers of a chemical compound.
3. Organisms consist of 80% water or more.
4. In 1953, S. Miller created an experimental installation in which the conditions of the primordial Earth were simulated and molecules of biologically important organic compounds were obtained through abiogenic synthesis.
Gas composition of the “atmosphere”: methane, ammonia, water vapor, hydrogen.
5. From ancient times to the experiments of F. Redi - a period of universal belief in the possibility of spontaneous generation of living things; 1668–1862 (before the experiments of L. Pasteur) - experimental clarification of the impossibility of spontaneous generation; 1862–1922 (before A.I. Oparin’s speech) – philosophical analysis of the problem; 1922–1953 – development of scientific hypotheses about the origin of life and their experimental testing; since 1953
up to now - experimental and theoretical studies of the paths of transition from chemical evolution to biological.
Note
Answers in Part A are worth 1 point, Part B - 2 points, Part C - 3 points.
Maximum points for test work – 35.
Score 5: 26–35 points;
score 4: 18–25 points;
score 3: 12–17 points;
score 2: less than 12 points.
Biology
Textbook for grades 10-11
Section I. A cell is a unit of living things
Chapter I. Chemical composition of the cell
Chapter I. Chemical composition of the cell
Living organisms contain a large number of chemical elements. They form two classes of compounds - organic and inorganic.
Chemistry48.Ru
Chemical compounds, the basis of which are carbon atoms, constitute the hallmark of living things. These compounds are called organic.
Organic compounds are extremely diverse, but only four classes have universal biological significance: proteins, nucleic acids, carbohydrates and lipids.
§ 1. Inorganic compounds
Biologically important chemical elements. Of the more than 100 chemical elements known to us, about 80 are included in living organisms, and only 24 are known what functions they perform in the cell. The set of these elements is not accidental.
Life originated in the waters of the World Ocean, and living organisms consist primarily of those elements that form compounds that are easily soluble in water. Most of these elements are light; their peculiarity is the ability to form strong (covalent) bonds and form many different complex molecules.
The composition of human body cells is dominated by oxygen (more than 60%), carbon (about 20%) and hydrogen (about 10%).
Nitrogen, calcium, phosphorus, chlorine, potassium, sulfur, sodium, magnesium taken together account for about 5%. The remaining 13 elements make up no more than 0.1%. The cells of most animals have a similar elemental composition; Only the cells of plants and microorganisms differ. Even those elements that are contained in cells in negligible quantities cannot be replaced by anything and are absolutely necessary for life. Thus, the iodine content in cells does not exceed 0.01%. However, if there is a lack of it in the soil (because of this and in food products) the growth and development of children is delayed.
The meaning for the basic element cell is given at the end of this paragraph.
Inorganic (mineral) compounds. The composition of living cells includes a number of relatively simple compounds that are also found in inanimate nature - in minerals and natural waters.
These are inorganic compounds.
Water is one of the most common substances on Earth. It covers most of the earth's surface. Almost all living things are composed primarily of water. In humans, the water content in organs and tissues varies from 20% (in bone tissue) to 85% (in the brain). About 2/3 of a person’s mass is water, in the body of a jellyfish up to 95% is water, even in dry plant seeds, water is 10-12%.
Water has some unique properties.
These properties are so important for living organisms that it is impossible to imagine life without this compound of hydrogen and oxygen.
The unique properties of water are determined by the structure of its molecules. In a water molecule, one oxygen atom is covalently bonded to two hydrogen atoms (Fig. 1). The water molecule is polar (dipole). Positive charges are concentrated on hydrogen atoms, since oxygen is more electronegative than hydrogen.
Rice. 1. Formation of hydrogen bonds in water
The negatively charged oxygen atom of one water molecule is attracted to the positively charged hydrogen atom of another molecule to form a hydrogen bond (Fig.
The strength of a hydrogen bond is approximately 15-20 times weaker than a covalent bond. Therefore, the hydrogen bond is easily broken, which is observed, for example, during the evaporation of water. Due to the thermal movement of molecules in water, some hydrogen bonds are broken and others are formed.
Thus, in liquid water the molecules are mobile, which is important for metabolic processes. Water molecules easily penetrate cell membranes.
Due to the high polarity of its molecules, water is a solvent for other polar compounds. More substances dissolve in water than in any other liquid. That is why in aquatic environment cells carried many chemical reactions. Water dissolves metabolic products and removes them from the cell and the body as a whole.
Water has a high heat capacity, i.e. the ability to absorb heat with a minimal change in its own temperature. Thanks to this, it protects the cell from sudden changes in temperature. Since a lot of heat is consumed to evaporate water, by evaporating water, organisms can protect themselves from overheating (for example, when sweating).
