slide 2

• Phenomenon of life.
• creationism;
• biogenesis hypothesis;
• panspermia hypothesis;
• the Oparin-Haldane hypothesis;
• Bibliography.
• Origin of life on earth

slide 3

What is life?

Life is a mode of existence of protein bodies, and this mode of existence consists essentially in the constant self-renewal of the chemical parts of these bodies.

Living bodies that exist on Earth are open, self-regulating and self-reproducing systems built from biopolymers - proteins and nucleic acids.

• F.Engels
• M.V.Volkenshtein

slide 4

Phenomenon of life

In the 20th century, numerous attempts were made to define life, reflecting the versatility of this process.

All definitions contained the following postulates, reflecting the essence of life:

• life is a special form of motion of matter;
• life is the metabolism and energy in the body;
• life is vital activity in the organism;
• life is self-reproduction in the body, which is ensured by the transfer of genetic information from generation to generation

Origin of life on earth

slide 5

Theories about the origin of life on Earth

creationism

• Vitalism (spontaneous generation)
• Panspermia
• Steady State Theory
• Biochemical evolution
• Biogenesis - the origin of life from life
• Abiogenesis - the origin of living things from non-living things

slide 6

Origin of life on earth

Hypotheses for the origin of life on Earth

Slide 7

The main hypotheses of the origin of life

• creationism

Life arose as the result of a divine creative act.

Michelangelo Buanarotti: The Creation of Adam

Slide 8

Hypothesis of spontaneous generation of life

Living beings can repeatedly appear from inanimate matter: fish from silt, worms from soil or meat, mice from rags, etc.

Ancient engravings: on the left - the transformation of fruits into fish and birds; on the right - in ducks.

Slide 9

Origin of life on earth

Hypotheses for the origin of life on Earth

2. Hypothesis of biogenesis

From ancient times to the middle of the 17th century. Scientists did not doubt the possibility of spontaneous generation of life. All living beings come from inanimate matter:

• fish - from silt;
• worms - from the soil;
• mice - from rags;
• flies - from rotten meat;
• fruits are birds.

Aristotle, studying eels, found that they are born from "sausages of silt formed from the friction of an adult fish against the bottom

Slide 10

Biogenesis hypothesis

The first blow to the idea of ​​spontaneous generation was caused by the experiments of the Italian scientist Francesco Redi, who in 1668 proved the impossibility of spontaneous generation of flies in rotting meat.

However, only in 1862, the French scientist Louis Pasteur finally refuted the hypothesis of spontaneous generation of life. The works of L. Pasteur made it possible to assert that the principle “All living things are from living things” is true for all known organisms on our planet, but they did not resolve the issue of the origin of life

Louis Pasteur

slide 11

1862

Louis Pasteur

Pasteur conducts an experiment with boiled broth in a sealed flask, from which an s-shaped tube was removed. The broth is sterile.

Pasteur removes the pipe and after a while life appears in the broth.

slide 12

Panspermia hypothesis

The concept of panspermia associated with the names of such prominent scientists as G. Helmholtz, W. Thompson (Lord Kelvin), S. Arrhenius, V.I. Vernadsky. These researchers believed that life is as eternal and ubiquitous as matter, and its germs are constantly traveling through space; Arrhenius, in particular, proved by calculations the fundamental possibility of transferring bacterial spores from planet to planet under the action of light pressure; it was also assumed that the substance of the Earth at the moment of its formation from the gas and dust cloud was already "infected" by the "germs of life" that were part of the latter.

slide 13

All attempts to detect living beings outside the Earth did not give a positive result. Repeated reports of findings of life traces on meteorites are based either on an erroneous interpretation of some bacterium-like inorganic inclusions, or on contamination of "heavenly stones" by terrestrial microorganisms.

In addition, the panspermia hypothesis does not solve the question of the origin of life in general, but only explains the origin of life on Earth.

Meteorite from Mars. NASA experts said that bacteria-like forms were found in its cracks. However, after a thorough check, it was found out that this is due to the method of electron microscopy used and the treatment of preparations with gold.

