THE MINISTRY OF EDUCATION OF THE RUSSIAN FEDERATION
SAINT-PETERSBURG STATE UNIVERSITY OF SERVICE AND ECONOMICS
Hypothesis of the origin of life on Earth
on the course: “the concept of modern natural science”
(C) D E R W A V E :
1. Introduction … … … … … … … … … … … … … … … … … … … … … …. p. 1
2. the concept of the origin of life … … … … … … … … … … … … p. 2
3. the hypothesis of the origin of life A.i. Oparin……………….. p. 5
4. Scientific view of life and its evolution. p. 8
5. geological era and the evolution of life………………………… p. 10
6. Used literature … … … … … … … … … … … … … … …. p. 12
One of the most difficult and at the same time interesting in contemporary natural science is the question of the origin of life. It is difficult because, when science is coming to the development problems of how to create a new, it turns out to be the limit of his abilities as a branch of culture based on the proof and experimental verification of claims.
Scholars today are not able to reproduce the process of life with the same accuracy as it was a few billion years ago. Even the most carefully choreographed experience will be a model experiment, deprived of a number of factors that accompanied the emergence of life on Earth. The difficulty is in the impossibility to conduct a direct experiment of creating life (the uniqueness of this process prevents the use of the scientific method).
Life on Earth is represented by an enormous variety of forms, which is characterized by the increasing complexity of structure and function. All living organisms have two characteristics: integrity and self-reference. The individual changes (ontoge-independent) organisms adapt to external conditions, generational change is evolutionary and historical in nature (financial logenez). Organisms have evolved the ability to relative independence, according to the external environment (autonomy). One of the main properties of any living organism, metabolism. In addition to the existing Government of signs of life are irritability, growth, razmno , variability, heritability. Every living organism as a aims to master-play.
2. the concept of the origin of life.
There are five concepts of life:
1. life has been created by the creator for a definite period of time to creationism.
2. life arose spontaneously from non-living matter (it was Aristotle who believed that living things can also occur as a result of the decomposition of soil).
3. the concept of a steady state in which life has always existed.
4. the concept of panspermii-the extraterrestrial origin of life;
5. the concept of the origin of life on Earth in the past as a result of the processes under the physical and chemical laws.
According to creationism the emergence of life refers to a certain event in the past which can be calculated. In 1650, Archbishop Usher of Ireland figured that God created the world in October, 4004 BC, and in 9:0 am 23 October. This number he got from the analysis of the ages and family relationships all mentioned in the Bible. However, by that time in the Middle East was already a developed civilization that proved by archeological research. However, the question of the creation of the world and man is not closed, as the texts of the Bible can be interpreted in different ways.
Aristotle, on the basis of information about the animals that came from soldiers of Alexander the great and merchants and travelers, formulated the idea of a gradual and continuous development of non-living and living things created the idea of a “ladder of nature”, in reference to the animal world. He did not doubt the procreation of frogs, mice and other small animals. Plato spoke of the procreation of beings from the land in the process of decay.
With the spread of Christianity the idea of spontaneous generation were declared heretical, and for a long time didn’t remind about it. Van Helmont came up with the recipe for mice from wheat and dirty laundry. Bacon also believed that the decay is the germ of a new birth. The idea of spontaneous generation supported Galileo, Descartes, Hegel, Harvey, Lamarck.
In 1688, an Italian biologist Francesco Redi in a series of experiments with open and closed vessels proved that appear in decaying meat white worms are larvae of flies, and formulated his principle: all living things-from a living. In 1860, Pasteur showed that bacteria can be everywhere and infect non-living substances, for getting rid of them need sterilization, called pasteurization.
The theory of panspermii (the hypothesis of the possibilities of life in the universe with a cosmic body on the other) offers no mechanism to explain the primary origin of life and moves the problem elsewhere in the universe. Liebig believed that “the atmosphere of celestial bodies, as well as rotating space nebulae can be considered as everlasting store lively form as a timeless plantation organic germs”, where life is dispersed in the form of the germ in the universe.
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Similarly, think Kelvin, Helmholtz and others. at the beginning of this century with the idea of radiopanspermii was made by Arrhenius. He described how the inhabited planets other beings are space particles, dust and spores of living organisms. They retain their vitality, flying in the space of the universe with light pressure. Once on the planet with suitable conditions for life, they start a new life on this planet.