Water has high thermal conductivity. This property creates the possibility of uniform distribution of heat between body tissues.
Water serves as a solvent for “lubricants”, which are needed wherever there are rubbing surfaces (for example, in joints).
Water has its maximum density at 4°C.
Therefore, ice, which has a lower density, is lighter than water and floats on its surface, which protects the reservoir from freezing.
In relation to water, all cell substances are divided into two groups: hydrophilic - “loving water” and hydrophobic - “afraid of water” (from the Greek “hydro” - water, “phileo” - love and “phobos” - fear).
Hydrophilic substances include substances that are highly soluble in water. These are salts, sugars, amino acids. Hydrophobic substances, on the contrary, are practically insoluble in water.
These include, for example, fats.
Cell surfaces that separate the cell from the external environment, and some other structures, consist of water-insoluble (hydrophobic) compounds. Thanks to this, the structural integrity of the cell is maintained. Figuratively, a cell can be represented as a vessel with water, where biochemical reactions take place that ensure life. The walls of this vessel are insoluble in water. However, they are capable of selectively permeating water-soluble compounds.
In addition to water, among the inorganic substances of the cell we should mention salts, which are ionic compounds. They are formed by cations of potassium, sodium, magnesium and other metals and anions of hydrochloric, carbonic, sulfuric, and phosphoric acids. When such salts dissociate, cations (K+, Na+, Ca2+, Mg2+, etc.) and anions (CI-, HCO3-, HS04-, etc.) appear in solutions.
The concentration of ions on the outer surface of the cell is different from their concentration on the inner surface. The different numbers of potassium and sodium ions on the inner and outer surfaces of the cell create a charge difference on the membrane.
On the outer surface of the cell membrane there is a very high concentration of sodium ions, and on the inner surface there is a very high concentration of potassium ions and a low concentration of sodium. As a result, a potential difference is formed between the inner and outer surfaces of the cell membrane, which causes the transmission of excitation along a nerve or muscle.
Calcium and magnesium ions are activators of many enzymes, and their deficiency disrupts vital processes in cells. A number of important functions are performed in living organisms by inorganic acids and their salts. Hydrochloric acid creates an acidic environment in the stomach of animals and humans and in special organs of insectivorous plants, accelerating the digestion of food proteins.
Phosphoric acid residues (H3P04), joining a number of enzymatic and other cell proteins, change their physiological activity.
Residues of sulfuric acid, joining foreign substances insoluble in water, give them solubility and thus contribute to their removal from cells and organisms. Sodium and potassium salts of nitrous and phosphoric acids, calcium salt of sulfuric acid are important components mineral nutrition of plants, they are applied to the soil as fertilizers to feed plants. The meaning of chemical elements for a cell is given in more detail below.
Biologically important chemical elements of the cell
- What is the biological role of water in a cell?
- What ions are contained in the cell? What is their biological role?
- What role do the cations contained in the cell play?
The process of formation of the first organic compounds on Earth is called chemical evolution. It preceded biological evolution. The stages of chemical evolution were identified by A.I. Oparin.
Stage I is non-biological, or abiogenic (from the Greek u, un - negative particle, bios - life, genesis - origin). At this stage, chemical reactions took place in the Earth's atmosphere and in the waters of the primary ocean, saturated with various inorganic substances, under conditions of intense solar radiation. During these reactions, simple organic substances could be formed from inorganic substances - amino acids, alcohols, fatty acids, nitrogenous bases.
The possibility of synthesizing organic substances from inorganic ones in the waters of the primary ocean was confirmed in the experiments of the American scientist S. Miller and domestic scientists A.G. Pasynsky and T.E. Pavlovskaya.
Miller designed an installation in which a mixture of gases was placed - methane, ammonia, hydrogen, water vapor. These gases could have been part of the primary atmosphere. In another part of the apparatus there was water, which was brought to a boil. Gases and water vapor circulating in the apparatus under high pressure were exposed to electrical discharges for a week. As a result, about 150 amino acids were formed in the mixture, some of which are part of proteins.
Subsequently, the possibility of synthesizing other organic substances, including nitrogenous bases, was experimentally confirmed.
Stage II - synthesis of proteins - polypeptides that could be formed from amino acids in the waters of the primary ocean.
Stage III- the appearance of coacervates (from the Latin coacervus - clot, heap). Protein molecules that are amphoteric, under certain conditions, can spontaneously concentrate and form colloidal complexes, which are called coacervates.
