The ladder of creation

During the ascent of man there were two traditions of explanation that developed in parallel. One of them analyzed the physical structure of the world. The second focused on the study of life processes, their fine details, the great difference in them and the cycles in the life of the individual and the species, from birth to death. These two traditions met and united only after the theory of evolution was formulated

Jacob Brunovsky

In the fifties of the nineteenth century, two scholars, independently of each other, formulated the theory of evolution through natural selection. One was Charles Darwin. The second Alfred Russel Wallace. Both had a certain scientific education, but mostly they were drawn to the study of the flora and fauna. Darwin studied medicine for two years at the University of Edinburgh. Then his father, a rich doctor, suggested that he prepare for the priesthood in the Anglican Church, and for that he sent him to Cambridge. Wells was the son of poor parents. He left school at the age of fourteen, later attended classes at labor training institutes in London and Leicester and worked as a land surveyor and school teacher.

During the ascent of man there were two traditions of explanation that developed in parallel. One of them analyzed the physical structure of the world. The second focused on the study of life processes, their fine details, the great difference in them and the cycles in the life of the individual and the species, from birth to death. These two traditions met and united only after the theory of evolution was formulated, because before that there was something paradoxical about the phenomenon of life, which no one knew how to solve.

The paradoxical side of the life sciences, the thing that distinguishes them from the physical sciences, is the versatility of life and its presence everywhere in nature. We see the paradox around us in birds, trees, grasses, snails and thousands of other creatures. And the paradox is this: the phenomenon of life is embodied in so many different forms that there is no escaping the assumption that there is a considerable amount of coincidence in them. And yet there is so much uniformity in the phenomenon of life that there is no doubt that they are directed by great necessity.

Therefore it is no wonder that biology, as we understand it, began in the eighteenth and nineteenth centuries with the actions of nature lovers, of people who liked to circle the countryside and follow the behavior of birds, of clergymen, doctors and gentlemen who lived comfortably in their dormitories the villagers I tend to call them by the inclusive name 'Victorian gentlemen', because in my opinion it is not a coincidence that the theory of evolution came to the mind of two different people at the same time, who lived in the same period and in the same culture - the culture of the time of Queen Victoria in England.

Charles Darwin was in his early twenties when the Admiralty decided to send a research vessel, the Beagle, to map the coast of South America. Darwin was offered an unpaid position as a research biologist on this ship. The position was offered to him on the recommendation of Hansel, the botany professor at Cambridge, who befriended Darwin, even though he was not particularly interested in botany, and what excited him was collecting beetles.

Darwin wrote about this hobby:
I will give you an example of my eagerness to speak. One day I peeled off a piece of bark from one of the trees and saw two rare beetles under it. While I was holding them, one in my right hand and one in my left hand, I suddenly saw a third beetle of a different kind, and since I in no way wanted to lose it, I put the beetle in my right hand into my mouth.

Darwin's father opposed the trip, and the captain of the Beagle did not approve of his participation either. But Wagwood, Darwin's uncle, intervened in his favor and the matter was settled. The Beagle sailed on December 27, 1831.

The five years Darwin spent on board this ship made him a different person. His interest in the study of birds, flowers, and the animal world in general in his surroundings in England, became a passionate love in South America. During his journey, Darwin became convinced that species develop differently if they are isolated from each other. This means that species are not immutable. However, the mechanism of the incarnations was still not clear to him. This was the case in 1836.

Two years later, Darwin found the explanation for the evolution of species, but he was reluctant to publish it. It is possible that he would have postponed the publication until the end of his life if another person had not reached the same conclusions. It was a completely different kind of person, but he reached his conclusions almost exactly in the same way of research and thinking as Darwin. This man is almost forgotten, but he had a decisive role in formulating the theory of evolution by way of natural selection.

The man's name was Alfred Russell Wells. He was of huge stature and came from a family reminiscent of the Dickens stories, and which was the comic contrast to the severe conservatism of the Darwin family. In 1836 Wells was in his teens. He was born in 1823, and was therefore fourteen years younger than Darwin. Even then his life was not easy. He himself tells about it:

If my father had been a man of means... my life would have been completely different. Although even then I would have been somewhat interested in science, I don't think I would have traveled to the unknown forests of the Amazon region to study nature there and make a living collecting animals.

