How did life come about?

How did evolution begin and how did inanimate matter become living matter?

By: Iris Frey
From: Galileo - the Israeli magazine for ecological science, July/August 11 issue, 1995

Notes: Dr. Iris Fry teaches history and philosophy of biology at the Cohen Institute for History and Philosophy of Science and Ideas at Tel Aviv University and at the Department of General Studies at the Technion.

How did life come about?
By: Iris Frey

In the middle of the last century (1859) Charles Darwin published his book "On the Origin of Species". The book changed our view of the animal world and caused a great stir. The upheaval manifested itself not only in the natural sciences; It influenced man's view of himself and his place in the world, and his social, cultural and philosophical views. The "Origin of Species" included a huge amount of data from various fields of research, which substantiated the claim that the different types of living creatures were not created individually in the form we know today, but rather depended on and developed from each other through natural processes. Darwin's theory was revolutionary not only because of the claim that evolution did take place, but mainly thanks to the mechanism that Darwin proposed as the driving force behind the evolutionary processes. This mechanism - natural selection - is based on the variation between different individuals of living creatures belonging to the same population, and indicates the relative advantage certain individuals have in different natural environments. Following Darwin, it was possible to describe the biological processes without using concepts such as plan and purpose, and relying only on material mechanisms. Evidence of the profound significance of this change, which goes far beyond the field of biology itself, we find in the fact that even today, almost one hundred and fifty years after the publication of Darwin's book, the evolutionary, naturalistic worldview still struggles with attacks aimed at it from non-scientific directions.

Darwin and the origin of life

One of the important assumptions of the theory of evolution is that all the creatures that exist today on earth, originate from a common ancestor. In his book, Darwin refers to one primordial form, or to a few primordial forms from which all species of living beings evolved and evolved. However, he does not deal with the question of how those initial forms developed. Admittedly, at the end of "The Origin of Species" Darwin makes use of the terms of the book of Genesis - he writes about life forces that were "reduced by the Creator" in the same primordial form from which the entire animal world depended, on the abundance of its creatures. However, in a letter he sent to a friend a few years later, he explicitly clarifies that he actually meant to indicate that this was an enigmatic, completely unknown process. Darwin assumed that the science of his time was unable to give an answer to the question of how the transition from inanimate matter to that primordial life happened. However, he pondered a lot on the subject of the origin of life and in one of his letters he even put forward the hypothesis, which seemed to him extremely daring, that life began in a mikveh-water that contained inorganic compounds such as carbon dioxide, ammonia and phosphorus salts, from which they were formed - under the influence of light and heat. Electrical breakdowns, etc. - simple organic compounds, from which life evolved.

Spontaneous formation

In the second half of the 19th century, the question that agitated both the academic world and the general public was whether it was possible for spontaneous life to arise from non-living matter. During hundreds of years, since ancient times, during the Middle Ages and even during the 16th and 17th centuries, no one doubted, not even the best thinkers and naturalists, that living creatures are created not only through normal reproductive processes. The explanation was that they are formed even without parents, spontaneously and suddenly from mud and tree bark, from organic secretions and decaying materials, under the influence of the sun's heat and suitable humidity conditions. We are talking about self-creation (generation) that takes place in plants, worms, insects, fish, frogs, birds and more.

The soil of the Nile was considered particularly fertile for the spontaneous creation of crocodiles and snakes, as, for example, William Shakespeare recounts in his play "Antony and Cleopatra". In the 12th century, the story of the goose trees was common in Europe. The naturalists of the time reported in their writings about the creation of geese by burning certain pine trees under the influence of sea water. By the way, this belief was not only widespread, but also very useful: believing Christians are prohibited from eating meat on Fridays, a reminder of the crucifixion. And here, since the source of the geese was - according to belief - sea water, they could be eaten, because of their status as "fish" even on Fridays.

And another, much later example - from the 17th century: a widely publicized prescription by the Flemish physician and chemist van Helmont, for the spontaneous creation, without parents, of mice: pluck wheat kernels and place them in a closed box with a sweaty shirt for twenty one days. The steam released from the shirt, which contains the principle of life, will "do the job".