Coacervate droplets are formed when two different proteins are mixed. A solution of one protein in water is transparent. When different proteins are mixed, the solution becomes cloudy; under a microscope, drops floating in the water can be seen in it. Such drops—coacervates—could have arisen in the waters of the primordial ocean, where various proteins were located.
Some properties of coacervates are externally similar to the properties of living organisms. For example, they "absorb" from environment and selectively accumulate certain substances and increase in size. It can be assumed that substances inside the coacervates entered into chemical reactions.
Because chemical composition"broth" in different parts The primary ocean was different, the chemical composition and properties of the coacervates were different. Competitive relationships for substances dissolved in the “broth” could have formed between coacervates. However, coacervates cannot be considered living organisms, since they lacked the ability to reproduce their own kind.
Stage IV - the emergence of molecules nucleic acids, capable of self-reproduction.
Research has shown that short chains of nucleic acids are capable of doubling without any connection with living organisms - in a test tube. The question arises: how did the genetic code appear on Earth?
The American scientist J. Bernal (1901-1971) proved that minerals played a large role in the synthesis of organic polymers. It has been shown that a number of rocks and minerals - basalt, clay, sand - have information properties, for example, the synthesis of polypeptides can be carried out on clays.
Apparently, initially a “mineralogical code” arose on its own, in which the role of “letters” was played by aluminum, iron, and magnesium cations, alternating in various minerals in a certain sequence. Three-, four- and five-letter codes appear in minerals. This code determines the sequence of amino acids joining into a protein chain. Then the role of the information matrix passed from minerals to RNA, and then to DNA, which turned out to be more reliable for the transmission of hereditary characteristics.
However, the processes of chemical evolution do not explain how living organisms arose. The processes that led to the transition from nonliving to living were called biopoiesis by J. Bernal. Biopoiesis includes stages that must have preceded the appearance of the first living organisms: the appearance of membranes in coacervates, metabolism, the ability to reproduce themselves, photosynthesis, and oxygen respiration.
The appearance of the first living organisms could have been caused by the formation of cell membranes by the alignment of lipid molecules on the surface of coacervates. This ensured the stability of their shape. The inclusion of nucleic acid molecules in the coacervates ensured their ability to self-replicate. In the process of self-reproduction of nucleic acid molecules, mutations arose, which served as material for.
So, on the basis of coacervates, the first living beings could arise. They apparently were heterotrophs and fed on energy-rich, complex organic substances contained in the waters of the primordial ocean.
As the number of organisms increased, competition between them intensified, as the supply of nutrients in the ocean waters decreased. Some organisms have acquired the ability to synthesize organic substances from inorganic ones using solar energy or the energy of chemical reactions. This is how autotrophs arose, capable of photosynthesis or chemosynthesis.
The first organisms were anaerobes and obtained energy through oxygen-free oxidation reactions such as fermentation. However, the advent of photosynthesis led to the accumulation of oxygen in the atmosphere. The result was respiration, an oxygen-based, aerobic oxidation pathway that is about 20 times more efficient than glycolysis.
Initially, life developed in the ocean waters, since strong ultraviolet radiation had a detrimental effect on organisms on land. The appearance of the ozone layer as a result of the accumulation of oxygen in the atmosphere created the preconditions for living organisms to reach land.
OPEN LESSON
“THE ORIGIN OF LIFE ON EARTH
Goals: 1. To provide knowledge about the origin of life on Earth.
2. Formation of a scientific worldview and a sense of patriotism among students.
3. Develop skills independent work and responsibility.
Testing for the lesson: “The emergence of life on Earth”
1.Where did the first inorganic compounds arise?
a) in the bowels of the Earth;
b) in the primary ocean;
c) in the primary atmosphere.
2. What was the prerequisite for the emergence of the primary ocean?
a) cooling of the atmosphere;
b) land subsidence;
c) the appearance of underground sources.
3. What were the first organic substances that arose in the ocean waters?
a) proteins;
b) fats;
c) carbohydrates;
d) nucleic reactions.
4. What properties did coacervates have?
a) growth;
b) metabolism;
c) reproduction.
5. Louis Pasteur proved with his experiments:
a) spontaneous generation of life is possible;
b) the impossibility of spontaneous generation of life.
Lesson topic: Evolutionary teaching
Lesson objectives:
1. Introducing students to the principles of historicism in the development of evolutionary ideas.
2. Formation of knowledge about evolution
3. Formation of a scientific worldview among students
Lesson Plan
Introducing students to the history of the evolutionary process
Evolutionary hypotheses of Zh.B. Lamarck
Presentation of the evolutionary teachings of Charles Darwin
Equipment: portraits of J.B. Lamarck, C. Darwin.