Many supported this hypothesis, including Russians academicians Sergey Pavlovich Kostyčev (1877-1931), Lev Semyonovich Berg (1876-1950) and Pyotr Petrovich Lazarev (1878-1942).
To justify the panspermii typically use rock carvings depicting objects similar to rockets or astronauts, or appearance of a UFO. Flights of space vehicles destroyed faith in the existence of intelligent life on the planets of the solar system, which appeared after the opening of the channels on Mars, Schiaparelli (1877). But while traces of life on Mars is found.
At the end of the 60 ‘s, there has been a resurgence of interest in hypotheses panspermii. So, the geologist B. I. Čuvašov (questions of philosophy 1966) wrote that life in the universe, he believed that lasts forever.
When examining the substance of meteorites and comets have been discovered many predecessors live-organic compounds, hydrocyanic acid, water, formal′degit, cianogeny. In particular, formaldehyde has been detected in 60% of cases in 22 areas examined his clouds with a concentration of about 1 thousand molecules per cm3 fill the vast space. In 1975, the forerunners of the amino acids found in the Lunar soil and meteorites. Proponents of the hypothesis of life which rate them as “seeds”, seeded first in the land.
In the perception of the origin of life as a result of physical and chemical processes is important to the evolution of a living planet. In the view of many biologists, geologists and physicists, State Land during its existence all the time has changed. In very ancient times, the land was a hot planet, the temperature reached 5-8 thousand degrees. As the planet cooled, refractory metals and carbon kondensirovalis′ and formed a crust, which has not been smooth due to intense volcanic activity and possible developments of the emerging ground. The atmosphere of the primary Land deeply differed from the modern. Light gases hydrogen, helium, nitrogen, oxygen, argon and others are not held until the lack of dense planet, while the heavier compounds remain (water, ammonia, carbon dioxide, methane). Water remains in a gaseous state until the temperature dropped below 100onthe.
The chemical composition of our planet was formed as a result of cosmic evolution matter in the solar system, which had certain quantitative ratio of atoms. Therefore, current data on the ratio of atoms of chemical elements are important. Cosmic abundance of oxygen and hydrogen by an abundance of water and its various oxides. Relatively higher abundances of carbon was one of the reasons that determined the higher probability that life. The abundance of silicon, magnesium and iron promoted education in the Earth and meteorites silicates. Sources of information about the prevalence of elements are data on the composition of the Sun, meteorites, Lunar and planetary surfaces. Age of meteorites approximately corresponds to the age of the rocks, so it helps to restore the chemical composition of the Earth in the past and the changes caused by the emergence of life on Earth.
The scientific problem of life belongs to Engels, somewhat, that life is not suddenly, and was formed during the evolution of matter. In the same vein, and k.a. Timiryazev said: “we have to admit that living matter was carried out in the same way as all other processes by evolution. This process probably took place and in the transition from the inorganic world organic (1912).
3. the hypothesis of the origin of life A.i. Oparin
Even h. Darwin realized that life can arise only if there is no life. In 1871, he wrote: “But if …in a warm body of water containing all the ammonium salts and phosphorus and available light, heat, electricity, etc., are chemically formed protein capable of further, more complex transformations, then this stuff it would be immediately destroyed or absorbed, which was not possible in the period before the emergence of living beings “. Ascomycetes species, common now on Earth, would have used the newly emerging organic substances. Therefore, the emergence of life in our usual Earth conditions.
The second condition, in which life might arise, the absence of free oxygen in the atmosphere. This important discovery made the Russian scientist Alexander Oparin in 1924 (the same conclusion in 1929, came the English scientist j. B. S. Haldane). A.i. Oparin suggested that powerful electric discharges in the Earth’s atmosphere, which is 4-4 and 5 billion. years ago consisted of nitrogen, hydrogen, carbon dioxide, water vapor, ammonia, and possibly with the addition of hydrocyanic acid (found in the tails of comets), might be the simplest organic compounds necessary for life. Therefore, the surface organic matter could be accumulated without being oxidized. And now, on this planet they accumulate only in anoxic conditions, so there are peat, coal and petroleum. Creator of the materialistic hypothesis of life on Earth, Russian biochemist, academician Alexander Ivanovich Oparin (1894-1980) devoted his entire life to the problem of the origin of living things.
