In 1924, the Russian scientist Alexander Ivanovich Oparin first formulated the basic principles of the concept of prebiological evolution. He viewed the emergence of life as a single natural process, which consisted of the initial chemical evolution that took place under the conditions of the early Earth, which gradually moved to a qualitatively new level - biochemical evolution.

The essence of the hypothesis was as follows: the origin of life on Earth is a long evolutionary process of the formation of living matter in the depths of nonliving matter. And this happened through chemical evolution, as a result of which the simplest organic substances were formed from inorganic ones under the influence of strong physicochemical factors.

Considering the problem of the origin of life through biochemical evolution, Oparin identifies three stages of the transition from inanimate to living matter: 1st stage of the synthesis of initial organic compounds from inorganic substances in the conditions of the primary atmosphere of the early Earth; Stage 2 of the formation of biopolymers, lipids, hydrocarbons from accumulated organic compounds in the primary reservoirs of the Earth;

Stage 3 - self-organization of complex organic compounds, the emergence on their basis and evolutionary improvement of metabolic processes and reproduction of organic structures, culminating in the formation of the simplest cell.

At the first stage, about 4 billion years ago, when the Earth was lifeless, abiotic synthesis of carbon compounds and their subsequent prebiological evolution took place on it. This period of the Earth's evolution was characterized by numerous volcanic eruptions with the release of huge amounts of hot lava. As the planet cooled, water vapor in the atmosphere condensed and rained down on the Earth, forming huge expanses of water.

Since the surface of the Earth still remained hot, the water evaporated, and then, cooling in the upper layers of the atmosphere, fell again onto the surface of the planet. These processes continued for many millions of years. Thus, various salts were dissolved in the waters of the primary ocean. In addition, it also contained organic compounds: sugars, amino acids, nitrogenous bases, organic acids, etc., which were continuously formed in the atmosphere under the influence of ultraviolet radiation, high temperature and active volcanic activity.

The primordial ocean probably contained in dissolved form various organic and inorganic molecules that entered it from the atmosphere and surface layers of the Earth. The concentration of organic compounds constantly increased, and, in the end, the ocean waters became a “broth” of protein-like substances - peptides.

At the second stage, as conditions on Earth softened, under the influence of electrical discharges, thermal energy and ultraviolet rays on the chemical mixtures of the primary ocean, it became possible for the formation of complex organic compounds - biopolymers and nucleotides, which, gradually combining and becoming more complex, turned into protobionts (precellular ancestors living organisms). The result of the evolution of complex organic substances was the appearance of coacervates, or coacervate drops.

Coacervates are complexes of colloidal particles, the solution of which is divided into two layers: a layer rich in colloidal particles and a liquid almost free of them. Coacervates had the ability to absorb various substances dissolved in the waters of the primary ocean. As a result, the internal structure of the coacervates changed, which led either to their disintegration or to the accumulation of substances, that is, to growth and changes in the chemical composition, increasing their stability in constantly changing conditions.

The theory of biochemical evolution considers coacervates as prebiological systems, which are groups of molecules surrounded by a water shell. Coacervates turned out to be able to absorb various organic substances from the external environment, which provided the possibility of primary metabolism with the environment.

At the third stage, as Oparin assumed, natural selection began to act. In the mass of coacervate droplets, the selection of coacervates that were most resistant to given environmental conditions occurred. The selection process took place over many millions of years, resulting in only a small fraction of coacervates being preserved. However, the preserved coacervate droplets had the ability to undergo primary metabolism. And metabolism is the primary property of life.

At the same time, having reached a certain size, the mother drop could break up into daughter drops, which retained the features of the mother structure. Thus, we can talk about the acquisition by coacervates of the property of self-reproduction - one of the most important signs of life. In fact, at this stage, coacervates turned into the simplest living organisms.

Further evolution of these prebiological structures was possible only with the complication of metabolic and energy processes inside the coacervate. Only a membrane could provide stronger isolation of the internal environment from external influences. Around the coacervates, rich in organic compounds, layers of lipids appeared, separating the coacervate from the surrounding aqueous environment. During the process of evolution, lipids were transformed into the outer membrane, which significantly increased the viability and stability of organisms.

In protocells like cacervates or microspheres, nucleotide polymerization reactions took place until a protogen was formed from them - a primary gene capable of catalyzing the emergence of a certain amino acid sequence - the first protein. Probably the first such protein was a precursor to an enzyme that catalyzes the synthesis of DNA or RNA.

