Back forward

Attention! Slide previews are for informational purposes only and may not represent all the features of the presentation. If you are interested in this work, please download the full version.

Purpose of the lesson: To form in students a system of knowledge about different views on the origin of life on Earth.

Lesson objectives:

I. Educational:

1. Show the role of experiment in resolving scientific disputes about the origin of life.
2. To teach to analyze the main scientific hypotheses about the origin of life.

II. Educational:

1. Continue to develop the desire for independent cognitive activity.
2. Continue the formation of formal logical skills of explanation, specification, definition, generalization.

III. Educational:

1. Intellectual - to continue the formation of a scientific worldview.
2. Ecological – consolidation of knowledge about the relationship between living and inanimate nature.
3. Moral - the formation of knowledge and beliefs of students about human responsibility for preserving the integrity of the biosphere of our planet.

Motivation:

The origin of life on our planet is the subject of centuries-old discussions in which more than one generation of humanity has participated. This interesting area of ​​knowledge, which has scientific, philosophical and ideological significance, still attracts the attention of researchers from various directions.

The study of various theories about the origin of life on Earth is necessary to form a holistic idea of ​​the historical path of development of living nature and the formation of a scientific worldview.

Students should know:

1. Basic provisions of theories about the origin of life;
2. Modern ideas about the origin of life on Earth (theory of biochemical evolution).

Students should be able to:

1. Reveal the key provisions of the main theories about the origin of life on Earth;
2. Give a description of the experiments of F. Redi, L. Spallanzani, L. Pasteur, S. Miller, reveal their significance for resolving the question of the origin of life;
3. Reveal the main provisions of modern ideas about the origin of life on Earth (theories of biochemical evolution);
4. Formulate the main provisions of the theory of A.I. Oparin.

Lesson equipment:

• lesson plan;
• abstract;
• Handout;
• tasks for control;
• presentation;
• laptop;
• multimedia projector;
• screen.

Interdisciplinary connections:

a) physics (device design, physical phenomena);
b) chemistry (composition of the atmosphere, chemical substances);
c) history (development of science);
d) philosophy (formation of a scientific worldview);
e) foreign language (translation of terms).

Literature for teachers:

1. Sivoglazov V.I., Agafonov I.B. General biology 10-11. – M.: Bustard, 2005
2. Sivoglazov V.I., Sukhova T.S., Kozlova T.A. General biology. Teacher's manual. – M.: IRIS PRESS, 2004
3. Sukhova T.S. Biology lesson. Technology of developmental education. – M.: Ventana-Graf, 2001

Literature for students:

1. Sivoglazov V.I., Agafonov I.B. General biology 10-11.– M.: Bustard, 2005

Chronocard of the lesson:

1. Organizational moment

Greetings, checking those present against the list, wishes for successful work in class.

2. Control of the initial level of knowledge (standards of correct answers are indicated in brackets)

Goals:

• Determine the level of knowledge of students.
• Adjust the difficulty level of presenting new material.

1. By what main features (criteria) can you distinguish a living object from a nonliving one?

(Unity of the chemical composition of living organisms, metabolism, irritability, growth, reproduction, development, adaptability to the environment, self-regulation).

2. Where and when did the first living organisms arise? What were they like? (The first organisms appeared about 3 billion years ago in the aquatic environment; they were unicellular prokaryotes, fed on organic matter of the ocean, anaerobes.)

3. What stages in the development of plants on Earth can you name? (unicellular, multicellular; the emergence of photosynthesis, the sexual process; access to land, development of terrestrial vegetation.)

4. What stages in the development of animals on Earth can you name? (Single-celled, colonial, multicellular; the appearance of the sexual process; the appearance of invertebrates and vertebrates; access to land; complication in structure due to the terrestrial way of life.)

5. What substances are included in living organisms?

(Inorganic (water, mineral salts) and organic (amino acids, proteins, fats, carbohydrates, etc.))

3. Study of new material (an explanation of the new material is accompanied by a presentation; the slide numbers are indicated in the text)

3.1. Formulation of the problem

Life has existed on Earth for billions of years. It fills all corners of our planet.