In the different periods, the phenomenon of the spontaneous creation of life received different explanations according to the spirit of the time. The history of these ideas is an instructive example of the influence of presuppositions - philosophical, religious and political - on scientific thought. There were thinkers and naturalists, both in ancient Greece and in modern times, who believed that there is no fundamental difference between inanimate matter and living beings. They explained the occurrence of spontaneous creation with the help of the movements of the particles of matter and the laws of motion of matter. The church also supported, for centuries, the idea of ​​self-creation of life. The Christian theologians believed in the command given to the earth and the heat of the sun at the creation of the world, to create life at all times. Alternatively, other theologians based the parentless creation on the direct intervention of God, imprinting the life principle in inanimate matter. For various scientific, philosophical and religious reasons, the church began to fight passionately against the idea of ​​creating life in this way from the 17th century onwards. Belief in spontaneous creation had its ups and downs in the 17th and 18th centuries, following the accumulation of anatomical and microscopic data that testified to the great complexity of living creatures. At that time, experiments were also carried out in which various researchers were able to show that spontaneous creation of various creatures, for example insects, is not possible. Since the 18th century, there has been talk of self-creation of tiny, microscopic creatures only.

Louis Pasteur - an independent researcher?

In the 60s of the 19th century, the scientific world and the intellectual elite in France were shocked when the debate heated up about the possibility of the existence of self-creation of microscopic creatures: in experiments conducted by naturalist Felix Pouchet, the apparently spontaneous creation of microorganisms in organic solutions was demonstrated. On the other hand, there were the experiments of the great French researcher Louis Pasteur, which contradicted the results of Pusha. It was Pasteur's experiments that ultimately closed the door on the idea of ​​spontaneous creation.

Pasteur's brilliant experiments are still used today as a model for experimental scientific work. However, Pasteur's work, like all scientific work, was shaped by considerations of ideology and a philosophical worldview. He gave a clear expression to this in a lecture at the Sorbonne in 1846, in which he discussed the philosophical and religious implications of the controversy surrounding the question of spontaneous creation. Pasteur, who belonged to the political establishment in France and supported the dominant church and anti-materialist ideology, presented in his lecture the key question on the subject of the origin of life: Can matter organize itself? Can inanimate matter organize itself to form a living system? Pasteur answered the question in the negative - his experiments proved beyond any doubt, he said, that life can only be created from previous lives, and that every individual is necessarily a descendant of parents. Years later, after the fall of the Second Empire in 1871, when the political atmosphere in France changed and became more liberal, Pasteur publicly expressed his doubts and claimed that he was not convinced that spontaneous creation was not possible.

In the last decades of the 19th century, the supporters of Darwin's theory faced a difficult problem. At the time, it seemed that Pasteur's experiments did close the door on the possibility of creating life from inanimate matter even when it comes to microscopic life forms. However, at the same time it was clear to them (as it was also clear to Darwin himself) that the logical expansion of the theory of evolution towards the assumption that at an early stage in the history of the earth a transition from inanimate matter to a living system was required. Indeed, some of the prominent Darwinists of the end of the century, for example the Englishman Thomas Huxley and the German Ernst Haeckel, hypothesized that a kind of spontaneous creation took place on the surface of the ancient earth, from simple inorganic and organic compounds to living systems. This hypothesis is fueled, among other things, by the concept that was accepted at that time according to which the protoplasm, from which the living cell is built, is a fairly simple substance in chemical terms. Huxley even claimed to have found on the bottom of the ocean evidence of the existence of primitive protoplasm containing the remains of an ancient primitive creature. Later it turned out that this is an artifact - a "find" of the test method itself, which in this case is the chemical processes of preserving the samples from the seabed.

At the end of the century, cytological techniques (discussing the structure of the cell) were developed that discovered various components of the living cell and emphasized the importance of the cell nucleus. Also, at the end of the 19th century and the beginning of the 20th century, biochemistry developed and many enzymes responsible for various processes in the cell were identified. Following these developments, the theoretical concept changed completely. Now consider the cell a very complex system. Any assumption that talks about the creation of a living cell following random chemical reactions between simple molecules was seen as completely unfounded by most scientists of the time.

Simulated solution - life is eternal

Against the background of this impasse in the question of the origin of life, some of the best scientists of the late 19th century proposed a kind of solution, which is actually the cancellation of the question itself. Some well-known physicists, chemists and physiologists argued that it is inconceivable that life arose from inanimate matter on the surface of the earth, and that it is much more likely to assume that life is eternal, like the eternity of matter and the eternity of the universe. Somewhere in the universe, they claimed, in places where favorable conditions prevail, life has always existed. They are carried in the universe as spores or seeds and reached the earth via meteorites, or in various other ways. These ideas, the various versions of which were called the "panspermia theory", expressed the philosophical assumption that life cannot be created from non-living matter, since these are two fundamentally different essences.