Slide 14

Steady State Hypothesis

Earth and life have always existed, forever. Species have always existed, but they could die out or change their numbers.

slide 15

OPARIN-HALDAIN THEORY 1924-1928

slide 16

Stages of the origin of life on the planet (according to Oparin):

• living cell
• Protobionts
• coacervates

Complex organic compounds (proteins, lipids, carbohydrates, nucleic acids)

Simple organic compounds (amino acids, sugars, etc.)

Simple inorganic compounds (H₂O, CO₂, N₂, NH₃), metal ions, mineral acids

Slide 17

Geophysical stage

"Big Bang".

• Formation of the solar system
• Formation of the shells of the Earth

Slide 18

• Complex of conditions on the primitive Earth
• Sufficiently high temperature of the planet's surface
• Active volcanic activity
• Lightning electrical discharges
• Ultraviolet radiation
• The result of their influence
• Synthesis of organic substances from inorganic compounds, proceeding in the aquatic environment

Slide 19

Abiogenic synthesis of organic compounds

• 1953 S. Miller and G. Urey synthesized organic compounds from inorganic ones under artificial conditions.
• Various organic compounds were formed in the aqueous phase: urea, lactic acid and some amino acids.

Slide 20

Theory of biochemical evolution

Conditions - the age of the Earth is 5-7 billion years, then on the surface of the Earth it is more than 4000 ° C, then it becomes less than 100 ° C, the water of the primary atmosphere formed the World Ocean.

"Reducing" primary atmosphere: H2, NH3, CH4, CO2, H2O

1 - abiogenic synthesis; experimentally proven synthesis of biological monomers

2 - synthesis of biopolymers (nucleic acids, polypeptides, etc.), formation of coacervates

3 - reproduction of molecules based on template synthesis - RNAs self-replicate, have a tertiary structure, and have catalytic activity

4 - double-stranded DNA provides more accurate replication and repair

5 - the appearance of coacervates covered with an outer membrane

slide 21

Probiont evolution

slide 22

Scheme of the emergence of eukaryotesTheory of symbiogenesis

1. Ancestral prokaryotic cells

2. Pre-eukaryotic cell with an isolated nucleus

3. Aerobic bacterium (precursor of mitochondria)

4. Cyanobacterium (precursor of chloroplast)

6. Mitochondria

7. Chloroplast

slide 23

biological stage

• Multicellular eukaryotes
• colonial organisms
• Unicellular eukaryotes
• Prokaryotes Prokaryotes
• heterotrophs autotrophs
• Probionts
• coacervates

slide 24

Disadvantages of the Oparin-Haldane hypothesis:

• how a qualitative leap from non-living to living took place. The probability of a random formation of a protein molecule, depending on the complexity of the protein, is approximately 10-500 - 10-300;
• for the self-production of nucleic acids, enzyme proteins are needed, and for the synthesis of proteins, nucleic acids.

Slide 25

Modern ideas about the origin of life on Earth.

In 1947, the English scientist John Bernal formulated the hypothesis of biopoiesis. He identified three main stages in the formation of life: the abiogenic occurrence of organic monomers (chemical), the formation of biological polymers (prebiological) and the emergence of the first organisms (biological).

slide 26

Biopoiesis hypothesis

• Stage of chemical evolution: abiogenic synthesis of organic monomers in the conditions of the primary atmosphere.
• Duration many millions and hundreds of millions of years
• Biological stage of evolution:
• formation of diverse groups of living organisms
• Stage of prebiological evolution: polymerization reactions.
• There was a formation of a protein-nuclein-lipoid complex (coacervates, hypercycles, probionts, progenots)

Slide 27

Conclusion

• So, there are 5 main hypotheses for the origin of life on Earth. Each of them has its own strengths and weaknesses, but none of them gives an exact answer to the question of the origin of life.
• The most convincing hypothesis of biochemical evolution, but it will never be fully proven.