Those protocells in which the primitive mechanism of heredity and protein synthesis arose divided faster and took into themselves all the organic substances of the primary ocean. At this stage, natural selection was already underway for the speed of reproduction; any improvement in biosynthesis was picked up, and new protocells replaced all previous ones.

The theory of A.I. Oparin was warmly supported by Cambridge professor John Haldane. He opened the debate on the origin of life in an article published in the Rationalist Annual in 1929. In it, D. Haldane put forward the hypothesis that huge amounts of organic compounds accumulated on the primitive Earth, forming what he called hot dilute soup (later the name primeval soup or proto-broth took root).

Charles Darwin believed that inanimate matter could be transformed into living matter with the help of electricity - after all, his grandfather, Erasmus Darwin, was greatly impressed by Frankenstein, written by Mary Shelley. The idea that pyrotechnic exercises with electricity could give rise to life had enormous appeal; so it is not surprising that there was great interest in Stanley Miller's experiment, the results of which were published in 1953.

Miller's experiment, which became a turning point in this field, was extremely simple. The apparatus consisted of two glass flasks connected in a closed circuit. A device that simulates lightning effects is placed in one of the flasks - two electrodes, between which a discharge occurs at a voltage of about 60 thousand volts; In another flask, water is constantly boiling. The apparatus is then filled with the atmosphere believed to have existed on ancient Earth: methane, hydrogen and ammonia.

The apparatus worked for a week, after which the reaction products were examined. Basically it turned out to be a viscous mess of random compounds; a certain amount of organic substances was also found in the solution, including the simplest amino acids - glycine (NH 2 COOH) and alanine (NH 2 CH(CH 3) COOH).

The publication of data from Miller's experiment aroused unprecedented interest, and soon many other scientists began to repeat this experiment. It was discovered that modifying the experimental conditions makes it possible to obtain small amounts of other amino acids. However, repeating the experiment was difficult, and many results were obtained only after many unsuccessful attempts. It was reported that during the process of experiments, the basic components necessary for life arose.

The theory of spontaneous generation of life - chemical evolution - occupies a central place in modern scientific philosophy. According to this theory, life arises spontaneously from nonliving matter. One of its main propagandists was the biochemist Alexander Oparin (1894-1980). He outlined his ideas in the book The Origin of Life, published in Soviet

Union in 1924 and translated into English in 1938.

1. The primitive Earth had an essentially oxygen-free atmosphere.

2. When various natural sources of energy began to act on this atmosphere - for example, thunderstorms and volcanic eruptions - the basic chemical compounds necessary for organic life began to spontaneously form.

3. Over time, organic molecules accumulated in the oceans until they reached the consistency of a hot, dilute soup. However, in some areas the concentration of molecules necessary for the origin of life was particularly high, and nucleic acids and proteins were formed there.

4. Some of these molecules turned out to be capable of self-reproduction.

5. The interaction between the resulting nucleic acids and proteins eventually led to the emergence of the genetic code.

6. Subsequently, these molecules united, and the first living cell appeared.

7. The first cells were heterotrophs; they could not reproduce their components on their own and received them from the broth. But over time, many compounds began to disappear from the broth, and the cells were forced to reproduce them on their own. So the cells developed their own metabolism for independent reproduction.

In 1953, at the installation of biologist Stanley Miller

experiments were carried out, as a result of which primary cells or coacervates were obtained

Viscous, gel-like drop. Coacervates are capable of absorbing various organic substances from the external environment.

In 1929, the English biologist J. Haldane put forward the hypothesis of the origin of life from nonliving elements. The theory of biochemical

evolution is sometimes called a theory

Oparina - Haldane.

A.I. Oparin gave primacy in the formation of life to proteins, and J. Haldane - to nucleic acids.

The Oparin-Haldane hypothesis states that life on Earth arose abiogenically

Biochemical

Oparin believed that the transition from chemical evolution to biological evolution required the obligatory emergence of individual phase-separated systems capable of interacting with the surrounding external environment.

summary of other presentations

"The Biochemical Evolution Hypothesis" - Miller, Stanley Lloyd. The process that led to the emergence of life on Earth. Miller-Urey experiment. Primary broth. Coacervate drops. Hypothesis of A.I. Oparin. Origin of life on Earth. Conditions for the origin of life. Oparin-Haldane theory. Various aspects.