Since most scientists of the beginning of the 20th century did not see the Panspermia theory as a satisfactory solution, and since no reasonable chemical mechanisms were proposed to explain the development of life on Earth, the subject was almost completely ignored in the first decades of the current century. This was later testified by one of the famous geneticists of the time, Hermann Muller, that the general feeling was that it was a taboo that should not be touched at all.

Bacteria in the spacecraft

We will now make a jump in time and reach the year 1981. In this year, a book called "Life itself" was published, which presented a theory known as intentional panspermia. space, from another planet inhabited by intelligent beings belonging to a more developed civilization than ours. The author of the book is one of the famous scientists of our time, Francis Crick, who was a partner in the discovery of the structure of DNA. Does within the framework of his theory, which appears to be a science fiction story, give Crick An answer to the question of how life originated - if not here, then elsewhere? Contrary to the old ideas of panspermia, Crick does not claim the eternity of life, and certainly should not be attributed to him as a principled denial of the possibility of life arising from inanimate matter. His purpose was to point out the great confusion that still characterizes the question of the origin of life , and raising awareness of the complex and difficult nature of the problem.

Unlike Francis Crick, most researchers today still ask how life on Earth originated. Since the XNUMXs, there has been active practical research into the question of the formation of kehim, in which astrophysicists, geophysicists, meteorologists, oceanographers, organic chemists, biochemists and molecular biology researchers have joined together. It is clear to everyone that there is no possibility of an exact reconstruction of unique events that took place in the distant past, in which life was created, but it is possible to propose plausible scenarios, based on the laws of nature and the accumulated knowledge. And yet, about one hundred and thirty years since Pasteur presented the key question regarding the ability of matter to organize itself, it is still one of the most difficult questions in biology. Furthermore, in the opinion of some of the most renowned biochemists, precisely the extraordinary achievements of molecular biology, which reveal to us the enormous complexity of living systems, have made the question even more difficult.

We will now try to find out three questions for ourselves: First, how did the subject turn from a taboo into a legitimate scientific question? Second, what is hindering at this stage a satisfactory solution to the question? And thirdly, what, nevertheless, are the achievements of the research and what are the directions of the obvious solutions?

Oprin-Holden hypothesis

Two articles bearing the name "On the origin of life" that appeared, independently, in the 1924s, articles that were ahead of their time, were the ones that stood in the background of the breakthrough that took place later. In 1929 an article by the Russian biochemist Alexander Oparin was published in the Soviet Union, and in 1936 an article by the biochemist and geneticist John Bardon Sanderson Holden appeared in England. Both articles for the first time raised unique hypotheses regarding the conditions that prevailed on the surface of the ancient earth, conditions that allowed the creation of organic compounds. They also proposed mechanisms - different from each other - for the stages of transition from these organic materials to a primitive living system through chemical evolution. In XNUMX Oprin published his book - "On the Origin of Life" - in which he expanded and deepened his hypotheses and arguments. Only after World War II did the book have a real impact on the international science community.

Oprin based his ideas on new findings revealed by biochemistry, as well as on important developments in inorganic and organic chemistry. The proteins were characterized as colloidal substances - substances that exhibit a special behavior in solution, while being able to form a kind of cell-like systems that are differentiated from their surroundings. The properties of the colloids, in which Oprin saw a kind of intermediate stages between the chemical and the biological, allowed him to propose a testable script to describe the origin of life.

Holden, on the other hand, drew his inspiration from the young field of genetics and especially from the discovery of viruses. While Orrin focused on life as a system of interwoven chemical reactions, a self-perpetuating system, Holden saw reproduction as the central feature of life.

New data began to accumulate regarding the chemical composition of the universe. It turned out that the most common chemical element is hydrogen. Following these discoveries, new hypotheses were raised regarding the nature of the ancient atmosphere on Earth. Oprin and Holden put forward the claim, bold for its time, that the early atmosphere of the Earth did not contain oxygen, but was a recirculating atmosphere, that is, rich in hydrogen-containing compounds. Under these conditions, they suggested, the creation of simple organic compounds became possible. Later, more and more complex substances were created, which accumulated in the "primitive soup". Oprin and Holden saw these initial stages as a necessary condition for the emergence of life. Another important point they raised was this: in the absence of oxygen, the ozone layer that dampens the radiation was also absent. The strong ultraviolet radiation could therefore be an important source of energy for various chemical reactions. Starting in the 1963s, the Oprin-Holden hypothesis became a guiding framework for research in the field of early life. By the way, Oprin and Holden met for the first time only in XNUMX at an international conference whose theme was the origin of life, held in Florida under the auspices of the American space agency NASA.