Before his trip to South America, Wells worked in England as a land surveyor, a profession that did not require a university education. He learned the profession from his older brother, who died in 1846 from a cold, due to traveling in an open train car of the third class, on his return from the meeting of a royal committee, which discussed the rivalry between different railway companies.

On the occasion of his work, Wells spent most of his time in the open air, and probably then he became interested in plants and insects. While working in Leicester he befriended a man with similar interests, who was more widely educated than himself. His new friend surprised Wells, in his book he collected several hundred different species of beetles in the vicinity of Leicester, and that there must be many more species that have yet to be discovered. Wells writes about this:

If they had asked me before how many species of beetles there were in the vicinity of the city, I would have said: maybe fifty... Now I know that there are probably about a thousand different species within a radius of ten words.

This was a kind of revelation for Wells, and it influenced not only the course of his life but also the life of his friend, the naturalist E. and. HW Bates, who later carried out important studies on the phenomenon of camouflage (mimicry) in the world of insects.

Wells had to earn his living by the hour. Luckily for him, these were good times for land surveyors, because the daring men who built the railroads in the XNUMXs needed surveyors. Wells was employed in surveying for the construction of a railway in the Neath Valley in South Wales. He was a conscientious technician, like his late brother and as was typical in the Victorian era, and he did his job with dedication. However, in his heart was the suspicion, and rightly so, that he was actually only used as a tool in the power game between the investors. The purpose of most of the measurements was only to prevent the capture of a certain area by another 'robber noble' among the railroad builders. According to Wells's calculations, only a tenth of all those railway lines, for which he made measurements during those years, were actually built.

But life in the Welsh landscape was a delight for a nature lover like him. Wells now researched and collected independently, and his admiration for the versatility he discovered in nature grew day by day. All the days of his life he liked to remember the happy times he spent in Wills.

Even when the work was a lot I was always free on Sunday. I took long walks in the mountains. The collection box was always with me, and when I returned from the trips the box was full of treasures... So I lived the joy that every discovery of a new way of life gives to the nature lover. That joy was no less than the admiration that attacked me later in the Amazon region every time I caught a new butterfly.

On one of his weekend trips, Wells found a cave with an underground river, and decided to spend the night there under the sky. It was as if he was already preparing, unconsciously, for the life that awaited him in the tropical forest.

This time we wanted to try to sleep under the dome of the sky without shelter, without a bed, except what nature invented for us... I think we decided on purpose, not to make any preparations but to spend the night there, as if we happened to arrive in some place in an unknown country and had to sleep there.

Wells didn't actually sleep much that night.

When he reached the age of twenty-five, Wells decided to devote all his time to the study of nature. It was a strange profession in Victorian times. In order to make a living, Wells will now have to collect specimens of animals in foreign countries and sell them to museums and private collectors in England. His friend Bitz decided to join him. Both set out in 1848, with a joint capital of one hundred pounds sterling. They sailed to South America and traveled about 1,500 kilometers across the Amazon, up to the city of Manaus, where the Rio Negro River joins the Amazon.

Until then, Wells had only traveled as far as Wills. Still, the exotic landscape of the Amazons did not terrify him. From the moment he arrived there he felt great self-confidence, and his descriptions testify to that. Here, for example, is what he writes about the prize in his book: Narrative of Travel on the Amazon and Rio Negro, which appeared five years later:

The common black prize is common there in large numbers. But these birds suffer from a lack of food. When they find no other food, they are forced to make do with the palm fruits in the forest.
Based on my many observations, I am convinced that these birds depend on their sense of sight in their search for food, and not at all on their sense of smell.