“Oparin hypothesis” - Living cell. Biography of A.I. Oparin. The hypothesis of the origin of life on Earth by A.I. Oparin. Formation of the Earth's atmosphere. Alexander Ivanovich Oparin. English biologist. Stages of the emergence of life on Earth. Biography. Installation by Stanley Miller. The theory of the origin of life on Earth. The hypothesis of the spontaneous origin of life. Concept. Hypothesis of biochemical evolution. Clots called coacervate droplets.

“Theories of biogenesis and abiogenesis” - Proponents of the theory of panspermia. Democritus Worms. The earth never came into being. Theories of biogenesis and abiogenesis about the origin of living matter. Theory of spontaneous generation. Amino acids. Lack of living organisms. English biochemist and geneticist John Haldane. Stages of the emergence of life on Earth. Creationism. Theory of biochemical evolution. Creationists. Theory of spontaneous generation. Describe the biochemical stage of chemical evolution.

“Chemical evolution” - Life arose in conditions that are unsuitable for modern biota. Geochronology. The geological history of the Earth is inseparable from its biological evolution. Only a few hundred participate in the construction of a living one. The concept of self-organization in chemistry. Protostar - the Sun. Russian chemist A.P. Rudenko. About 8 million chemical compounds are known. Biochemical evolution hypothesis (Oparin-Haldane). Elements that form the solid shells of planets.

“Biochemical evolution of Oparin” - Biochemical evolution. 2) Formation of biopolymers, lipids, hydrocarbons from accumulated organic compounds in the primary reservoirs of the Earth. 1894-1980. Considering the problem of the origin of life through biochemical evolution, Oparin identifies three stages of transition from inanimate to living matter. Oparin's theory. The origin of life on Earth is a long evolutionary process of the formation of living matter in the depths of nonliving matter.

“Theory of biochemical evolution” - Concentration of substances in coacervate droplets. The third stage was characterized by separation. The transition to autotrophic nutrition was of great importance for evolution. Life was created by a supernatural being. American chemist S. Fox composed mixtures of amino acids. Processes as a result of which life could arise on Earth. A hypothesis that considers life as the result of long evolution. Simple molecules.

Slide 2

In 1924, the Russian scientist Alexander Ivanovich Oparin first formulated the basic principles

concepts of prebiological evolution. He viewed the emergence of life as a single natural process, which consisted of the initial chemical evolution that took place under the conditions of the early Earth, which gradually passed to a qualitatively new level of biochemical evolution.

Slide 3

The essence of the hypothesis was as follows: the origin of life on Earth was a long evolutionary

the process of formation of living matter in the depths of nonliving matter. And this happened through chemical evolution, as a result of which the simplest organic substances were formed from inorganic ones under the influence of strong physicochemical factors.

Slide 4

Considering the problem of the emergence of life through biochemical evolution, Oparin identifies three stages of transition from inanimate to living matter:

1) the stage of synthesis of initial organic compounds from inorganic substances under the conditions of the primary atmosphere of the early Earth

2) the stage of formation of biopolymers, lipids, hydrocarbons from accumulated organic compounds in the primary reservoirs of the Earth;

Slide 5

Slide 6

Slide 7

Slide 8

At the second stage, as conditions on Earth softened, under the influence of electrical discharges, thermal energy and ultraviolet rays on the chemical mixtures of the primary ocean, it became possible to form complex organic compounds of biopolymers and nucleotides, which, gradually combining and becoming more complex, turned into protobionts (precellular ancestors of living organisms). The result of the evolution of complex organic substances was the appearance of coacervates, or coacervate drops.

Slide 9

Coacervates are complexes of colloidal particles, the solution of which is divided into two layers: a layer,

rich in colloidal particles, and a liquid almost free of them. Coacervates had the ability to absorb various substances dissolved in the waters of the primary ocean. As a result, the internal structure of the coacervates changed, which led either to their disintegration or to the accumulation of substances.

Slide 10

The theory of biochemical evolution considers coacervates as prebiological systems,

representing groups of molecules surrounded by a water shell. Coacervates turned out to be able to absorb various organic substances from the external environment, which provided the possibility of primary metabolism with the environment.

Slide 11

1 of 44

Presentation - Biochemical evolution

Text of this presentation

Theory of abiogenesis (biochemical evolution). Model A. Oparin -J. Haldane. Experiments by S. Miller. Problems and contradictions of the theory

In 1923, the Soviet biochemist Alexei Oparin developed the theory of biochemical evolution.