The third alternative

Between the theory proposed by Oprin and that of Holden there were differences in concept and details. Fundamentally, however, both presented a common message: they presented an alternative to the two principled approaches that were known before: the vitalist-religious option, which saw life and inanimate matter as two separate categories, and the simplistic mechanistic option, which was unable to stand up to the enormous complexity of living systems, even the most primitive ones.

The materialist-evolutionary approach of Oprin and Holden presents the cosmic, chemical and biological evolution processes as one sequence, but it also recognizes the unique properties of living systems and tries to explain them through material mechanisms that can lead to the self-organization of matter. Several historians of science have suggested that it is no coincidence that the three people who contributed to the establishment of this approach, the pioneers Oprin and Holden, and the one who joined in the XNUMXs and XNUMXs, the English physicist John Bernall, were Marxists. They argued that the development of life is an integral part of the evolution of the material world, but, at the same time, one must recognize different laws operating at different levels of material organization.

Miller's experiment - a scientific field was born

Oprin was the first to clearly define possible processes for the formation of living systems. After World War II, biochemists began to investigate the different stages that oprin suggested. The most famous of these experiments, an experiment that actually established the field of experimental research on the origin of life, was that of the American chemist Stanley Miller (Miller) in 1953. Miller succeeded in creating a number of organic substances, including amino acids, which are the building blocks of proteins, from a mixture of Ammonia, water and hydrogen - a mixture that represented the ancient recycling atmosphere. As a source of energy, Miller used electrical discharges, which represented ancient sources of energy, such as lightning. Following Miller's experiment, a boom in research began - experimental groups in many laboratories around the world were able to demonstrate, under varied conditions, the creation of many compounds that are biologically important, and these compounds were also able to create more complex substances. Also, periodicals in the field began to appear, textbooks on the subject were published, conferences with many participants began to be held - in short, the scientific field that discusses the question of the origin of life was founded.

Many laboratory personnel and theoreticians continued Oprin's direction - the biochemical direction. According to this direction, the living system is defined as a cellular unit, with a sufficient degree of complexity for carrying out metabolic processes while maintaining certain constant values, despite the changing environmental conditions. In the XNUMXs, most of the efforts were aimed at recreating the processes by which the proteins were formed. It was assumed that at the stage of the formation of life, the proteins were responsible for the main cellular activities, while enabling reproduction processes and development of the primary cellular units. At the same time, and following Holden's hypotheses, another direction of research developed that drew its inspiration from the field of genetics, according to which a living entity is defined with the help of its genetic activity - the ability to self-replicate and the ability of the genetic material to undergo mutations. At the beginning, in the XNUMXs and XNUMXs, genetic theories assumed that the "living molecules" - the genes - were created by chance from inorganic material. It was clear to everyone that this was indeed an event with a very small probability, but - so they argued - the very long periods of time available to the process also made the improbable real. However, the reliance on a "successful case", meaning an event whose probability is extremely small, did not allow for the direction of this research to build an experimental set-up and propose testable models similar to Oprin's.

This situation changed following the decoding of the DNA structure by James Watson and Francis Crick in 1953 and after the discovery of the genetic code in the sixties. Following these impressive achievements in the field of molecular biology, the genetic hypotheses about the origin of life took on a more detailed form. Now it was possible to plan and carry out many experiments to examine the possibility of the appearance of the first gene and the possibility of its replication.

The chicken and the egg question

With the development of molecular biology, the dispute between the biochemical approach and the genetic approach was formulated in the form of a question: what preceded what in the origin of life? Were the pioneers the proteins, responsible as enzymes for all metabolic processes, or were they preceded by the nucleic acids, responsible for self-replication and the transfer of hereditary information? All living systems known to us are characterized by both chemical languages ​​- the language of enzyme activity and the language of hereditary information. However, due to the enormous complexity of both the proteins and the nucleic acids, it cannot be imagined that with the origin of life, a primary creation of proteins and nucleic acids was possible at the same time. This fact entangles us in a "chicken and egg" style problem. In the cells we know, the creation of proteins depends on the existence of nucleic acids: the proteins are produced according to the information contained in DNA (while sharing several types of the nucleic acid RNA). However, the creation of the nucleic acids and their activity, both depend on the activity of proteins. The nucleic acids are all created with the help of enzymes, and all the processes of translating the hereditary material into proteins are done with the help of highly complex enzyme systems. How could the proteins have been formed for the first time without nucleic acids? And how could the nucleic acids have been formed first, before the proteins appeared? In the fifties, attempts were made to attribute to proteins the ability to carry information, and to point to them as the origin of the biogenetic process. Over the years, the scale has tilted more and more towards nucleic acids. It is clear, in any case, that solving the question of how life originated is, to a large extent, solving a problem along the lines of the chicken and the egg problem.