Lesson progress
1. Repetition of what has been learned:
– What levels of life organization did you learn in the last lesson?
– What does the subject “General Biology” study?
2. Study new topic:
Currently, science knows about 3.5 million species of animals and 600 thousand plants, 100 thousand fungi, 8 thousand bacteria and 800 types of viruses. And along with the extinct ones, throughout the history of the Earth, at least 1 billion species of living organisms lived on it.
–I just told you the word “species” - what does it mean?
– Have you studied plants and animals? Name 5 species of each?
– How did so many species arise?
– Can someone say that they were created by God? Others find the answer in scientific theory
evolution of living nature.
When studying the doctrine of evolution, there is a need to consider it in development.
How did this teaching develop?
Let us examine the very concept of “Evolution” - (lat.evolutio - deployment ). It was first used in biology by the Swiss naturalist C. Bonnet. Sounds close to this wordrevolution.
You know this word. What does it mean?
Revolution – a radical change, an abrupt transition from one state to another.
Evolution – gradual continuous adaptation of living things to constant changes in environmental conditions.
Evolution is a process of historical development organic world.
In the Middle Ages, with the establishment of the Christian Church in Europe, the official point of view, based on biblical texts, spread: all living things were created by God and remain unchanged. He created them in pairs, so they live initially purposefully. That is, they were created for a purpose. Cats are made to catch mice, and mice are made to be eaten by cats. Despite the dominance of views on the immutability of species, interest in biology increased already in the 17th century. The ideas of evolution begin to be traced in the works of G.V. Leibniz. The development of evolutionary views arose in the 18th century, which were developed by J. Buffon and D. Diderot. Next, doubts arise about the immutability of species, which lead to the emergence of the theorytransformism - proof of the natural transformation of living nature. Adherents are: M.V. Lomonosov, K.F. Wolf, E.J. Saint-Hilaire.
By the end of the 18th century. A huge amount of material has accumulated in biology, where you can see:
Even seemingly distant views internal structure show certain similarities.
Modern views differ from fossils that have lived on Earth for a long time.
The appearance, structure and productivity of agricultural plants and animals changes significantly with changes in their growing conditions.
The ideas of transformism were developed by J.B. Lamarck created the evolutionary concept of the development of nature. His evolutionary idea is carefully developed, supported by facts, and therefore becomes a theory. It is based on the idea of development, gradual and slow, from simple to complex, and on the role of the external environment in the transformation of organisms.
J.B. Lamarck (1744-1829) – creator of the first evolutionary doctrine, also, as you already know, he introduced the term “biology”. He published his views on the development of the organic world in the book “Philosophy of Zoology”.
1. In his opinion, evolution proceeds on the basis of the internal desire of organisms for progress and perfection, which is the main driving force. This mechanism is inherent in every living organism.
2. The law of direct adaptation. Lamarck recognizes that the external environment influences living organisms. Lamarck believed that the reaction to changes in the external environment is an adaptive adaptive response to changes in the external environment (temperature, moisture, light, nutrition). He, like all his contemporaries, believed that changes arising under the influence of the environment can be inherited. As an example, we give the Arrow leaf plant. The arrowhead leaf forms a ribbon-shaped leaf in water, a floating rounded leaf on the surface of the water, and an arrow-shaped leaf in the air.
3. “The law of exercise and non-exercise of organs.” Lamarck represented the emergence of new characteristics in evolution as follows: a change in conditions is immediately followed by a change in habits. As a result, organisms develop good habits and they begin to exercise some organs that they have not used before. He believed that intense exercise of organs leads to their enlargement, and lack of exercise leads to degeneration. On this basis, Lamarck formulates the law of exercise and non-exercise. For example, the long legs and neck of a giraffe are a hereditary change associated with the constant use of these parts of the body when obtaining food. Thus, shore birds (heron, crane, stork), which swim reluctantly but are forced to live near water in search of food, are constantly in danger of plunging into silt. To avoid this, they make every effort to stretch and lengthen their legs as much as possible. The constant exercise of organs by force of habit, directed by the will of the animal, leads to its evolution. In a similar way, in his opinion, all special adaptations in animals develop: the appearance of horns in animals, the elongation of the anteater’s tongue.
4. “The law of inheritance of acquired characteristics.” According to this "law" useful changes are passed on to offspring. But most examples from the life of living organisms cannot be explained from the perspective of Lamarck’s theory.
Conclusion: Thus, J.B. Lamarck was the first to propose a detailed concept of transformism - the variability of species.
Lamarck's evolutionary doctrine was not sufficiently conclusive and did not receive wide recognition among his contemporaries.