The two friends parted ways in Manaus. Wells continued his journey across the Rio Negro, looking for places that had not been visited by naturalists before him. If he wanted to make a living from collecting animals he had to find specimens of unknown species, or at least of rare species. The river overflowed after the rains so Wells and his Indians could sail across it deep into the heart of the forest. The branches of the trees almost touched the water. The gloom did indeed frighten Wells, but at the same time he felt uplifted, seeing the wealth of multifaceted forms in the forest. He wondered what such a forest would look like from the air.

What can be said about the tropical vegetation is that the number of species and the richness of the variety of forms exceed what we know in the temperate regions. It seems to me that there is no country in the world that has such a quantity of plant material on its surface as in the Amazon Valley. Except for very small parts, this valley is covered with a thick and high primeval forest, a continuous and wide-ranging forest, the like of which there is no other on the face of the earth. All the glory of these forests could only be seen from a hot air balloon, which would float slowly above the floral carpet of the moving emirs. Such pleasure may be reserved for the passengers of the future.

Wells was both excited and scared when he first entered an Indian village. But it is typical of Wells, because in the end he got a lot of pleasure from this visit.

An unexpected feeling of surprise and pleasure caused me my first meeting with a man in a natural state, with a wild man who had not yet been spoiled... Each one did his work or amused himself in a way that was unlike that of the white man. They walked freely, as befits independent forest-dwellers, without noticing us, strangers of a different race.

In every detail of their behavior there was an expression of originality and self-confidence, such as the animals of the forest. Independently of civilization, they lived their lives in their own way, as countless generations had lived before them before America was discovered.

It became clear to Wells, that the Indians are not cruel but happy to help, and he shared with them the work of collecting animal specimens.

During the time I spent here (forty days), I collected at least forty species of butterflies which were new to me, besides a considerable number of other animals.
One day they brought me a very strange little alligator. It belonged to a rare species (Caiman gibbus) and had many rows of conical dorsal scales. I skinned him and gutted him, while half a dozen Indians followed my action with great pleasure.

While enjoying the pleasure and trouble of life in the forest, the burning question began to flash in Wells' sharp mind: how was this versatility created? How to explain the great difference in details together with the great similarity in the general plan? Like Darwin, Wells was also surprised by the differences between closely related species. And like Darwin, he also began to wonder why these species evolved in such a different way.

There is no branch of natural science more interesting or instructive than the study of the geographical distribution of animals.
There are places only fifty or a hundred miles apart, yet you will find in one of them species of insects and birds that you will not find in the other. Surely there is some boundary line that determines the domain of each species. There must be some special sign indicating that line, which no species is allowed to cross.

Wells was always drawn to geographical problems. At a later period, when working in the Malay Archipelago, Wells showed that the animals of the western islands resembled the species found in Asia, while the animals of the eastern islands resembled the species found in Australia. The line that separates them is known to this day as the 'co-wells'.

A similar degree of meticulous attention that Wells devoted to the phenomena of nature, was also unique to looking at human beings and the source of the differences between them. At a time when the Victorians called the Amazon population 'savages', Wells showed a rare sympathy for their culture. He understood the meaning they had for language, invention and custom. He may have been the first to understand that the distance between their culture and ours is smaller than we are used to thinking. After the principle of natural selection dawned on him, the closeness between the two cultures seemed to him to be self-evident even from a biological point of view.

All that was in the power of natural selection was to give the wild man a brain that would in some measure surpass that of the ape. On the other hand, we see that he has a mind that falls only slightly short of that of all thinkers. With the appearance of man, therefore, a creature arose, in which the hidden power called 'intelligence' is infinitely more important than the structure of the body.

Wells felt a strong sympathy for the Indians, and he composed an idyllic description of their way of life during the days he lived in their village of Jaoita in 1851. At this point, the language of his diary turns into poetry - or at least, into rhymes:

There is an Indian village. around it
The dark, eternal, endless forest stretches,
its multifarious cost.

I lived here for a while, the only white person
Among about two hundred people.

Every day he would call them to a certain job. Now they are going
cut down some beautiful trees in the forest, or go out in a boat,
With rod, spear and arrow, to hunt fish.

The broad palm leaves serve as thatch for them
Impenetrable to the winter rains and storms.