From ancient times to our time, a huge number of hypotheses about the origin of life have been put forward. The specificity of living things determines a number of questions that need to be answered when solving the problem of the origin of life:

• How did life arise and develop on our planet?
• How did the cell, the structural unit of living things, arise?
• How did all the substances and structures specific to living things originate?
• How was the existing metabolism formed? Etc.

We have to get acquainted with the hypotheses of the origin of life, analyze them and form an idea of ​​how life arose and developed on Earth.

3.2. Development of ideas about the origin of life on Earth (slide No. 1)

Since time immemorial, the origin of life has been a mystery to mankind. From the moment of his appearance, thanks to work, a person begins to stand out among other living beings.

But the ability to ask yourself the question “where are we from?” people receive it relatively recently - 7-8 thousand years ago.

Until this time, man had difficulty separating himself from other animals (man was both a hunter and a kind of game), but gradually he began to separate himself from nature with his inner spiritual world. The first primitive forms of belief in unreal, supernatural or divine forces arose already 35-40 thousand years ago.

3.3. Basic theories of the origin of life on Earth (Slide No. 2)

• Creationism
(Slide No. 3)

According to this theory, life arose as a result of some supernatural event in the past, which most often means divine creation. The idea of ​​the creation of the world as a “creative act” of God arose, and this myth underlies all religions.

Spontaneous generation theory

Proponents of this theory argued that living organisms arose repeatedly from inanimate matter through spontaneous generation. – concept of abiogenesis (from the Greek “a” - not, “bios” - life, “genesis” - origin). (Slide No. 4) Ancient Greek philosophers accepted the idea of ​​the emergence of living beings from water or from various wet or rotting materials. But even Thales (624-547 BC) challenged mythological ideas and created a spontaneously materialistic worldview with elements of dialectics. According to Thales and his followers, the emergence of living beings from water occurred without any intervention of spiritual forces; life is a property of matter. According to Aristotle (384-322 BC), certain particles of matter contain an “active principle” that can, under suitable conditions, create a living organism. This "beginning" can be found in a fertilized egg, rotting meat, mud and sunlight:

“These are the facts - living things can arise not only as a result of the mating of animals, but also the decomposition of the soil... Some plants develop from seeds, while others spontaneously arise under the influence of the forces of nature from decaying earth or certain parts of plants...”

However, with the advent of Christianity, especially in the Middle Ages, the theory of spontaneous generation came under the yoke of the Church. She was considered an attribute of witchcraft and a manifestation of the devil. Nevertheless, she continued to exist.

At the turn of the XVI-XVII centuries. Van Helmont (1579 - 1644) described an experiment in which he managed to obtain mice from dirty linen and wheat placed in a dark closet. Van Helmont considered human sweat to be the active source of mouse development. (Slide No. 5)- To biogenesis concept (from the Greek “bios” - life, “genesis” - origin). (Slide No. 6)

In 1668 the Italian physician Francesco Redi (1626-1698) proved that the white worms found in meat are fly larvae; If meat or fish are covered while they are fresh, and the access of flies is prevented, then, although they will rot, they will not produce worms. From this F. Redi concluded that living things originate only from living things). (Slide No. 7) In 1765, Lazzardo Spallanzani (1729-1799) boiled meat and vegetable concoctions and immediately sealed them. A few days later he examined the decoctions and found no signs of life. From this he concluded that the high temperature destroyed all living things, and nothing new could arise. (Slide No. 8)

J. Needham - supporter vitalism (from the Latin vita - life), explained the negative results obtained by L. Spallanzani by the fact that he subjected his infusions to too harsh processing, as a result of which their “vital force” was destroyed. (Slide No. 9) According to vitalists, “life force” is present everywhere. It is enough just to “breathe” it, and the inanimate will become alive.

