Emergence of life

Dr. Jerzy Grębosz from the Institute of Nuclear Physics PAS believes that the emergence of life on Earth was not an unique phenomenon in the universe. "The universe tends to generate more and more organized systems - even life. And life is probably common in the universe" - he said.

 

According to the scientist, humanity itself is not the purpose of existence of the universe. DNA mutations do not have any particular direction, and evolution does follow a predefined plan. "If we rewind evolution several hundred million years back and let it play out again, humans would probably not appear" - admitted the physicist.

 

According to the researcher, a common belief even half a century ago was that it was enough to know the initial conditions of the system and the mathematical formula, according to which phenomena in this system occur in order to be able to predict its future. It turned out, however, that thigh were not that simple. In nature, there are in fact chaotic systems, in which the time course could never be accurately predicted. According to Grębosz, chaos and associated unpredictability are an inherent properties of the universe. However, chaos - in addition to the unpredictability - has yet another amazing property: it can produce designs, patterns, structures. From this chaos spontaneously emerge patterns that change over time, forming even very complicated forms.

 

This was predicted by Alan Turing, who was trying to answer the question of whether there is a mathematical sense in nature. "The mathematician wondered, for example, how the zygote cells without any central control can begin to differentiate and self-organize" - described Dr. Grębosz. Turing demonstrated mathematically that it can be caused by undiscovered at the time oscillating chemical reactions. Coinciding reactions in space can lead to the formation of patterns that are unpredictable, but govern by certain rules. These patterns include spots on animal hair. Turing showed that although complex phenomena occur in the zygote, somewhere at the bottom they have a simple mathematical basis, said Dr. Grębosz.

 

Oscillatory reactions were later accidentally discovered by Boris Belousov, who observed a solution which periodically change colour with stirring: it would become blue or clear. "Belousov did not realize that he had discovered what Turing predicted. The same type of reaction is responsible for heartbeat" - said Dr. Grębosz. Indeed, it turned out that the oscillatory reactions create unpredictable, but in a way regular patterns (such as the well-known Belousov-Zhabotinsky reaction). This type of reaction thus shows that even a random mix of chemical compounds can spontaneously self-organize and create the pattern. "Self-organization in chemistry and biology occurs even on a very basic level" - added the physicist.

 

Mathematician Benoit Mandelbrot described the self-similarity and fractals. Using the then technical novelty, computer, he graphically showed that even a small system of equations may be sufficient to create an infinitely complex object. The secret of producing such a complex object "out of nothing" lies in the so-called feedback. In the Mandelbrot image, colour of a particular point is calculated by means of a string of numbers, this string has the property that it uses the previous element in the calculation of each next element. It turns out that this simple rule, repeated thousands of times, is sufficient to built complex systems.

 

"Well ... but the ever the most elaborate structures, patterns are not life. Indeed not, it is enough to allow even simple system to self-improve to achieve incredibly complex solutions" - admitted the scientist.

 

"Nature has an inherent property to produce patterns, but there is also a unique process that combines these patterns in a larger systems. This process is called evolution. It feeds on patterns and is capable of incredible work on systems. It turns simple structures into more and more complex, more perfect ones" - said Dr. Grębosz and noted an unfortunate drawback of evolution: it is difficult to carry out in the laboratory. These processes are very long and tedious - after all, evolution occurs on a cosmic time scale.

 

The researcher reminded that 3.5 billion years had passed since the origin of life on Earth. "If we treat this time as one year, and the present moment as midnight on Dec. 31, the time from January to the end of July would be the process of building a cell alone - says Grębosz. - Dinosaurs appeared on the 4th of December and died 20 days later. And humans? On one year scale, our distant ancestors, the australopithecines, appeared at 4 PM on Dec. 31. The last eight hours of the old year represent about 3.7 million years of human evolution" - he calculated.

 

What happened in the beginning of this hypothetical year? According to the physicist from Kraków, life (the process that led to the formation of the first cell) could begin in hot water pools around volcanoes. These conditions facilitated chemical reactions. This led to the formation of various chemical compounds, some of which lasted, some disintegrated forever. Then, a compound was formed that could, for example, consist of two bridged atom strands. "Sort of a short ladder with rungs" - described Grębosz. When the bridge cracked, strands would lose contact with each other. But they were able to self-organize - find necessary components in surrounding pool and recreate the disconnected strand. This, copies of the compound were being made, some accurate, some imperfect.

 

"This particular compound was differed from the others in that it could - in a sense - have children. When conditions in the pool were slowly changing, the compound was destroyed, but those imperfect copies remained, which could survive and proliferate in this new environment" - said the researcher. In time, the compound would become less susceptible to changes in the environment by forming a protective coating: the cell membrane. Making copies became more difficult, but the offspring hidden inside the cell molecules could better cope with adverse conditions. Over time, it became clear that cooperating identical cells had better chances of survival and generating offspring. Cells with the same ladder, the same DNA, the same recipe for creating more cells.

 

"This led to the formation of cell colonies, because in was easier to survive in a group. Over time, cells in colonies began to specialize. For example, some secured food, others digested it. Such a colony is no longer a simple colony. It is a multicellular organism. Increasingly complex multicellular organisms were forming, improved their survival mechanisms and transferred their genetic codes - said Grębosz. - We are here to transfer DNA to the next harbour. So actually, the purpose of life is to spread DNA" - he added.

 

"For the life to emerge, a central control designer is not required - believes the researcher. - For some people, this thought is very inconvenient, because it means that the Creator is unnecessary. They can always tell themselves that there is a more intelligent Creator, who created this whole simulation called the Universe, gave it the appropriate initial conditions, and then let it run. This is a loophole for those who want to believe in the Creator, make sense of it all" - said the scientist and added: "Life itself does not have a purpose. We are here to give it meaning".

 

PAP - Science and Scholarship in Poland, Ludwika Tomala