The women dig to get tubers out of anihot
and laboriously prepare bread from them.

All of them bathe every day, morning and evening, in the stream
and wading in the sparkling waves, like mermaids.

The little children walk naked.
The boys and men wear only a narrow belt.
What a pleasure to see the naked boys!

Their beautifully shaped limbs, their fresh, smooth, reddish-brown skin,
And all their movements mean grace and health.
They compete by running, shouting and jumping
Or swim in the sweeping stream and dive in its waters.

I pity the boys of England, whose active limbs
bound in clothes fastened to the body.

And even more I pity the girls of England,
whose waist and cantor are imprisoned
in the torture device called a corset.

I would like to be an Indian, live here contentedly,
to fish and hunt, row a boat
and see my children grow up like Ofri-Eyal,
healthy in body and happy in part,
Rich without capital and happy without gold.

This sympathy for Indians was completely different from Charles Darwin's feelings when he first saw South American Indians. Darwin was horrified when he met the natives of Tierra del Fuego. This feeling is expressed in his words and his writings in his book The Voyage of the Beagle. There is no doubt that the brutal climate affected the customs of the natives of Tierra del Fuego. But photographs from the nineteenth century prove that it was not as animalistic as it seemed to Darwin. In Cape Town, on his way back home, Darwin, together with the captain of the ship Beagle, published a pamphlet in which the two praised the action of the missionaries, who tried to change the way of life of the savages.

Wells spent four years in the Amazon basin. Then he packed his collections and set off to return to England. On the journey to Manaus, Wells says:

The fever and chills attacked me again. For several days my condition was very bad. It rained almost all the time, and it was very difficult to take care of the birds and the many other animals because there was a lot of crowding in the boat, and as long as it rained it was not possible to keep them clean, as it should be. Every day some of them died. Sometimes I got tired of everyone. But since I collected them I decided to persist in taking care of them.
Out of a hundred animals I bought, or received as a gift, only thirty-four remain.

From the beginning it was therefore an unsuccessful journey. Wells was always a down-on-his-luck man.

On the 10th of June we left Manaus, and that was the beginning of a very unhappy journey for me. When I boarded the ship, after saying goodbye to my friend, I found that I was missing the toucan. He probably flew off the ship, and since no one noticed him he must have drowned.

The choice of the ship was not successful, because it was carrying a cargo of flammable resin. After a three-week journey, on August 6, 1852, a fire broke out on the ship.

I went down to the cells to see what could be saved. The air in the cabin was very hot and full of smoke. I took my watch, a small tin box with some cotton and some old notebooks, in which I drew various plants and animals. That's all I got on board. Many clothes and a large bag with records and charts remained in my cells, but I did not dare to go down to it again. In fact, I felt a kind of indifference to any attempt to save things, a feeling that is difficult for me to explain now. Finally the captain ordered everyone to get into the boats. He himself was the last to abandon ship.

What a pleasure I would look at every rare and strange insect I added to my collections! How many times have I penetrated the forest in spite of the fever harassing me, and have come to my reward when I have found some beautiful creature of an unknown species! How many places where the foot of no European except myself had set foot, would remind me of the rare insects and birds which these places have contributed to my collections!

And now all is lost. I have not even a single example left to testify to the unknown lands I have traveled through and to remind me of the wild spectacles I have witnessed. But I knew that there was no use in lamenting what was lost, and I tried not to reflect on what could have been but to think about the state of things as they were.

Like Darwin in his time, Wells also returned from the tropical region convinced that closely related species are created by splitting from one species, which is their common ancestor. But it was still not clear to him what caused the development in different forms. He did not know, because Darwin found the explanation two years after he returned to England from his voyage on the Beagle. Darwin said that in 1838 he read the book by Rev. Thomas Robert Malthus Essay on the Principle of Population. He said he read the book for pleasure, meaning he did not consider it part of professional reading material. However, one of Malthus's ideas surprised him. Malthus claimed that the population grew at a faster rate than the food supply. If this is true for animals, then they have to compete with each other to stay alive. This means that nature acts as a selective factor, killing the weak and creating new species adapted to their environment from those left behind.