Slide 28

Determine the correctness of judgments

1. Coacervates are the first living organisms on Earth.

2. The temperature of the Earth at the time of formation reached 1000˚С.

3. The composition of the primary atmosphere included gases: methane, ammonia, nitrogen, water vapor.

4. Coacervates are not able to absorb substances from the surrounding solution

5. At present, spontaneous generation of living organisms is impossible on Earth.

6. Condensation of water vapor began during the cooling of the planet.

7. Coacervates are fluid bubbles surrounded by protein films.

8. The first living organisms on Earth were heterotrophs.

9. The absence of an ozone screen in the atmosphere contributed to the formation of organic substances.

10. The sequence of protein formation is ammonia  amines  amino acids  proteins.

Slide 29

Bibliography

• Yablokov A. V., Yusufov A. G. Evolutionary doctrine (Darwinism): Proc. for biol. specialist. universities. - 3rd ed. - M .: Higher. school, 1989.
• Agapova O. V., Agapov V. I. Lectures on the concepts of modern natural science. University course. - Ryazan, 2000.
• Gorelov A. A. Concepts of modern natural science. – M.: Thought, 1997.
• Concepts of modern natural science. Series "Textbooks and teaching aids". - Rostov n / a, 1997.
• Dubnishcheva G.D. Concepts of modern natural science: Proc. for stud. universities / Ed. M. F. Zhukova. - Novosibirsk: YuKEA, 1997.
• Vernadsky V.I. Beginning and eternity of life. - M.: Respublika, 1989.
• Selye G. From dream to discovery. - M., 1987. Pp. 32.
• Soviet encyclopedic dictionary. - M.: Sov. encyclopedia, 1982.
• Marx K. and Engels F., Soch., 2nd ed., Vol. 20. M.: Thought, 1965.
• "Biological picture of the world".

slide 30

• Alexander Ivanovich Oparin (Materials for the biobibliography of scientists of the USSR, series of biochemistry, issue 3). M.; L., 1949. S. 5.
• Oparin A.I. Life, its nature, origin and development. M., 1960. S. 12.
• Rudenko A.P. Evolutionary catalysis and the problem of the origin of life // Interaction of methods of natural sciences in the knowledge of life. M., 1976 S. 220.

View all slides

What is life? Numerous definitions of life can be reduced to two concepts: 1. according to the first, life is determined by the substrate, the bearer of its properties. 2. according to the second, life is defined as a set of specific physical and chemical processes.

F. Engels The classic definition of F. Engels: “Life is a way of existence of protein bodies, the essential point of which is the constant exchange of substances with the external nature surrounding them, and with the cessation of this metabolism, life also stops, which leads to protein decomposition” can only formally be referred to the first category, since Engels had in mind not the proteins themselves, but the structures containing the protein.

M. V. Volkenshtein Based on the modern achievements of biological science, the Russian scientist M. V. Volkenshtein gave a new definition to the concept of life: “Living bodies that exist on Earth are open, self-regulating and self-reproducing systems built from biopolymers - proteins and nucleic acids ."

Conclusion: Conclusion: thus, according to Engels, the material carrier of life is protein, the mode of its existence is self-renewal, and the mechanism of self-renewal is metabolism. According to Volkenstein, the carrier of life is protein and nucleic acids, the essence of life as a self-reproducing system is connected with the ability to constantly exchange matter and energy with the environment.

Orderliness and complexity of living systems Life is qualitatively superior to other forms of existence of matter in terms of the diversity and complexity of chemical components and the dynamics of transformations occurring in living things. Living systems are characterized by a much higher level of structural and functional order in space and time. Living systems exchange energy, matter and information with the environment, thus being open systems. At the same time, unlike non-living systems, they do not equalize energy differences and restructure structures towards more probable forms, but continuously work “against equilibrium”.

Hypotheses of the origin of life At various times, the following hypotheses have been put forward regarding the origin of life on Earth: The hypothesis of biochemical evolution The hypothesis of panspermia The hypothesis of a stationary state of life The hypothesis of spontaneous generation The hypotheses of spontaneous generation and a stationary state are only of historical or philosophical interest, since the results of scientific research refute them. The panspermia hypothesis does not solve the fundamental issue of the origin of life, it only pushes it back to an even more foggy past of the Universe, although it cannot be excluded as a hypothesis about the beginning of life on Earth. Thus, the only generally accepted in science at the present time is the hypothesis of biochemical evolution.