An American biologist j. Loeb in 1912, was the first to get out of a mixture of gases by an electric discharge is the simplest component of protein-amino acid glycine.
It is also possible that he received other glycine amino acids, but at the time was not yet methods to determine their small quantities.
Opening of Leba pass unnoticed, so the first abiogennyj synthesis of organic substances (i.e., going without the involvement of living organisms) of the random mixture of gases is credited to American scientist s. Miller and Urey. In 1953, they put the experiment on the programme, the Oparinym, and got under the influence of electric shock voltages up to 60 thousand. In imitating the zipper, from hydrogen, methane, ammonia and water vapor pressure in a few Pascals at t = 80° c a complex mixture of many dozens of organic substances. Among them was dominated by organic
(carboxylic) acid formic, acetic and Malic, aldehydes, amino acids (including glycine and alanine). Miller and Urey experiments have been tested for different gases and mixtures of different sources of energy (sunlight, ultraviolet and x-rays and heat). Organic substances occur in all cases. The Miller and Urey results prompted the scientists of different countries to study possible ways of predbiologičeskoj evolution. In 1957, Moscow hosted the first International Symposium on the origin of life.
According to data obtained recently by our scientists, the simplest organic compounds may also occur in outer space at a temperature close to absolute zero. In principle, the Earth could get abiogennye organic compound and as dowry when.
As a result of the Ocean turned into a complex solution of organic substances (so-called primary Ocean), which in principle could feed the anaerobic bacteria (organisms able to live and develop in the absence of free oxygen and energy for life through the breakdown of organic or inorganic substances). In addition to the amino acids and nucleic acids-the forerunners of the purine base, sugar, phosphates, etc.
However, the low molecular weight organic matter more to life. Basis of life are biopolymers-long molecules of proteins and nucleic acids, slagaûŝiesâ of-amino acids and nucleotides. Polymerization of the primary links in the aqueous solution not runs, so as to connect with each other two amino acids or nucleotides disrupted water molecule. The reaction in the water goes in the opposite direction. The speed of digestion (hydrolysis) of biopolymers would be greater than the speed of their synthesis. In the cytoplasm of our cells is the synthesis of biopolymers-complicated process under way with the energy of ATP. So it went, needed DNA, RNA and proteins, which are themselves the result of this process. It is clear that biopolymers could not occur in primary Ocean.
Perhaps the primary synthesis of biopolymers walked by freezing primary ocean or when heated dry the remainder. American Explorer Sw Fox, warming to 130 c, a dry mix of amino acids showed that in this case, the polymerization reaction is (the released water evaporates) and artificial proteinoidy are similar to proteins with up to 200 or more amino acids in the chain. Dissolved in water, they have the properties of proteins, were a breeding ground for bacteria and even catalysed (accelerate) some chemical reactions, as these enzymes. Perhaps they were in the predbiologičeskuû era of the hot slopes of volcanoes, and then rain washed them in the primary. There is this view that the synthesis of biopolymers went directly to the primary connection from the atmosphere and fell into the ocean in the form of primary particles.
The next phase of the estimated life-protokletki. A.i. Oparin showed that standing solutions of organic substances are formed koacervaty-microscopic “droplets”, limited to the semipermeable membrane-primary membrane. In case can concentrate organic matter, they are faster reactions, metabolism with the environment, and they may even share how bacteria. Such a process watched by dissolving artificial proteinoidov Fox, he called these balls microspheres.
In protokletkah like koacervatov or microspheres were polymerization reaction of nucleotides of a until protogenes-primary gene capable of catalyzing the emergence of a specific amino acid sequence, the first protein. Probably the first protein was the predecessor of the enzyme catalysing the synthesis of DNA or RNA. The protokletki, in which there is a primitive mechanism of heredity and protein synthesis, quicker sharing and took away all the organic matter of the primary. At this stage was natural selection for the speed of reproduction; any improvement of the biosynthesis of podhvatyvalos′ and the new protokletki squeezed all the previous ones.
The last stages of life-origin of Ribosomes and RNA, the genetic code and the energy of cells using ATP-have not yet been able to reproduce in the laboratory. All of these structures and processes are already among the most primitive of microorganisms, and the principle of their structure and function has not changed in the history of the Earth. Therefore, the final stage of the origin of life, we can still reconstruct only the presumably-as long as it will not be duplicated in experiments.