A. I. Oparin, Russian biochemist, academician, published his first book on this problem of the origin of life through biochemical evolution back in 1924
March 2, 1894 – April 21, 1980

billions of years ago, during the formation of the planet, the first organic substances were hydrocarbons, which were formed in the ocean from simpler compounds.
The basis of this theory was the idea:

A. Oparin considered the emergence of life as a single natural process, which consisted of the initial chemical evolution that took place under the conditions of the early Earth, which gradually moved to a qualitatively new level - biochemical evolution.

The essence of the hypothesis:
The origin of life on Earth is a long evolutionary process of the formation of living matter in the depths of nonliving matter.
This happened through chemical evolution, as a result of which the simplest organic substances were formed from inorganic ones under the influence of strong physicochemical factors.

Oparin identifies three stages of transition from inanimate to living matter:
1) the stage of synthesis of initial organic compounds from inorganic substances under the conditions of the primary atmosphere of the early Earth; 2) the stage of formation of biopolymers, lipids, hydrocarbons from accumulated organic compounds in the primary reservoirs of the Earth; 3) the stage of self-organization of complex organic compounds, the emergence on their basis and evolutionary improvement of the processes of metabolism and reproduction of organic structures, culminating in the formation of the simplest cell.

First stage (about 4 billion years ago)
As the planet cooled, water vapor in the atmosphere condensed and rained down on the Earth, forming huge expanses of water.
As the Earth's surface remained hot, water evaporated and then, cooling in the upper atmosphere, fell back onto the planet's surface.
Thus, various salts and organic compounds were dissolved in the waters of the primary ocean
These processes continued for many millions of years

Second phase
Conditions on Earth are softening; under the influence of electrical discharges, thermal energy and ultraviolet rays on the chemical mixtures of the primary ocean, it has become possible to form complex organic compounds - biopolymers and nucleotides, which gradually combine and become more complex.
The result of the evolution of complex organic substances was the appearance of coacervates, or coacervate drops.

Coacervates are complexes of colloidal particles, the solution of which is divided into two layers:
layer rich in colloidal particles
liquid almost free of them
Coacervates turned out to be able to absorb various organic substances from the external environment, which provided the possibility of primary metabolism with the environment.

preserved coacervate drops had the ability to undergo primary metabolism
Third stage
Natural selection began to act
as a result, only a small part of the coacervates was preserved
Having reached a certain size, the mother drop could break up into daughter drops, which retained the features of the parent structure

Later, the theory of biochemical evolution was developed in the works of the English scientist John Haldane

J. Haldane, an English geneticist and biochemist, since 1929 developed ideas consonant with the ideas of A.I. Oparin.

Life was the result of long evolutionary carbon compounds. Substances similar in their chemical composition to proteins and other organic compounds that form the basis of living organisms arose on the basis of hydrocarbons.
John Haldane formulated a hypothesis

Subsequently, absorbing protein substances from the environment, the structure of the coacervates became more complex, and they became similar to primitive, but already living cells, and the chemical compounds of their internal composition allowed them to grow, mutate, metabolize and multiply.
Coacervate (from the Latin coacervātus - “gathered in a heap”) or “Primary broth” is a multimolecular complex, drops or layers with a higher concentration of diluted substance than in the rest of the solution of the same chemical composition.

The theory of biochemical evolution and the origin of life on Earth, expressed by Alexei Oparin, is recognized by many scientists, however, due to the large number of assumptions and assumptions, it raises some doubts.

Postulates that life arose on Earth precisely from inanimate matter, under conditions that existed on the planet billions of years ago. These conditions included the presence of energy sources, a certain temperature regime, water and other inorganic substances - precursors of organic compounds. The atmosphere then was oxygen-free (the source of oxygen today is plants, but then there were none).
"Oparin-Haldane hypothesis"

Stages of the development of life on Earth according to the Oparin-Haldane hypothesis
Time period Stages of the origin of life Events occurring on Earth
From 6.5 to 3.5 billion years ago 1 Formation of the primary atmosphere containing methane, ammonia, carbon dioxide, hydrogen, carbon monoxide and water vapor
2 Cooling of the planet (below the temperature of +100 °C on its surface); condensation of water vapor; formation of the primary ocean; dissolution of gases and minerals in its water; powerful thunderstorms Synthesis of simple organic compounds - amino acids, sugars, nitrogenous bases - as a result of the action of powerful electrical discharges (lightning) and ultraviolet radiation
3 Formation of the simplest proteins, nucleic acids, polysaccharides, fats; coacervates
From 3.5 to 3 billion years ago 4 Formation of protobionts capable of self-reproduction and regulated metabolism as a result of the emergence of membranes with selective permeability and interactions of nucleic acids and proteins
3 billion years ago 5 The emergence of organisms with a cellular structure (primary prokaryotes-bacteria)

Very convincing evidence of the possibility of implementing the 2nd and 3rd stages of life development was obtained as a result of numerous experiments on the artificial synthesis of biological monomers.