The Spontaneous Generation Hypothesis This hypothesis was popularized in ancient China, Babylon, and ancient Egypt as an alternative to the creationism with which it coexisted. Aristotle (BC), who is often hailed as the founder of biology, held to the theory of the spontaneous generation of life. According to this hypothesis, certain “particles” of a substance contain some kind of “active principle”, which, under suitable conditions, can create a living organism. Aristotle was right in thinking that this active principle is contained in a fertilized egg, but mistakenly believed that it is also present in sunlight, mud and rotting meat. With the spread of Christianity, the theory of spontaneous generation of life fell out of favor, but this idea continued to exist somewhere in the background for many more centuries. The famous scientist Van Helmont described an experiment in which he allegedly created mice in three weeks. For this, a dirty shirt, a dark closet and a handful of wheat were needed. Van Helmont considered human sweat to be the active principle in the process of the birth of a mouse.

Francesco Redi In 1688, the Italian biologist and physician Francesco Redi approached the problem of the origin of life more rigorously and questioned the theory of spontaneous generation. Redi determined that the little white worms that appeared on rotting meat were fly larvae. After conducting a series of experiments, he received data confirming the idea that life can only arise from a previous life (the concept of biogenesis). These experiments, however, did not lead to the rejection of the idea of ​​spontaneous generation, and although this idea somewhat faded into the background, it continued to be the main version of the origin of life. While Redi's experiments seemed to disprove the spontaneous generation of flies, the early microscopic studies of Antonie van Leeuwenhoek strengthened this theory in the case of microorganisms. Leeuwenhoek himself did not enter into disputes between supporters of biogenesis and spontaneous generation, but his observations under the microscope provided food for both theories.

Louis Pasteur In 1860, French chemist Louis Pasteur took up the problem of the origin of life. Through his experiments, he proved that bacteria are ubiquitous, and that non-living materials can easily be contaminated by living things if they are not properly sterilized. The scientist boiled various media in water in which microorganisms could form. Additional boiling killed the microorganisms and their spores. Pasteur attached a sealed flask with a free end to the S-shaped tube. Spores of microorganisms settled on a curved tube and could not penetrate into the nutrient medium. A well-boiled nutrient medium remained sterile; no life was found in it, despite the fact that air access was provided. As a result of a series of experiments, Pasteur proved the validity of the theory of biogenesis and finally refuted the theory of spontaneous generation.

The Steady State Hypothesis of Life According to the Steady State Hypothesis, the Earth never came into being, but existed forever; it has always been capable of sustaining life, and if it has changed, it has changed very little. According to this version, species also never arose, they always existed, and each species has only two possibilities, either a change in numbers or extinction. However, the hypothesis of a stationary state fundamentally contradicts the data of modern astronomy, which indicate the finite time of existence of any stars and, accordingly, planetary systems around stars. According to modern estimates based on radioactive decay rates, the age of the Earth, the Sun, and the Solar System is ~4.6 billion years. Therefore, this hypothesis is not usually considered by academic science.

Supporters of this theory do not recognize that the presence or absence of certain fossil remains may indicate the time of appearance or extinction of a particular species, and cites coelacanth (coelacanth) as an example of a representative of lobe-finned fish. According to paleontological data, the crossopterans became extinct at the end of the Cretaceous. However, this conclusion had to be revised when living representatives of the crossopterygians were found in the Madagascar region. Proponents of the steady state theory argue that only by studying living species and comparing them with fossil remains can one conclude about extinction, and in this case it is very likely that it will turn out to be wrong. Using paleontological data to support the steady state theory, its proponents interpret the appearance of fossils in an ecological sense. So, for example, they explain the sudden appearance of a fossil species in a certain stratum by an increase in its population or its movement to places favorable for the preservation of remains. Theories of spontaneous generation and steady state are only of historical or philosophical interest, since the results of scientific research contradict the conclusions of these theories.

The hypothesis of panspermia by G. Richter Arrhenius According to this hypothesis, proposed in 1865 by the German scientist G. Richter and finally formulated by the Swedish scientist Arrhenius in 1895, life could be brought to Earth from space. The most likely hit of living organisms of extraterrestrial origin with meteorites and cosmic dust. This assumption is based on data on the high resistance of some organisms and their spores to radiation, high vacuum, low temperatures, and other influences. However, there are still no reliable facts confirming the extraterrestrial origin of microorganisms found in meteorites. But even if they got to Earth and gave rise to life on our planet, the question of the original origin of life would remain unanswered.