So far we can only say that the emergence of life in the earthly version it took relatively little time-less than one billion. years. For 3.8 billion. years ago, there were the first microorganisms, which happened all the diversity of life on Earth.
Life arose on Earth abiogennym by. Currently, living only occurs from the living (solid, origin). To the re-emergence of life on Earth.
4. Scientific view of life and its evolution
Darwin described the driving forces of evolution of living nature. He tried to understand and explain the real nature of the internal contradictions of the organic world. His theory not only explains the nature of these conflicts, but also specifies the ways in which they are resolved in the world of animals and plants.
A significant place in all the writings of Darwin, and in particular, in “the origin of species, are evidence of the fact of organic evolution.
Now it is generally accepted that all living things are coming off with chemicals group of proteins, among which a special provision are nucleoprotein. It is a compound of protein and nucleic acids. Nucleoprotein make up the main com-ponent of plant and animal cell nucleus. Research in the field of molecular biology has shown that the nucleic acid, you are responsible for many important processes of living organisms. The special role played by macromolecules deoxyribonucleic acid (DNA) and ribonucleic acid. (RNA). A molecule of DNA in conjunction with other substances, cells determines the synthesis of protein and enzymes that regulate metabolism. Protein and nucleoprotein (DNA and RNA) are a required component of all biological, such organisms. Therefore, from the point of view of chemical evolution, and they are the basis of all known life on Earth, biologists and related forms.
In addition between the inanimate and living nature there is eternal, continuous communication. “Between the bigoted and lively substance there is continuous, never terminated connection which can be expressed as a continuous current of atoms from the nutrient of the living matter in kosnoe biosphere substance, and vice versa. This nutrient flow of atoms is called a living substance. It is expressed in nonstop never breathing, nutrition, reproduction of, etc. “.
On the unity of nature shows and the differential nature of the body of animals and plants. Thus, the oneness of the world of organisms manifests as their chemical composition and structure, and operations. This fact did not escape the attention of naturalists. The idea of the similarities of living organisms led j. Cuvier to the teachings about the types of Animal Kingdom. In Dahl’s ahead, she got in the writings of k. Baer, e. Examples, a. o. Kovalevsky, i. i. Mechnikov, who argued that the gathering of animal production cannot be explained as anything other than a community of origin.
On the unity of the organic world and indicates the existence of so-called intermediate forms, which include animals and plants, are transitional, intermediate between major taksonami.
In the organic world, there are no rigid boundaries between the units of the future generations. At the same time, the boundaries between species are always real. Darwin is a great place to view and speciation. It is not by chance that in the title of his work made “origin of species”. As a major unit of organization type is central to evolutionary theory. Task èvolûcion, the theory is an explanation of the origin of life and changing actual species of animals and plants that inhabit the land.
Evidence of the evolution of life and the similarity of the belly, which is expressed in their position, the ratio in general terms and in the development of similar začatka of the embryo. Similar bodies are called homologous organs. Evolutionary Theo-Riya explains the similarity of the commonality of origin than of form nivaemyh, while proponents of creationist concepts interpreted this similarity as the will of the creator, from groups of animals on a specific plan.
Confirmation of the idea of evolution is a reflection of the history of the development of organisms on their structure and the processes of embryonic development, as well as the geographic distribution of organisms.
A special place in the development and deepening of the stavlenij takes evolutionary genetics. The remaining genes are beginning to be addressed in 20-30-ies of XX century in connection with the fuss of knoveniem population and evolutionary genetics. Elucidation of the structure of the population has a new look at the evolution of traditional processes, played at the population level. Genetics has made it possible to trace the main stages of èvolûci million from a new trait in the population prior to the emergence of a new kind. She brought to the study of species within the mikroèvolûcionnogo level, the precise experimental methods.
The basic unit of heredity-gene, a stretch of DNA that determines the development of elements of elementary signs. The basic evolutionary unit must meet the following requirements: limb Division;
the ability to change the biological changes of the ancestral generations; the reality and specificity of existence in the present-conditions. This unit is considered to be the population evolution — the basic unit of evolution, and inheritance of the population is a fundamental evolutionary phenomenon. It reflects the change in genotypic structure of the ass of the ventilation. The gene is prone to mutations, heritable modifications of individual animals. The mutation is discrete code change heirs of such information. There are gene, chromosome, gene, and vneâdernye types of mutations.