'Well, I finally had a theory that I could work with,' said Darwin. Perhaps you think that a person who says such a thing will immediately start writing articles and lecturing. But that's not what Darwin did. For four years he did not even put his theory on paper. Only in 1842 did he compose a first draft, thirty-five pages written in pencil. Two years later he expanded the draft to one hundred and thirty pages written in ink. And he deposited this draft, along with a sum of money and instructions to his wife about the publication of the article after his death.

In a letter to his wife, dated July 5, 1844, Darwin writes:

'I have just finished my essay on the theory of species... I am writing to you to formally express to you my last and most important request. I am certain that you will honor my request, as if it had been legally included in my will, and that you will devote the sum of 400 pounds sterling to the publication of the article and that you will take care of it yourself, or with the help of Hensley (Jwood) in its distribution. My desire is that the article be handed over to someone who understands the matter, who will be willing to improve and expand it for the aforementioned amount.

As for the editing of the paper, Mr. (Charles) Lyell is the most suitable man, if he will agree to do the work. I think he will find the job pleasant and will also learn some new things for him.
Dr. (Joseph Dilton) Hawker was also very suitable for this.'

I have the feeling that Darwin would have preferred to die before publishing his teachings, provided that after his death his right of birth would be recognized. After all, there is evidence of a strange character in this. Darwin knew he was about to say things that would shock the public (including his wife). He himself was also shocked by these things. His hypochondria (some mishap during his trip to the tropics was used as an excuse), the bottles of medicine that filled his house, the closed and stuffy air in his study, the need to sleep in the afternoon, the hesitation to write, the refusal to argue in public - all these things indicate a person who does not dare to appear before the public .

Of course, young Wells had no such inhibitions. Despite all the troubles he went through, he left in 1854 full of energy for the Far East. For eight years he wandered the Malay Archipelago and collected specimens of animals, to sell them in England. Wells has long been convinced that species are not immutable. In 1855 he published a treatise called On the Law which has regulated the Introduction of New Species, and since then 'I have not let go of the problem, how the changes in species came about'.

In February 1858, Wells fell ill while on the small volcanic island of Tarnata in the Moluccas group, the Spice Islands, between New Guinea and Borneo. He suffered from a recurring fever, and attacks of fever and chills to knitting confused his thinking. Then, one feverish night, Wells remembered Malthus's book, and suddenly the same explanation that had occurred to Darwin years before was revealed to him.

I asked myself: why do some die while others stay alive? And the answer was clear: usually, the fittest are the ones who stay alive. The most robust, they are the ones who recover from diseases. The strongest, the fastest, or the most naked, are the ones who escape from their enemies. The most skilled hunters or the creatures with the best digestive capacity are the ones who survive starvation, and so on.

It suddenly became clear to me that the variation that characterizes every living being provides the material from which the most qualified ones emerged to continue the competition, after all those less adapted to the given conditions had been weeded out.

Suddenly the idea of ​​the survival of the fittest flashed through me. The more I thought about it, the more I became convinced that I had finally found the same law of nature that I had been looking for for so long, the law that explained the origin of species... I waited impatiently for the attack of fever to pass, so that I could put my idea on paper. And indeed I did so that evening, and on the following two evenings I wrote a detailed article, which I decided to send to Darwin, by mail, which was to be published in a day or two.

Wells knew that Charles Darwin was interested in the subject, and he offered him to show the article to Lyell as well if he found there was any truth in it.

Darwin received Wells' article in his study at Down House after four months, on June 18, 1858. In his embarrassment, Darwin did not know what to do. For twenty years of painstaking work, he quietly collected facts to strengthen his theory, and here comes from a place outside the settlement a surprising article, about which Darwin wrote in the day:

I have never seen a more amazing coincidence. If Wells had the draft I wrote in 1842, he could not have summarized it better.

