Do you know how life arose on Earth? If not — do not worry, scientists — people trained to search for answers to various questions themselves are still undecided on this. But there are a lot of theories — and outdated (the issue is something very interesting, and always occupied the minds of the people) and the newest. Let's see and evaluate.
The most important theory of the origin of life can perhaps be called the theory of the stationary state. Following this hypothesis, the Earth has existed forever, ever arising, has always been able to support life, and any changes to it were quite small. Species of living organisms and have always existed and have any kind have only two options — to change the size or extinction. It is clear that this "theory" is now simply does not hold water.
Another theory is old, and still widespread in China, Egypt and Babylon — the theory of spontaneous generation. Empedocles' doctrine of organic evolution — one of her interpretations. Aristotle also adhered to this view. The point of it is that certain particles of matter are in themselves "active principle" that can, under appropriate conditions to create a living organism. This is the "beginning", according to Aristotle, can be found in the fertilized egg, rotting meat, mud and sunshine.
Along with the spread of Christianity, especially in the Middle Ages, the Church condemned such views. They were considered an attribute of magic and manifestation of diabolism, however, as befits a respectable theory, it continued to exist. Moreover, the supporters of this view have been experimenting.
At various times since the sixteenth century thinkers tried to make a living out of different ingredients. The results were at times very funny: it will turn the mouse from the laundry and wheat in a dark closet, then a more rigorous experiment in closed vessels does nothing but open — "samozarodyatsya" maggots.
Possible ingredients for life, even boiled, but only made sure that the heat was killing all life. Finally, the theory was defeated by Louis Pasteur, who proved the validity of the theory of biogenesis, that is, the origin of life from a previous life. However, this caused a baffling question of the origin of the first living organism.
It is equally common among men of science at the time was the theory of creationism. According to her, life is the result of a supernatural event in the past, that often means a divine creation. Back in 1650 the Irish Bishop Usher has calculated that the Earth is in October 4004 BC And this is just one option of many such calculations.
Another theory with unknown name — the theory of panspermia. The system looks for granted considering the postulate of an extraterrestrial origin of life. Argues that life could arise repeatedly at different times and in different places of the universe. The reason for these findings was the discovery of meteoritic materials that were found substances — predecessors of living, as well as the structure, similar to the simplest organisms.
The most promising scientists believe the theory of evolution or biochemical coacervate drops. Simplistic sense of it is that, under certain conditions, which are likely to have existed on the planet, organic matter could be created much easier and can be stored without undergoing decay for a long time. The variety is in the oceans simple connections and large time scales suggest the possibility of accumulation in the ocean a lot of organic matter, formed the "primordial soup" that could harbor life. A number of experiments carried out in the middle of the last century has confirmed the reality of some postulates of the theory, however, the main issue — the mechanism of the transition from non-living to the living — the theory leaves open.
In recent years, more and more support is the theory of RNA — a world becoming dominant in this matter. The gist of it is that the founders were not life proteins and RNA molecules. Education components of the RNA did not represent fundamental difficulties. Under certain conditions, as a result of complex chemical processes and a semblance of natural selection could be formed the first cell.
With the development of spectroscopic methods of space exploration, the acquisition of new interesting facts that speak in favor of the possibility of life beyond Earth and entering it in the future for our planet meteor or other transport.
Previously, it has been found that many meteorites contain a variety of chemical substances suitable precursors life. Despite the fact that the biological past of these inclusions is not yet confirmed, the theory of biological origin is booming, continues to receive all new information about the discovery of similar structures in meteorites found, particularly in the lower layers of the continental ice sheet of Antarctica.
But, as they say in jest scientists themselves, no matter what the theory has not adhered to the man of science, as if he fiercely defended his views in a dispute with the opponents, he secretly still believe that life on Earth came at the behest of God on the fifth day of creation .