In 1862, the great French scientist Louis Pasteur (1822-1895) published his observations on the problem of arbitrary spontaneous generation. He proves that the sudden appearance (“spontaneous spontaneous generation”) of microbes in various types of putrid tinctures or extracts is not the emergence of life. Rotting and fermentation are the result of the vital activity of microorganisms introduced from the outside. His research finally destroyed age-old prejudices about spontaneous generation.

Fig.1. L. Pasteur's experiment in flasks with S-shaped necks:

1 - flask with sugared yeast water; after sterilization and cooling remains sterile for a long time;

2 - the same flask 48 hours after removing the curved neck; growth of microorganisms is observed. (slides No. 10,11)

• Steady State Theory
(Slide No. 12)

According to this theory, the Earth existed forever, never came into existence, was always capable of supporting life, and any changes on it were completely insignificant. This theory currently does not stand up to criticism.

• Panspermia theory
(Slide No. 13)

In the 5th century BC. Greek philosopher Anaxagoras expressed the idea of ​​cosmic sowing - panspermia(from the Greek “pan” - all and “sperma” - seed). According to his teaching, life arose from a seed that exists “always and everywhere.” According to this theory, the embryos of life were brought to Earth by meteorites or cosmic dust. This theory does not propose any mechanism for the emergence of life, simply putting forward a postulate about its extraterrestrial origin. It is argued that life could arise repeatedly at different times and in different places in the Universe.

4. Modern ideas about the origin of life

(Slide 14)

The modern theory of the origin of life is based on the idea that biological molecules may have arisen in the distant geological past through inorganic means.

Most widespread in the twentieth century. received the theory of biochemical evolution, proposed independently of each other by the Russian chemist A.I. Oparin (1894 - 1980) and the English biologist D. Haldane (1892 - 1964).

• Theory of biochemical evolution
(Slide No. 15)

Stage 1 – abiogenic emergence of organic monomers Our planet arose about 4.6 billion years ago. The gradual densification of the planet was accompanied by the release of a huge amount of heat, radioactive compounds decayed, and a stream of hard ultraviolet radiation came from the Sun. After 500 million years, the slow cooling of the Earth began. The formation of the earth's crust was accompanied by active volcanic activity. It is believed that the primordial atmosphere consisted primarily of ammonia, water, methane, carbon monoxide and carbon dioxide. The absence of oxygen gave it restorative properties. On May 3, 1924, at a meeting of the Russian Botanical Society, the young scientist A.I. Oparin expressed the opinion that in the conditions of the primary atmosphere of the Earth, significantly different from the current one, the synthesis of all precursor substances necessary for the origin of life could have occurred.

Under such conditions, organic substances could be created much more easily and could be preserved without undergoing decay for a long time. A.I. Oparin believed that complex substances could be synthesized from simpler ones in ocean conditions. The energy required for reactions was brought by solar radiation, because the protective ozone shield did not yet exist; synthesis also took place under conditions of lightning discharges.

Conditions on primitive Earth (slides No. 16,17):

The diversity of simple compounds found in the ocean and the large time scales suggest the possibility of accumulation in the ocean of a large amount of organic matter, which formed the “primary broth” in which life could have originated.

Scheme of formation of the “primary broth”

This theory was confirmed in the experiments of S. Miller conducted in 1953. (Slide 18)

Fig.2. Diagram of S. Miller's device:

1 - reaction flask; 2 - tungsten electrodes; 3 - spark discharge; 4 - flask with boiling water; 5 - fridge; 6 - trap; 7 - valve through which the gas mixture is supplied to the apparatus

He passed electric discharges through a gas mixture containing methane, ammonia, molecular hydrogen and water vapor, i.e., simulating the atmospheric composition of the primitive Earth, and then analyzed the resulting reaction products. Tungsten electrodes were installed in the reaction flask containing a mixture of gases. Spark discharges with a voltage of 60,000 V were passed for a week. In another flask (small), water was maintained at a boil. Water vapor passed through the reaction flask and condensed in the refrigerator. During the circulation process, they captured reaction products from the reaction flask and transferred them to a trap, where they were concentrated. When identifying the reaction products, organic compounds were discovered: urea, lactic acid and some amino acids.