Darwin's friends decided to solve the problem, Lyell and Hooker, who knew some of Darwin's work, made arrangements with the Linnean Society so that Wells' article and Darwin's article would be read at its upcoming meeting in London in July, in the absence of the two authors.

The articles did not receive any response, but from now on Darwin had to come out of hiding. And so it happened that Darwin's Origin of Species, published in 1859, immediately became a sensational bestseller.

The theory of evolution by way of natural selection is surely the most important innovation in science brought about by the nineteenth century. After all the foolish protests and insipid jokes inspired by the book on the origin of species had evaporated, the animal world had a new face. It is now seen as a world in constant motion. Creation was no longer static, it was changing over time, although in a completely different way than the physical processes. Ten million years ago the physical world was exactly as it is today, and its laws then were the same as they are today. But in the living world things were completely different. Thus, for example, there was still no human being on earth ten million years ago. Unlike physics, every biological generalization was only valid for a limited period of time. It is evolution that created and creates originality and innovation in the universe.

If the theory of evolution is true, then the genealogy of each of us reaches back to the beginning of life on earth. Wells and Darwin studied forms of behavior, bones as they are today, and fossils as they were in their time, to set scores on the path that led to Adi and Adiqi. However, forms of behavior, bones and fossils, are already complicated living systems, consisting of simpler units that preceded them in time. And what are these primary units? Probably chemical molecules characteristic of the phenomenon of life.

When we look back to find the origin of life, we are actually looking deep into the chemical processes common to all living things. The blood now flowing through my fingers is a result of the first molecules, from three million years ago, that had the ability to breed, and to reach me the blood went through millions of stages. This is evolution as we understand it. In the processes of evolution, heredity played a part (a phenomenon that Wells and Darwin did not understand) and also chemical structure (a field in which French scientists excelled more than British naturalists). The explanations come from different fields, but the equal side of them is that they describe the species as separating one by one, step by step. This form of description was undertaken after the acceptance of the theory of evolution. From then on it was no longer possible to believe that the act of creating life could repeat itself in our days or at any other time.

To the claim of the theory of evolution, that certain species of animals appeared in a period closer to us than other species, its critics usually answered with verses from the Bible. But most people believed that creation did not end in the six days of Genesis. It was believed that crocodiles are born from the mud of the Nile under the influence of the heat of the sun. It was a common opinion that mice formed themselves in piles of dirty baggage; And no one doubted that the origin of blue flies is in rotten meat; And that larvae are created, necessarily, inside the apples, because if not, how did they get there? The assumption was that all these creatures come into the world spontaneously, without the help of parents.

The legends about creatures coming into the world spontaneously are very old, and they still have believers, even though Louis Pasteur disproved them in the sixties of the last century. A large part of his work was done by Pasteur at his family home in Arbois in the French Jura mountains, where he loved to return every year. He studied fermentation, especially milk fermentation (the term 'pasteurization' reminds us of this work of his). But in 1863, when he was forty years old and at the height of his power, Pasteur was asked by Napoleon III, Emperor of France, to check the problem of malfunctions in wine fermentation. He dealt with the matter for two years and solved it. There is an irony in the fact that the wines of these years were the best ever produced. The wines of the year 1864 were especially praised, and it was said about them that there was no like them in any other year.

'Wine is a sea full of organisms,' Pasteur said. 'Thanks to some of them it exists, and because of others it breaks down.' There are two surprising things here. One is that Pasteur discovered organisms that lived without oxygen. At the time, their existence was only a nuisance to the winegrowers, but in the meantime it became clear that they were important for understanding the beginning of life on earth, at a time when there was still no oxygen in the atmosphere. The second thing is the technique that Pasteur developed to detect traces of life in wine. Already when he was twenty, Pasteur bought him a name, proving the existence of molecules with a characteristic shape. In the meantime he added and proved that the shape of these molecules indicates the life in them. It was such a profound discovery that it is still a mystery to many, let us enter Pasteur's laboratory and listen to his words:

How to explain the fermentation of the wine in the barrel, the fermentation of the sour pulp, the acidification of the coagulated milk, the turning into rot of dead leaves and plants buried in the ground? I admit and confess that for a long time I was guided in my research work by the idea that in the laws of organization of living beings and in the hidden physiological processes that take place in them, the right-handedness or left-handedness of the structure of matter is of equal importance.