Starting in the early XNUMXs and for about two decades, it seemed that the study of the origin of life had many successes. Research groups have succeeded, in many laboratories, in creating amino acids very easily, and there have also been achievements in creating some of the building blocks of nucleic acids, DNA and RNA. Various researchers even managed to link, under the appropriate conditions, these building blocks into long chains - polymers. (Proteins and nucleic acids are polymers). In a key experiment carried out by the American chemist Sidney Fox, a kind of proteins were obtained from amino acids that even demonstrated the ability to act as weak enzymes. In many laboratories, short nucleic acid-like chains (oligo-nucleotides) were also obtained. Following the deciphering of the DNA structure and the discovery of the chemical principles that enable the replication of the genetic material, many experiments were conducted to demonstrate the self-replication capacity of nucleic acid segments. A number of laboratories reported at the time that there was some success in replicating nucleic acid segments even without the presence of enzymes.

The great principle importance of the self-replication experiments was in trying to demonstrate that a group of self-replicating polymers can, under certain conditions, exhibit natural selection processes, similar to the behavior of living beings during evolution.

In the self-replication of nucleic acids, an exact copy of the order of the building blocks in DNA or RNA is made. The copy is exact, but not completely. From time to time mistakes are made in the copying process - these are the mutations. The polymers carrying the mutations obtained in the copying processes sometimes have advantages compared to the normal copies, in that they are more stable, their replication rate is faster, etc. Since all the polymers in the population compete for the same building blocks, there is a possibility of natural selection between them. According to many researchers, the principle of natural selection, which is able to operate already in molecular systems, even before the existence of life, is the principle responsible for molecular evolution and the emergence of life. It is appropriate to mention here the decisive contribution of the German chemist, son-in-law of the Nobel Prize, Manfred Eigen, to the development and application of the concepts of molecular evolution to the study of the origin of life.

Back to square one?

During the last two decades, following the accumulation of new data in various branches of science, the Oprin-Holden hypothesis has been called into question. Many researchers claim today that the ancient atmosphere was apparently not recirculating to the extent that allowed the creation of a sufficient amount of organic compounds, and that, therefore, the experiments of Stanley Miller and his many successors lost their validity. The English chemist Cairns-Smith completely rejects the accepted script for the origin of life; He claims that life did not begin at all with organic chemistry - chemistry of carbon compounds, which is more complicated, but with inorganic chemistry, which is much simpler. Cairn-Smith thought that the first "organisms" were made of clay crystals containing zinc and other metals. The mineral, when it multiplies, can "bequeath" to its descendants additional "information" on top of the previous layer.

Before us is a kind of process of self-replication in which mistakes also fall and thus materials are created that have a relative advantage over their surroundings. Cairn-Smith hypothesizes that in the processes of reproduction and natural selection of minerals, "organisms" were also created that learned to create organic compounds on their surface, because this gave them an advantage. Gradually there was no need for a cellular-organic scaffold and there was a takeover of organic polymers such as proteins and nucleic acids.

According to another theory, which is more accepted today, most of the organic origin materials were "imported" to the ancient Earth on meteorites and comets that bombarded the Earth after it was formed (see: "The Origin of Life on Earth", Galileo, 2 p. 10). More and more findings indicate the existence of many organic compounds in outer space, both in interstellar clouds of dust and gas - clouds from which new stars are formed, and in meteorites and comets. An interesting finding is the organic content of a meteorite that fell in Murchison, Australia in 1969, which includes, among other things, amino acids in a composition and ratios very reminiscent of the results of Stanley Miller's experiments. It should be noted, however, that other researchers were able to demonstrate the synthesis of organic substances even under non-reducing conditions
especially.

Life - since when?