Hypothesis of biochemical evolution This hypothesis is based on the chemical specificity of life and links its origin with the history of the Earth. At present, the hypothesis of academician A. Oparin has received the widest recognition. It proceeds from the assumption of the gradual emergence of life on Earth from inorganic substances, through a long chemical evolution at the molecular level.

Hypothesis of Oparin Haldane In 1924, the future academician Oparin published the article "The Origin of Life", which in 1938 was translated into English and revived interest in the theory of spontaneous generation. Oparin suggested that in solutions of macromolecular compounds, zones of increased concentration can spontaneously form, which are relatively separated from the external environment and can maintain exchange with it. He called them Coacervate drops, or simply coacervates. According to Oparin, the process of the emergence of life can be divided into a number of stages: Abiogenic synthesis of the simplest organic compounds from inorganic ones. Abiogenic synthesis of polymers (proteins, carbohydrates, nucleic acids) from simple organic compounds. The formation of coacervates, as a separation in a solution of macromolecular substances in the form of a highly concentrated solution. Interaction of coacervates with the environment, similarity with living beings: growth, nutrition, respiration, metabolism, reproduction. The emergence of the genetic code, the membrane, the beginning of biological evolution.

The conditions for the beginning of the process of formation of protein structures have been established since the appearance of the primary ocean (broth). In the aquatic environment, derivatives of hydrocarbons could undergo complex chemical changes and transformations. As a result of this complication of molecules, more complex organic substances, namely carbohydrates, could be formed. According to Oparin's hypothesis, the formation of coacervate drops could be a further step towards the emergence of protein bodies. Under certain conditions, the aqueous shell of organic molecules acquired clear boundaries and separated the molecule from the surrounding solution. Molecules surrounded by an aqueous shell combined to form multimolecular coacervate complexes.

Coacervate droplets could also arise from simple mixing of various polymers. In this case, the self-assembly of polymer molecules into multimolecular formations, drops visible under an optical microscope, took place. Drops were able to absorb substances from the outside in the manner of open systems. When various catalysts (including enzymes) were included in coacervate droplets, various reactions occurred in them, in particular, polymerization of monomers coming from the environment. Due to this, the drops could increase in volume and weight, and then break up into daughter formations. Thus, coacervates could grow, multiply, and carry out metabolism. Further, coacervate drops were subjected to natural selection, which ensured their evolution.

The proof that the first and second stages can be carried out without the participation of living organisms was the experiments of S. Miller and S. Fox. In 1953, S. Fox conducted an experiment in which, by heating a mixture of amino acids, under normal atmospheric conditions, he obtained polypeptide chains.

In 1955, S. Miller created an installation with the help of which the conditions that existed on the primitive Earth were reproduced in miniature. The atmosphere in this model was a mixture of gaseous methane, water, ammonia, hydrogen, and carbon dioxide. This, according to scientists, was the primary atmosphere. Electrodes were built into the chamber with the atmosphere to produce electrical discharges that imitated lightning - one of the possible sources of energy for chemical reactions on our primitive Earth. As a result of the experiment, the simplest hydrocarbons, and even amino acids, were obtained.

To date, we cannot give an unambiguous answer about the origin of life. We can adhere to some concept or build our own hypothesis, but this does not mean that points of view that do not coincide with us are erroneous and do not have the right to exist. Everyone has the right to their own point of view, but at the same time must respect the opinions of others.

Lesson Objectives: To introduce the main hypotheses
the origin of life;
Develop the ability to summarize
conclusions, independently work with
popular science literature and
textbook;
Show how attitudes have changed
the emergence of life as
accumulation of knowledge.

Friedrich Engels

"Life is a way
the existence of protein
bodies, significant
moment of which
is permanent
metabolism with
external
nature, with
termination of this
metabolism
life ends,
that leads to
protein breakdown"

Theories of the origin of life on Earth exist
quite a lot, they can be divided into groups
1. Creationism
2. THEORY
SELF-GENERATION
3. THEORY OF STATIONARY
STATES
4. THEORY OF PANSPERMIA
5. THEORY OF BIOCHEMICAL EVOLUTION

Divine creation of the world.