For the first time in 1953, S. Miller (USA) created a fairly simple installation in which he managed to synthesize a number of amino acids and other organic compounds from a mixture of gases and water vapor under the influence of ultraviolet irradiation and electrical discharges

A publication in the journal Science describes data that eluded scientists more than 50 years ago.
A young employee at the University of Chicago, Stanley Miller, conducts his famous experiments on the synthesis of biological molecules. 1953 //Archives of the Department of Chemistry of the University of California at San Diego

Then Nobel laureate Harold Urey, who received a prestigious prize for the discovery of heavy water and subsequently became interested in the problems of cosmochemistry,
inspired one of his students, Stanley Miller, with the theory of a prehistoric abiotic soup, from which, under the influence of external factors, the first organic molecules emerged.
April 29, 189 – January 5, 1981 (age 87)

In order to recreate reactions in the laboratory under conditions similar to those that prevailed on Earth billions of years ago, Miller developed an original chemical device.

The device consists of a large reaction flask containing vapors of methane, ammonia and hydrogen, into which hot water vapor is pumped from below. On top are tungsten electrodes that generate a spark discharge. By simulating the conditions of a thunderstorm in the vicinity of an active coastal volcano in this way, Miller hoped to obtain biological molecules through synthesis.
Boiling water (1) creates a stream of steam, which is amplified by the aspirator nozzle (inset), a spark jumping between two electrodes (2) starts a set of chemical transformations, the refrigerator (3) cools the stream of water vapor containing reaction products that settle in a trap ( 4).// Ned Shaw, Indiana University.

In his experiment, Miller used a gas mixture consisting of:
ammonia
methane
hydrogen
water vapor
According to Miller's assumption, it was this mixture that predominated in the Earth's primary atmosphere.

Since these gases could not react under natural conditions, Miller exposed them to electrical energy, simulating lightning discharges from which energy was supposed to be obtained in the early atmosphere
At a temperature of 100 ° C, the mixture was boiled for a week, systematically exposed to electrical discharges.
An analysis of chemosynthesis carried out at the end of the week showed that out of the twenty amino acids that form the basis of any protein, only three were formed

After the death of Stephen Miller, while sorting through his diaries and archives, relatives and colleagues discovered notes related to the works of the 50s, as well as several bottles with signatures.
The signatures indicated that the contents of the flasks were nothing more than synthesis products in Miller’s apparatus, preserved by the author in an inviolable form.

The experiments of Stanley Miller, who tried to replicate the origin of life on Earth in a test tube, were much more successful than Miller himself believed. Modern methods have made it possible to find not five, but all 22 amino acids in chemical vessels sealed by scientists many decades ago.

Over the next 20 years it was established:
The atmosphere in Miller's experience was fictitious
The Earth's early atmosphere was not made of methane and ammonia, but of nitrogen, carbon dioxide and water vapor, and Miller's experiment was nothing more than an outright lie.
In the experiments, to obtain amino acids, they took ready-made ammonia, and by itself, in an abiogenic way, it is formed only at high pressure and temperatures from an equimal mixture of hydrogen and nitrogen, in the presence of a catalyst

Miller used the “cold trap” mechanism in the experiment, that is, the resulting amino acids were immediately isolated from the external environment.
Without this mechanism, atmospheric conditions would immediately destroy these molecules.

Miller, using the “cold trap” method, himself crushed his own assertion about the possibility of the free formation of amino acids in the atmosphere.
As a result, all efforts showed that even under ideal laboratory conditions it is impossible to synthesize amino acids without a “cold trap” mechanism to prevent the breakdown of amino acids already under the influence of their own environment, so there can be no question of their accidental occurrence in nature.

Scientific problems of Miller's experiments
The resulting amino acids turned out to be “non-living”: they were in the wrong direction of rotation – the “chirality” effect. As a result of the experiment, many D-amino acids were obtained. D-amino acids are absent in the structure of a living organism.

“problems of chirality” As a result of the experiment, amino acids were obtained with different rotations (orientations) from the imaginary axis, which makes it almost impossible to combine them into a protein (b-ok)