Stage 2 – formation of biological polymers and coacervates (Slide No. 19)

A.I. Oparin believed that the decisive role in the transformation of non-living things into living things belongs to proteins. Protein molecules formed complexes with the surrounding water molecules. The fusion of such complexes with each other led to their separation from the aquatic environment, forming coacervates(from Latin “coacervus” - clot). Coacervate droplets were capable of: exchanging substances with the environment and accumulating various compounds. The absorption of metal ions by coacervates led to the formation of enzymes. Proteins in coacervates protected nucleic acids from the damaging effects of ultraviolet radiation. In the drops themselves, further chemical transformations of the substances that got there took place. At the interface of the droplets with the external environment, lipid molecules lined up, forming a primitive membrane that increased the stability of the entire system.

Stage 3 – formation of membrane structures and primary organisms (probionts) Around the coacervates, rich in organic compounds, layers of lipids appeared, separating the coacervate from the surrounding aquatic environment. Lipids were transformed during evolution into the outer membrane, which significantly increased the viability and stability of organisms. This is how probionts arose - primitive heterotrophic organisms that fed on the organic substances of the primordial broth. This happened 3.5 - 3.8 billion years ago. Chemical evolution has ended.

The essence of the theory of A.I. Oparin can be formulated in the form of three postulates:

1. Life is one of the stages of the evolution of the Universe. 2. The emergence of life is a natural result of the chemical evolution of carbon compounds. 3. For the transition from chemical evolution to biological evolution, the formation and natural selection of integral multimolecular systems isolated from the environment, but constantly interacting with it, which were called probionts, are necessary.

Conclusions. (Slide No. 20)

The centuries-old history of mankind knows many hypotheses about the origin of life on Earth. Since ancient times, there have been two completely opposite points of view on this issue. One of them claims that living things arise from non-living things - this is abiogenesis. The second is of the opinion that living things can only arise from living things - this is biogenesis. Let’s try to understand in this article what is the difference between the theories of biogenesis and abiogenesis.

History of views

Ideas about clearly correlate with the level of knowledge of a particular era. In ancient times, when the level of knowledge was still small, theories of the origin of living things were striking in their fantastic nature. Let us present some views of philosophers and naturalists of the past. For example, Empedocles (5th century BC) believed that trees lay eggs. Aristotle (IV century BC) argued that lice come from meat, and bedbugs come from the juice of the body of animals. These views on the spontaneous generation of life as such existed until the middle of the 17th century, when the English philosopher F. Bacon (1561-1626) theoretically, and the Italian physician F. Redi (1626-1698) and Louis Pasteur (1822-1895) practically proved the impossibility of the spontaneous generation of life . It was then that these two opposing camps began to form, two mutually exclusive theories of the origin of life - biogenesis and abiogenesis.

A little theory

Under abiogenesis (from the Greek prefix of negation - a, bio- life and genesis- emergence) understand the theory of the emergence of organic structures from inorganic ones and outside a living organism. In a broad sense, abiogenesis is about the origin of living things from non-living things. And here it is necessary to clarify what is considered life and when the inanimate becomes alive. And since even today the definition of life is interpreted in different ways and from different points of view, there are still many supporters of both abiogenesis and biogenesis.

Life in the theory of abiogenesis

In this concept, the most important are the genetic and evolutionary criteria that determine life. All other criteria - thermodynamic and environmental - are considered secondary. The provisions of abiogenesis are as follows:

• Living and nonliving things differ in chemical composition and its characteristics (metabolism). All theories in this direction are called biochemical abiogenesis.
• The origin of life occurred on Earth, naturally and with the expenditure of free energy. This is the result of the emergence of complex organic substances from simple inorganic ones with the emergence of new chemical reactions between them. All theories of the origin of life in this direction are called geocentric.
• The main properties and characteristics of living things are metabolism, self-reproduction of their own kind, heredity and variability.

Thus, abiogenesis is a geocentric and chemical theory that explains the origin of living things.