Right and left - this was the deep secret that Pasteur followed in the study of the phenomena of life. The world is full of things, whose right form is different from their left form. Compare a right extractor with a left extractor, a right cochlea with a left cochlea, and above all the left hand with the right hand. One hand is in the place of the other hand, but it is not possible to rotate the hands in such a way that the right hand can come in place of the left hand, and vice versa. Pasteur knew that the same was true of certain crystals. Their whiskers are arranged in such a way that there are right-handed and left-handed forms of the same crystals.

Pasteur made wooden models of such crystals (he had nimble hands, and he was also an excellent draftsman), and even studied these models a lot. Already at the beginning of his research, it occurred to him that right-handed and left-handed molecules certainly exist, and that what is true about the crystal surely reflects a property of the molecule itself. And this should be reflected in the behavior of the molecules in any asymmetric situation. If you dissolve such crystals and pass through the solution a polarized (that is, asymmetrical) light beam, then the molecules, which Pasteur called right-handed, will shift the plane of polarization of the light to the left. A solution of crystals, all of the same type, will behave asymmetrically towards an asymmetrical beam of light coming from a polarimeter. If the polarization disk rotates, the solution will look dark and light suits, and again dark and light.

The interesting thing is that a chemical solution of living cells behaves exactly the same way. We still do not know why living matter has this strange chemical property. However, the existence of this property proves that living matter has a typical chemical character, and that it has maintained this character throughout evolution. For the first time, Pasteur discovered the connection between all forms of life and a certain type of chemical structure. The inevitable conclusion from this is that there is a connection between the process of evolution and chemical processes.

The theory of evolution has ceased to be a battlefield. The data that speak for her are today more numerous and diverse than they were in the days of Wells and Darwin. The most interesting and newest evidence comes from the field of chemical processes carried out in our bodies. For example: I can move my hand right now because my muscles contain a supply of oxygen, which has been put there by a single protein called myoglobin. This protein consists of a little over one hundred and fifty amino acids. The number of amino acids is equal in his body and in the bodies of all other animals that consume myoglobin. But in the amino acids themselves there are slight differences. Between me and the chimpanzee there is a single difference in one of the amino acids. Between me and the African lemur of the galago genus (an inferior primate) there are differences in some amino acids. Between me and sheep or mice the differences are more numerous. The number of differences in the amino acids is the measure of the evolutionary distance between me and any other mammal.

Obviously, we must look for the cause of the evolutionary progress of life in the construction of certain chemical molecules, but this construction must begin from the materials that rested on the surface of the newborn earth. If we want to talk sensibly about the beginning of life, we must take a very realistic approach. We must ask a historical question. What did the surface of the earth look like and what was the nature of the atmosphere four thousand million years ago, before life began?

We know the answer in general terms. The atmosphere was emitted from the interior of the land, and it thus resembled a volcanic environment. It was a kind of cauldron of steam, nitrogen, methane, ammonia and other gases, plus a certain amount of carbon dioxide. One gas was missing in this atmosphere: it did not have any free oxygen. It is important to emphasize this. Oxygen was created by plants, and it did not exist in a free state before the existence of life on earth.

The gases and their compounds, which also slowly dissolved in the oceans, formed a recirculating atmosphere. How did this atmosphere react to the action of lightning, to electrical discharges, and especially to the action of ultraviolet light, which penetrated it without stopping, in the absence of oxygen. This question was answered by a beautiful experiment conducted by Stanley Miller in America, around 1950. Miller created such an atmosphere - a mixture of methane, ammonia, water, etc. - inside a glass container. For many days he boiled the mixture, passing through it electrical discharges, in imitation of lightning and other intense forces. And lo and behold, the mixture started to turn cloudy. And what was the reason for that? Miller examined the mixture and found that amino acids were formed in it. It was a decisive step forward, because amino acids are the building blocks of life. What are the proteins made of and every living thing is made of proteins.