Creationism (creation) -
religious and philosophical
concept in which everything
living beings and the planet itself
wholly created by God.
The hypothesis of creationism is outside the field of scientific
research,
So
how
she is
irrefutable:
cannot be scientifically proven, such as that God is not
created life, and that God created it.

Spontaneous generation of life

For millennia
people believed in spontaneous
the origin of life, considering it
the usual way of appearing
living beings from non-living
matter.
384-322 BC.
For example, Aristotle attributed lice
origin from meat, earthworms from silt
ponds.

Van Helmont (1577-1644)

described how, in three weeks, he created
mice.
For this, all you need is:
dirty shirt, dark closet and
a handful of wheat, and to process
began - human sweat.

The theory of spontaneous generation of life was defended by a German mathematician
and philosopher G. Leibniz (1646-1716), French naturalist
J. Buffon (1707-1788

Francesco Redi
1626 -1698 Italian
naturalist and physician.
He experimented with vessels
in which he put the meat, part
vessels left open, others
covered with cloth. in open vessels
flies laid eggs and there
fly larvae appeared in closed
there were no larvae in the vessels.

Thus was
finally proven
impossibility
spontaneous generation of living
organisms
L. Pasteur experiment
with curved flasks
necks

According to the hypothesis
stationary
states
The earth did not come into existence
but has existed forever.

Steady State Hypothesis

The earth will never
arose, and
existed forever; she is
has always been capable
support life and
if changed, then
very little; species also
have always existed. This
hypothesis is sometimes called
Eternism hypothesis (from
lat. eternus - eternal).
Nominated by German
scientist V. Preyer in
1880

Panspermia theory
Panspermia theory
It has
It is believed that life on Earth was brought from outside
with meteorites, comets or even UFOs
Swedish scientist S. Arrhenius
- author of the panspermia hypothesis
about the transfer of the germs of life
from one planet to another
meteorites or under
light pressure.
Nobel Prize 1903

Evidence for the hypothesis
panspermia:
The appearance of UFOs on Earth
Rock paintings depicting
objects that look like rockets and
astronauts
Encounters with aliens
Finds of meteorites containing
organic compounds

On a meteorite found in
Objects found in Antarctica
that can be identified
like traces of life
microorganisms from space

Proponents of the hypothesis
panspermia claims,
that life did not originate
Earth and elsewhere
universe without answering
question "how"?

In accordance with the hypothesis of biochemical evolution, life arose on Earth as a result of physical and chemical processes on

certain stage of development
Earth.

Theory of biochemical evolution
has the most supporters
among modern scientists

Alexander Ivanovich Oparin

In 1924 A. I. Oparin
work "Origin
life" put forward
coacervate hypothesis,
according to which the initial
stages of chemical evolution
were associated with
the formation of protein
structures.

In the future, the PRIMARY atmosphere of the Earth
re-formed from heavier
volcanic gases
It consisted of
water vapor H2O
carbon dioxide CO2
ammonia NH3
methane CH4

When the Earth's temperature dropped below 100°C, water vapor
began to condense, forming the oceans.
At this time, from the primary compounds formed
complex organic matter. Energy for fusion reactions
delivered lightning bolts and intense ultraviolet
radiation. The accumulation of substances was facilitated by the absence
oxygen and living organisms - consumers of organic matter

In 1924, the Russian scientist A.I. Oparin suggested
first concept of chemical evolution
In 1953, American scientists G. Urey and S. Miller in
conditions close to the atmosphere of a young
Earth, synthesized amino acids, nucleic
acids and simple sugars. In laboratory
conditions they exposed to electrical
discharges mixture of carbon dioxide, ammonia, methane,
hydrogen and water. During the experiment, there were
obtained biologically important organic
connections

Chemical
evolution is a process
formation
first organic
connections on earth

in the Earth's atmosphere and
waters
primary ocean
from inorganic
substances
formed
simple organic
substances:
amino acids, simple
carbohydrates, alcohols,
nitrogen bases,
fatty acid

Stanley Miller

The result is synthesis
amino acids, urea,
lactic acid
electrical discharges
(60000 V)
Pressure (nPa)
Temperature (+80˚С)

the stage of chemical evolution is the synthesis of polypeptide proteins that could have been formed in the waters of the primary ocean.