The greatest evolutionary scientist is Charles Robert Darwin (1809-1882).
3. Report – information about Charles Darwin
In the first half of the 19th century. England became the most advanced capitalist country, with high level development of industry and agriculture. Livestock breeders have achieved exceptional success in developing new breeds of sheep, pigs, cattle, horses, dogs, and chickens. Plant growers have obtained new varieties of grain, vegetable, ornamental, berry and fruit crops. These advances clearly showed that animals and plants change under human influence.
Great geographical discoveries that enriched the world with information about new species of plants and animals, special people from overseas countries.
The sciences are developing: astronomy, geology, chemistry, botany and zoology have been significantly enriched with knowledge about the species of plants and animals.
Darwin was born at such a historical moment.
Charles Darwin was born on February 12, 1809 in the English city of Shrewsbury in the family of a doctor. From an early age, he developed an interest in communicating with nature, in observing plants and animals in their natural habitat. Deep observation, passion for collecting and systematizing material, the ability to make comparisons and broad generalizations, and philosophical thinking were natural qualities of Charles Darwin’s personality. After graduating from school, he studied at the Universities of Edinburgh and Cambridge. During that period, he met famous scientists: geologist A. Sedgwick and botanist J. Hensloe, who contributed to the development of his natural abilities and introduced him to the methods of field research.
Darwin was with the evolutionary ideas of Lamarck, Erasmus Darwin and other evolutionists, but he did not find them convincing.
The turning point in Darwin's biography was his voyage (1831-1836) as a naturalist on the Beagle. During the trip, he collected a large amount of factual material, the generalization of which led to conclusions that led to preparations for a sharp revolution in his worldview. Darwin returns to England a convinced evolutionist.
Upon returning to his homeland, Darwin settled in the village, where he spent his entire life. For 20 years. A long period of development of a coherent theory of evolution begins, based on the dissectionmechanism of the evolutionary process .
Finally 1859 Darwin's book "The Origin of Species by Means of Natural Selection" was published.
Its edition (1250 copies) was sold out in one day - an amazing occurrence in the book trade of that time.
In 1871 The third fundamental work, “The Descent of Man and Sexual Selection,” was published, which completed the trilogy of Darwin’s main works on the theory of evolution.
Darwin's entire life was devoted to science and was crowned with achievements that were included in the fund of the largest generalizations of natural science.
The great scientist died on April 19, 1882, and was buried next to Newton’s grave.
CONTINUED TEACHER
Darwin's discovery of the theory of evolution took society by surprise. One of his friends, greatly offended by the fact that he was equated with monkeys, sent him a message: “Your former friend, now a descendant of a monkey.”
In his works, Darwin showed that the species that exist today evolved naturally from other, more ancient species.
Purposefulness - observed in living nature, is the result of natural selection of traits useful for the body.
BASIC PROVISIONS OF THE THEORY OF EVOLUTION
All types living beingswere never created by anyone
Types of origin , naturallygradually transformed and improved
At the heart of the transformation speciesare variability, heredity, natural selection
The result of evolution is the adaptability of organisms to living conditions (environment) and the diversity of species in nature.
4. FIXING :
Working on task cards and checking them.
I appoint one responsible student in each row who distributes task cards. Students complete assignments. The person in charge collects and checks the answers and assigns grades. Which we will discuss in the next lesson.
Conclusion :
The driving forces (factors) of evolution (according to Darwin) are the struggle for existence and natural selection based on hereditary variability.
Charles Darwin created a theory of evolution that was capable of answering the most important questions: about the factors of the evolutionary process and the reasons for the adaptability of living beings to the conditions of existence. Darwin managed to see the victory of his theory; His popularity during his lifetime was enormous.
Testing for the lesson: Evolutionary teaching.
1. The result of evolution was:
A – artificial and natural selection;
B – hereditary variability;
B – adaptability of organisms to their environment;
D – diversity of species.
2. Who created the holistic theory of evolution:
A – Roulier;
B – Lamarck;
B – Darwin
3. The main factor, the main driving force of the evolutionary process:
A – mutational variability;
B – struggle for existence;
B – natural selection;
G – modification variability.
4. Modern species of animals and plants were not created by God, they originated from the ancestors of animals and plants through evolution. Species are not eternal, they have changed and are changing. Which scientist managed to prove this?
A-Lamarck;
B- Darwin,
B-Linnaeus;
G-Timiryazev;
D-Roulier.
5. The driving and guiding force of evolution is:
A – divergence of characters;
B – diversity of environmental conditions;
B – adaptability to environmental conditions;
G – natural selection of hereditary changes.