Life as a result of biogenesis

Biogenesis focuses on the thermodynamic and ecological properties that distinguish living from nonliving. In this case, genetic, evolutionary and biochemical approaches are considered complementary. The concepts of biogenesis are as follows:

• Living, like non-living, are two interconnected and inseparable states of matter. These theories are called physical theories.
• The thermodynamic (resistance to entropy) and systemic (subordination and stable dynamic connections) component are the main properties and signs of life.
• Life arose in the Universe, and the Earth's biosphere is a manifestation of the living part of the Cosmos. These theories are called cosmic.

Biogenesis, then, is a cosmocentric physical theory of the origin of life.

Modern views

Modern science adheres to a point of view that combines all concepts into a single system of knowledge about how inanimate matter turned into living matter. As the most probable path of origin of living things, modern science recognizes that the initial stage is abiogenesis. And it consists of 3 initial stages:

• The appearance of biological monomers.
• Formation of biological polymers.
• The appearance of membrane structures and primary protozoan organisms - protobionts.

Non-biological formation of organic matter

Or prebiological abiogenesis is the emergence of organic substances from inorganic ones. In 1924, Russian academician A.I. Oparin (1894-1980) suggested that in solutions saturated with high-molecular compounds, zones of increased concentrations (coacervates or coacervate drops) spontaneously form, which are isolated from the environment, but maintain exchange with it. in 1929, the English scientist John Haldane (1892-1964) supported it, and the theory of coacervates, which assumes the spontaneous generation of organic substances in the early stages of the development of our planet with unique physical conditions, became firmly established in science.

Evidence for the abiogenesis hypothesis

At first, it was not possible to prove the possibility of spontaneous synthesis of organic substances from inorganic ones. However, today certain stages have already been completed and results have been obtained.

It all started in 1953, when chemists Stanley Miller and Harold K. Urey conducted an experiment with the primordial broth (an environment similar to prebiotic on Earth). The influx of energy (up to 60 thousand V) under pressure and at a temperature of 80 degrees Celsius led to the formation of fatty acids, urea and several amino acids (protein monomers). And already in 2008, American biologists created a “protocell” with a membrane; in 2011, Japanese biologists published work on creating a vesicle with a membrane and the ability to divide.

Precarious positions

Despite the successes of biologists in experimental attempts to confirm the Oparin-Haldane theory about the origin of life on the planet in coacervates, all the resulting structures are still far from the structure of a living cell. does not recognize these experiments as indisputable evidence of precisely this origin of life. Both biogenesis and abiogenesis are theories that have not yet been confirmed experimentally. Considering that the path from inorganic molecules to a living cell was long, with many forks and stops, scientists can only hypothesize how this path could have been passed. But all these hypotheses do not prove that this is exactly what happened on Earth many billions of years ago.

The probability is absolutely incredible

The randomness of the emergence of a living cell in the primordial broth has been calculated mathematically. British mathematician Fred Hall, using modern computers, calculated the probability of the random formation of an amoeba protein. And this probability turned out to be negligible - 1/10*40000. Recall that this is under some ideal conditions. And this leads to certain thoughts and provides arguments for supporters of other theories and concepts of the origin of life on our planet.

The incredible is probable

But, as you know, everything is relative. On our planet and in our world - here are a few examples that will make you wonder whether such an accident as the emergence of life in the primordial soup is really so impossible.

• If human life expectancy were 100,000 years, then we would be guaranteed (that is, 100%) to die in plane crashes.
• The probability of winning the Cool Million lottery is 1 in 5,200,000. Nevertheless, American Valerie Wilson won the main prize twice: in 2002 and in 2006.
• In 2009, in the Bulgarian lottery “6 out of 41”, the same numbers were drawn in two draws with a difference of 4 days (4 15 23 24 35 42). The probability of such an event is 3.61. 10−14.

For people who want to constantly improve, learn something and constantly learn something new, we specially made this category. It contains exclusively educational, useful content that you will certainly enjoy. A large number of videos can perhaps rival even the education we are given at school, college or university. The biggest thing about training videos is that they try to give the latest, most relevant information. The world around us in the era of technology is constantly changing, and printed educational publications simply do not have time to provide the latest information.