amino acids
Polypeptide proteins

Coacervates - embryos
primitive life

Properties of coacervates

selectively absorb from
environmental substances
Grow in size
Not capable of self-reproduction
Coacervate drops

the emergence of a membrane, nucleic acid molecules capable of self-replication

Probionts

John Haldane (1892-1964)

English biochemist,
geneticist and physiologist.
The author of the hypothesis
"Primary Bouillon"
one of
founders
population genetics

"Primary Broth"

Hypotheses of Abiogenesis: Hypothesis of Biochemical Evolution
Evolution at the level of RNA molecules in
coacervates has been going on for millions of years. So arose
the ancient world of RNA. Mutations and recombinations
in RNA populations created more and more
the diversity of this world.
At the same time, the links between
RNA and polypeptide synthesis,
providing them with more reliable
Existence.
The next step is DNA
double-stranded structure provides
stability and accurate replication
(doubling).

New discoveries of RNA functions

The discovery of new functions of RNA, or rather the so-called small RNA,
became a major scientific event. In 2003, new
confirmation that RNA molecules are not just intermediaries between DNA
and proteins in the process of protein synthesis. There are more and more
arguments in favor of the fact that RNAs are able to regulate ("turn on/
turn off") certain genes, thereby playing a crucial role in
the process of differentiation of the organism, as well as its current
vital activity.

Conclusion

Many of the theories that have been voiced today
use almost the same data, but
focus on different aspects. Scientific
theories can be super-fantastic, with
on the one hand, skeptical on the other.
Theological considerations also find
place within this framework, depending on
religious views of their authors. Each of
hypotheses have their own strengths and weaknesses.
but none of them gives an exact answer to the question of
the origin of life.

Hypotheses of the origin of life :

• creationism
• spontaneous generation
• steady state
• panspermia
• Biochemical

divine world creation.

• Creationism (creation) –

religious and philosophical

concept in which everything

living beings and the planet itself

generally created by some deity.

The hypothesis of creationism is out of the field of scientific research, since it is irrefutable: it is impossible to scientifically prove both that God did not create life, and that God created it.

Spontaneous generation of life

• For millennia

people believed in spontaneous

the origin of life, considering it

the usual way of appearing

living beings from non-living

384-322 BC.

For example, Aristotle attributed the origin of lice from meat, earthworms - from the silt of ponds.

Experiments Francesco Redi

• In 1688 an Italian biologist and

doctor F. Redi refuted

the possibility of the emergence of flies from

Redi covered the meat with muslin,

restricting airflow,

and showed that at the same time the meat does not

fly larvae appear. Francesco Redi

The Louis Pasteur Experience

• In 1860, as a result

series of experiments

French chemist

Louis Pasteur finally

refuted the theory

spontaneous generation

The principle "everything is only

from the living" has been proven!

• According to this hypothesis, the Earth never came into being, but existed forever; it has always been capable of sustaining life. The hypothesis fundamentally contradicts the data of modern astronomy, which indicate the finite time of existence of any stars and planetary systems. The age of the Earth is estimated at 4.6 billion years.

Hypothesis panspermia

• According to this hypothesis, life

on Earth appeared as a result

transfer from other planets of certain

germs of life (G. Richter in

Most likely to hit

to the planet of living organisms

of extraterrestrial origin

meteorites and space

dust. (no hard facts)

Hypothesis of biochemical evolution

• In 1924 the Russian academician

A.I. Oparin is one of the first

solved the problem of

life on earth. He claimed

that with powerful electrical

discharges and hard ultraviolet

radiation in the primary terrestrial

atmosphere could from

inorganic compounds

arise the simplest organic

substances needed for

the emergence of life.

The Stanley Miller Experience

• Oparin's prediction in 1953

confirmed by an American scientist

S. Miller, who, skipping

electrical discharges through

mixture of methane, ammonia, hydrogen

and water vapor under high pressure

nium and high temperature,

received in the laboratory

the simplest fatty acids

urea, acetic and formic

acids and several amino acids.

Stages of the origin of life on Earth:

First stage

Third stage

Second phase

Formation of organic substances from inorganic.