The occurrence of mutations supports a very high degree of genetic diversity of natural populations. But, playing the role of “provider” of basic material, the registration process of Muta directs the course of evolutionary change, it has a probabilistic, statistical nature.
Patterns of evolution is reflected in the life of an individual, but the driving forces of evolution contained within the system of individuals, in this case. The resolution of controversies population forms the basis of all evolution and defines the transformation of the body as an integral part of the population. Relationship between organisms in a population are complex. The investigation is hampered by the fact that, in addition to vnutripopulâcionnyh interactions of organisms are the influence of other populations of other species and even wider — environmental conditions.
5. geological era and the evolution of life
Under the influence of evolutionary theory and geologists had to revise their view about the history of our planet. Organic world has evolved over billions of years, together with the environment in which he had to exist, i.e. together with the Earth. Therefore, unable to understand the evolution of life without evolution of the Earth and vice versa. A.o. Kovalevsky’s brother Vladimir Kovalevsky (1842-1883) put evolutionary theory as the basis of paleontology is the science of fossil organisms.
The first traces of organic residues geologists found in ancient sediments of the proterozojskoj geological era, covering a huge amount of time is 700 million years. The land at the time was almost entirely covered by ocean. It was inhabited by bacteria, protozoa, algae, primitive marine animals. Evolution then was so slow that tens of millions of years passed until the organic world any noticeable change.
In the Paleozoic era (lasting approximately 365 million years) the evolution of all life was already at a more rapid pace. Large areas of land were formed, which were terrestrial plants. Especially rapidly evolved ferns: they formed a giant primeval forests. Ocean animals too were improved, resulting in a huge crustacean fish. In the coal (carbon) period, which falls in the heyday of the Paleozoic fauna and flora, the amphibians. And in the Permian, zaveršavšij Paleozoic era and beginning the Mesozoic (removed from us at 185 million years) there were reptiles.
Faster the flora and fauna of the Earth began to develop in the Mesozoic era. Already in the early reptiles were to dominate the land. There were also the first mammals-marsupials. Universal distribution was received by coniferous trees, having a variety of birds and mammals.
About 70 million years ago was cainozoic era. Types of mammals and birds have continued to improve. In the plant world the dominant role belonged to flowering. Formed in plant and animal species that inhabit the Earth.
With the emergence of man about 2 million years ago, begins a period of the Cenozoic era, the Quaternary or some. People in the geological time scale is the perfect babe. After 2 million years for nature-extremely small period. The most significant event in the Cenozoic era has been the emergence of a large number of crops and domestic animals. All of them are the result of human creativity, sentient being, capable of purposeful activities.
If the theory of evolution, Darwin, studied the experiences of breeders, armed with scientific theory breeders learned to breed new varieties more quickly and with greater dedication. Here the special role the Russian scientist Nikolai Vavilov (1887-1943), razrabotavšemu doctrine about the origin of cultivated plants. the evolution of the living thing going on, but under the influence of man.
We know now that the usefulness of organic forms is not something ahead of this, and the result of a long and complex process of development of matter, and therefore the usefulness of organic forms is relative. People now actively changes the living nature. Increasing human interference in the processes of nature raises new serious issues that can be resolved only on the condition that the person will take care of the natural environment, to save those thin
ratios in the biosphere, created it for millions of years of evolution of life on Earth.
Teaching about the Biosphere has created a remarkable scientist Vladimir Vernadsky (1863-1945). Under the biosphere scientist knew the thin shell of the Earth, in which processes are under the direct influence of living organisms.
The biosphere is located at the junction of all other Land-shells of the lithosphere, hydrosphere and atmosphere, and plays a crucial role in the exchange of substances between them. Huge amounts of oxygen, carbon, nitrogen, hydrogen and other elements to constantly go through living organisms on Earth. V.i. Vernadsky showed that there is virtually no elements in the periodic table, which has been turned into a living substance of the planet and do not stand out from it when it breaks down. Therefore, the face of the Earth as a celestial body actually created life. Vernadsky was the first to show what a pivotal role of the geological world living substance.
He focused on the huge geological and human roles. He showed that the future of biosphere- noosphere, the sphere of mind. He believed in the power of the human mind, believed that are increasingly invading the natural evolutionary processes, people will be able to steer the evolution of living in such a way as to make our planet more beautiful and richer.
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