Among the videos you can also find educational videos for preschool children. There your child will be taught letters, numbers, counting, reading, etc. Agree, it’s a very good alternative to cartoons. For primary school students you can also find English language training and help in studying school subjects. For older students, educational videos have been created that will help you prepare for tests, exams, or simply deepen your knowledge in a particular subject. The acquired knowledge can have a qualitative impact on their mental potential, as well as please you with excellent grades.

For young people who have already graduated from school, are studying or not studying at university, there are many fascinating educational videos. They can help them deepen their knowledge of the profession for which they are studying. Or get a profession, such as a programmer, web designer, SEO optimizer, etc. This profession is not yet taught at universities, so you can become a specialist in this advanced and relevant field only by self-education, which we are trying to help with by collecting the most useful videos.

For adults, this topic is also relevant, since it often happens that after working in a profession for years, you come to the understanding that this is not your thing and you want to learn something more suitable for yourself and at the same time profitable. Also among this category of people, there are often videos on the type of self-improvement, saving time and money, optimizing their lives, in which they find ways to live a much better and happier life. Even for adults, the topic of creating and developing your own business is very suitable.

Also among the educational videos there are videos with a general focus that are suitable for almost any age; in them you can learn about how life began, what theories of evolution exist, facts from history, etc. They perfectly broaden a person’s horizons, making him a much more erudite and pleasant intellectual interlocutor. Such educational videos are indeed useful for everyone to watch, without exception, since knowledge is power. We wish you a pleasant and useful viewing!

Nowadays, it is simply necessary to be what is called “on the wave”. This refers not only to news, but also to the development of one’s own mind. If you want to develop, explore the world, be in demand in society and be interesting, then this section is just for you.

Water, constantly evaporating from the surface of the Earth, condensed in the upper layers of the atmosphere and again fell in the form of rain on the hot earth's surface. The gradual decrease in temperature led to downpours, accompanied by continuous thunderstorms, hitting the Earth. Reservoirs began to form on the earth's surface.

Atmospheric gases and those substances that were washed out of the earth's crust dissolved in hot water. In the atmosphere, the simplest organic substances (formaldehyde, glycerin, amino acids, urea, lactic acid) were formed from its components under the influence of frequent and strong electrical lightning discharges, powerful ultraviolet radiation coming from the Sun, and active volcanic activity, which was accompanied by emissions of radioactive compounds.

Since there was no free oxygen in the atmosphere yet, these compounds, entering the waters of the ancient ocean, were not oxidized and could accumulate, becoming more complex in structure and forming a concentrated "primordial broth" - a term introduced by . Organic substances, accumulating over millions of years in the water of the ancient ocean, formed a concentrated solution, or “primary broth.”

Formation of biological polymers and coacervates

The first stage of biochemical evolution was confirmed by numerous experiments, but what happened at the next stage, scientists can only guess, based on knowledge of chemistry and molecular biology.

Apparently, the simplest organic substances formed interacted with each other and with inorganic compounds entering water bodies. Fatty acids, reacting with alcohols, formed lipids, which formed fatty films on the surface of reservoirs. Amino acids combine with each other to form peptides. An important event of this stage was the appearance of nucleic acids - molecules capable of reduplication.

Modern biochemists believe that short RNA chains were the first to form, which could be synthesized independently, without the participation of special enzymes. The formation of nucleic acids and their interaction with proteins has become a necessary prerequisite for the emergence of life, which is based on matrix synthesis reactions and metabolism.

In the 20-30s of the XX century. science has returned to the idea of ​​spontaneous generation, taking into account the criticism that the concept of abiogenesis was subjected to in the 19th century. The spontaneous origin of life is impossible under modern conditions, but it could have happened in a long time ago, when conditions on Earth were different. At the beginning of the 20th century. the prevailing belief was that the organic substances underlying life (proteins, fats, carbohydrates) under natural conditions can only arise biogenically, i.e. through their synthesis by the organisms themselves. In the twenties A.I. Oparin and J. Haldane experimentally showed that in solutions of high-molecular organic compounds, zones of increased concentration can appear - coacervate drops - which in some sense behave like living objects: they spontaneously grow, divide and exchange matter with the surrounding liquid through a compacted interface.