Formation from simple organic compounds in the waters of the primary ocean - proteins, fats, carbohydrates, nucleic acids. Formation of coacervates acting as open systems.

The appearance of matrix synthesis in coacervates, the emergence of self-reproduction based on matrix synthesis, first self-reproduction of RNA, then DNA.

The atmosphere and the ocean are saturated with aldehydes, alcohols, amino acids.

Stanley Miller and Sidney Fox designed an apparatus that contained the gases of the primary atmosphere. Through this mixture, they passed electrical discharges.

So amino acids were obtained abiogenically, other scientists received a set of all the monomers needed for the synthesis of biopolymers. It was the first stage of the origin of life on Earth.

Then, at the second stage, from simple organic compounds in the waters of the primary ocean, biopolymers were formed - proteins, fats, carbohydrates, nucleic acids, which spontaneously combined into drop coacervates.

Evolution at the level of RNA molecules in coacervates proceeded millions of years. This is how the ancient world of RNA came into being. Mutations and recombinations in RNA populations have created an ever-increasing variety of this world.

In parallel, the links between RNA and the synthesis of polypeptides are evolving, ensuring their more reliable existence.

At the next stage, DNA arises, their double-stranded structure ensures stability and accurate replication (doubling).

• At present, theories of spontaneous generation and steady state are only of historical and philosophical interest, since the results of scientific research contradict the conclusions of these theories.
• The theory of panspermia does not solve the fundamental question of the origin of life, although it cannot be excluded as a hypothesis about the sources of the origin of life on our planet.
• The theory of biochemical evolution is the subject of scientific research.

• 1. What hypotheses for the origin of life do you know?
• 2. Stages of the emergence of life on earth according to the theory of A.I. Oparin?
• 3. What experiments can prove the possibility of abiogenic synthesis of organic compounds?
• 4. What is the essence of the panspermia hypothesis?
• 5. What is the essence of the hypothesis of spontaneous generation?
• 6. What is the essence of the creationist hypothesis?

"Earth is our cosmic home" - Appeal to earthlings. Air shell of the Earth. Oceans and seas. atmospheric phenomena. The uniqueness of the earth. Human habitat. Wright brothers plane. Ant - 25. Science Day. Died under unexplained circumstances. Memory. Newspaper competition. The mechanism of life. Statement. Sailing ship. Aircraft of the Montgolfier brothers.

"Hypotheses about the origin of the Earth" - Theory of Immanuel Kant. space matter. Fire ball. scientific guess. Universe. Theory of Pierre Laplace. The science. The Bible forbids the practice of astrology. Broken stream. Nebula. Calculations. Modern ideas. Hypotheses about the origin of the Earth. Millions of plant and animal species. Ancient period.

"Theory of lithospheric plates" - The formation of a cold Earth. Gradual heating of the subsoil. Problem questions. Captive of the Sun. Emission of gases. Fold mountains. Niece of the Sun. Subsoil heating. Clash of the Titans. Hypotheses of the origin of the Earth. Scientific representations. Daughter of the Sun. Formation of the primary atmosphere. Cooling of the atmosphere. Freezing lava.

"Information about the Earth" - Acceleration of free fall = 9.78 m/s2. The structure of the bottom of the World Ocean: The third planet from the Sun is the Earth. Planet Earth. around its own axis. The composition of the Earth's atmosphere: Daily rotation of the Earth. Brief information about the planet Earth: 365 days 6 hours 9 minutes. The Moon is the only astronomical object outside the Earth that has been visited by man.

“Change of day and night” - Day is the movement of the sun across the sky from east to west. Every minute out of 60 seconds. Night is the dark time of the day. The change of night and day. The earth rotates on its axis in 24 hours. The human world also adjusts to the change of time of day. A day is exactly 24 hours long. In the morning the plants bloom, in the evening the buds close.

"Earth, Sun, Moon" - Due to the remoteness of the Sun, its rays fall almost parallel. Plan. Periods of the Moon's revolution. Apparent movement and phases of the moon. Orbit of the Moon and its perturbations. Movement of the Earth around the Sun. Covering the Moon with Earth. Coverings of the luminaries by the Moon. Earth and Moon. Eclipse conditions.

Total in the topic 22 presentations