Another problem is related to the "schedule" of the process of life formation. Until recently they thought of very long periods of time available to the process of formation of the first living systems. This helped, as mentioned, to the claim that an initial key molecule could have formed by chance. It now turns out that the window of time during which life apparently formed was very short relative to the age of the Earth, which was created about four and a half billion years ago. During the first half of a billion years, the data show, due to very high temperatures and intense meteorite bombardment, life formation or survival did not take into account (some argue, therefore, that life evolved at the bottom of the oceans). However, according to the fossil evidence, living things whose bodies are built as cells existed about 3.6 billion years ago. In many ancient rocks, stratified structures called stromatolites were found, similar to structures that today produce large bacterial colonies. Fossils of bacteria have also been found in ancient rocks in Australia and Greenland. Some researchers claim, based on the measurement of various carbon-isotope ratios, that carbon-fixative life in photosynthesis existed as early as 3.8 billion years ago. The conclusion is that the window of time lasted no more than half a billion years, and some say much less - a real geological "blink of an eye". It is therefore clear that if we do not want to assume that the origin of life involved some "miracle", any reasonable scenario must be based on fast mechanisms with a relatively high probability.

The world of RNA

In an attempt to deal with the question of the chicken and the egg, a number of biochemists in the early 1989s came up with an idea based on weighty chemical reasoning, according to which the nucleic acid of the RNA type (RNA) functioned in the ancient world as both an "egg" and a "chicken". In this context, we mention the contribution of the chemist Leslie Orgel, but it was only in the early eighties that it became clear that there was truth in this idea - and then a significant breakthrough in research became possible. Two American researchers identified in certain living creatures RNA molecules capable of performing what was previously considered the exclusive function of proteins - enzymatic activity. Initially, only a limited enzymatic activity was discovered, but recently new discoveries have been made regarding the varied enzymatic capacity of the RNA molecules, among other things - probably also, in the construction of proteins. For the discovery of ribozymes - that's how these RNA molecules are called - Maglihan, Cech and Altman received the Nobel Prize in XNUMX, and then the term "RNA world" was also coined, which became the leading hypothesis in the research origin of life

Many researchers do believe today that the origin of life included at some early stage a "world" without proteins, which preceded the "world" we know, where the creation of proteins is possible based on the information of the north in the nucleic acid. However - contrary to the enthusiasm that arose following the discovery of ribozymes - it is becoming clear that the problem is still far from being solved. We still do not know how the first RNA molecules themselves were created. The hypothesis that a successful chance meeting of the "correct" building blocks gave rise to an RNA molecule capable of functioning is rejected as improbable. The various solutions offered today, around which research will most likely be concentrated in the coming years, include a proposal of different "worlds" that preceded the "RNA world", worlds where relatively simple substances were created that later enabled the creation of a kind of nucleic acids capable of replicating and acting as an enzyme which helps in replication (see picture). The Nobel Prize-winning Belgian biochemist Christian de Duve describes chemical processes that enabled the creation of short polymers from single amino acids, polymers that functioned as enzymes and eventually led to the world of RNA. Several scenarios assign an important role to various minerals, which could have functioned as inorganic enzymes, and catalyzed the creation of polymers.

A distinction must be made between ribozymes - RNA molecules that have enzymatic capacity, and ribosomes - organelles in which the building of proteins takes place in the cell.

The continuation - in research

How, then, did life originate on earth? It turns out that this question is still waiting to be answered. We still do not know how material processes can lead to the creation of an organic whole, whose components are mutually dependent on each other for their existence and activity. If we compare the living cell, even the simplest, to an arch whose stones support each other - a comparison made by Cairns-Smith, we can say that we are looking for the scaffolding on which the arch was built. Throughout history, the question of the formation of life aroused great interest, but was not seen as a mystery; Precisely when scientific knowledge developed, especially during the 19th century, the question of the origin of life wore a veil of mystery. Only in the last few decades has the mystery become a scientific question that can be tested experimentally, and it is indeed being studied vigorously.

We started the revolution of Darwin's theory of evolution; The question of the origin of life is currently one of the central focuses in the struggle to establish this revolution. Those who call themselves "creationists" - the members of the various religions - want to revive the story of the Book of Genesis in order to seemingly solve the problem of the origin of life. Against these attempts it must be remembered that the only way open to science, despite all the difficulties, is the continuation of the research.

for further reading:

John Horgan, "In the beginning", Scientific American, February 1991
pp. 117-125

Leslie Orgel, "The Origin of Life on Earth". Scientific American
. October 1994, pp. 53-61