Soviet biochemist A.I. Oparin (1894-1980) suggested that with powerful electrical discharges in the Earth’s atmosphere, which 4-4.5 billion years ago consisted of ammonia, methane, carbon dioxide and water vapor, the simplest organic compounds necessary for the emergence of life could arise . Prediction by A.I. Oparin has received wide recognition and has been confirmed by experiments. Particularly famous are the experiments of G. Ury and S. Miller (1955), conducted at the University of Chicago. By passing electrical discharges with voltages up to 60,000 V through a mixture of carbon dioxide, methane, ammonia, hydrogen and water vapor under pressure of several pascals at a temperature of +80 * C, they obtained the simplest fatty acids, urea, acetic and formic acids and several amino acids, in including glycine and alanine. The diagram of Miller's device is shown in Fig. 49 As is known, amino acids are the “building blocks” from which protein molecules are built. After some time, S. Fox managed to connect the latter into short irregular chains - template-free synthesis of polypeptides; similar polypeptide chains were later actually found, among other simple organic matter, in meteorite matter. Experimental evidence of the possibility of the formation of amino acids from inorganic compounds gave grounds to assume that the first step towards the emergence of life on Earth was the abiogenic synthesis of organic substances (Fig. 39).

Currently, abiogenic synthesis of many biologically important monomers has been carried out in various laboratories. Much information has been obtained regarding the abiogenic synthesis of amino acids (Table 14). The amino acids listed in the table are formed in gas or water mixtures of simple composition as a result of exposure to different energy sources. With some complication of the reaction mixture by introducing into it C2-, C3-hydrocarbons, acetaldehyde, hydroxylamine, hydrazine and other compounds, the formation of which easily occurs under the conditions of the primitive Earth, a significantly larger number of amino acids are synthesized, including those that have not been discovered as reaction products in gaseous and aqueous mixtures of simple composition. It has been experimentally proven that almost all the amino acids that make up natural proteins can be obtained in the laboratory by simulating the conditions of the primitive Earth.

An important step on the path of chemical evolution is the synthesis of nucleosides and nucleotides, and primarily adenine ones. The American biochemist K. Ponnamperuma was able to show that when UV irradiation of a mixture of aqueous solutions of adenine and ribose at a temperature of 40 degrees Celsius in the presence of phosphoric acid, a condensation reaction occurs, leading to the formation of adenosine. If the reaction is carried out by adding ethyl metaphosphate to the reaction mixture, the formation of nucleotides also takes place: AMP, ADP, ATP. The function of phosphorus compounds in these chemical syntheses is twofold: they play a catalytic role and can be directly included in the reaction products. The abiogenic synthesis of ATP, which is the result of several relatively simple chemical reactions, suggests the possible early appearance of this compound. The first living structures could obtain ATP from the environment.

The next stage of prebiological evolution is the further complication of organic compounds associated with the polymerization of monomers. All living cells are composed of four main types of macromolecules: proteins, nucleic acids, lipids and polysaccharides. Of these, proteins and nucleic acids are the most complex substances of the cell.

S. Fox carried out the abiogenic synthesis of polypeptides consisting of 18 natural amino acids with a molecular weight of 3000 to 10000 Da. A feature of the primary structure of these polymers was the specific sequence of amino acid residues found in them in the chain, which was probably due to the structural features of the amino acids themselves. The resulting polymers had many properties that brought them closer to natural proteins: they served as a source of nutrition for microorganisms, were hydrolyzed by proteinases, produced a mixture of amino acids upon acid hydrolysis, had catalytic activity and the ability to form microsystems delimited from the environment by membrane-like surface layers. Due to their great similarity to natural proteins, the polypeptides synthesized by S. Fox were called