Until a few years ago we used to think that life began in such hot, electric conditions. But lately it has occurred to some scientists that there are also extreme conditions of a different kind, whose action is no less vigorous. It is about cold and ice. Apparently this is a strange idea. But ice has two properties that encourage the formation of simple basic molecules. First of all, the freezing process concentrates the material, which at first must have been in a state of very dilute solution in the oceans. Secondly, the crystalline structure of the ice apparently allows the molecules to arrange themselves in a certain way, which must have been important in all stages of the development of life.

In connection with this, Leslie Orgel conducted some elegant experiments. I will describe here the simplest of them, he took some of those basic ingredients, which were certainly present in the ancient atmosphere: hydrogen cyanide, ammonia and more, dissolved them in water and froze the mixed solution for several days. By concentrating the material, a small iceberg was formed, and at the top of the mountain, a tiny colored spot testified that organic molecules were formed there. Of course these were amino acids. But the most important thing is that Orgel found that in this way he created one of the four basic elements of the genetic alphabet, which directs all life. He created adenine, one of the four bases of DNA. It is therefore possible that the alphabet of life contained in D.N.A. Formed in such cold conditions and not in tropical conditions.

The secret of the origin of life should not be sought in the complex molecules but in the simplest molecules capable of replicating themselves. The ability of the molecule to copy itself, to create copies in its own image, this is the feature that characterizes life. In connection with the problem of the origin of life, the main question is therefore whether it is possible that the basic molecules, identified by the biologists of our generation, were created by natural processes. We know what we are looking for at the beginning of life: simple basic molecules, such as the bases adenine, thymine, guanine and cytosine, the components of the spirals of DNA, which copy themselves each time the cell divides. The continuation of the process that created more and more complex organisms is another problem, a statistical problem, that is, a problem of the development of complexity by statistical processes.

It is natural to ask if molecules capable of copying themselves have been created many times and in many places. There is no sure answer to this question. We can only interpret the evidence provided by living things today, and draw conclusions from them. Today, life is governed by a few molecules, namely the four bases of DNA. They are the ones that transmit the transmitter of heredity in every living creature known to us, from the bacterium to the elephant, from the virus to the rose. The possible conclusion from the uniformity in the alphabet of life is that these are the only atomic arrangements capable of self-copying.

However, many biologists are not of this opinion. Most of them believe that nature has the power to invent other atomic arrangements, which are also capable of copying themselves, in their opinion the number of possibilities exceeds the four we know. If you are right, then it must be said that life is governed by the four bases of the DNA, because life began by chance precisely with them. According to this theory, the bases are evidence that life was created only once. After that, every time another atomic arrangement was created, it simply could not connect with the life forms that were already there. Nowadays there is certainly no one who thinks that life is still created out of nowhere on earth.

Biology was lucky and it discovered two ideas of fundamental importance within a period of one hundred years. The first was the theory of evolution by way of natural selection, founded by Wells and Darwin. And the second, the one discovered by biologists of our generation, is that the cycles of life can be expressed in chemical formulas and linked in this way with nature as a whole.

Shouldn't the chemical substances, which were present when life began, be seen as the exclusive property of the earth? In the past it was common to think so. Recently, however, evidence has been discovered that indicates a different situation. In the interstellar space, in recent years, spectral traces of molecules have been discovered, which never occurred to us that they could be formed in such cold regions, such as hydrogen cyanide, cyano-acetylene, formalaldehyde. These are molecules that have not been assumed to exist outside of Earth. In light of these discoveries, it is not impossible that life had many different origins and forms than we thought. And there is no need to think that if we ever discover life in one of the stars, we will find that it developed there in a way similar to that on Earth. It is even possible that we will not agree to see them as life forms and they will not be able to recognize us either.

* The chapter "The Ladder of Creation" is taken from the book: "The Man is Allowed" by Yaakov Bronovsky. The book was published in 1978 by Masada, translated by M. Warmbrand