There are many opinions, hypotheses and theories about the origin of life on earth.First there was a theological theory.Her representatives believe that life - the result of divine providence.Despite the fact that the theory has appeared in ancient times, it is actively developed and today, especially in church schools.Modern theological anthropology due to constant discoveries aimed at explaining scientific facts.The theory has not been proved, nor disproved.Its disadvantage is that it is not scientific, and can not be examined through experiments.
emergence of life on earth is justified as the theory of panspermia.Her supporters hypothesized extragalactic origin.Representatives are - G. Richter, Lazarev, Helmholtz and others.For Gemgolts he believed that bacterial spores and other organisms have been brought to Earth with meteorites.Through laboratory tests it was found that living organisms are resistant to low temperatures and other adverse effects.Even prolonged exposure of plant seeds and spores in liquid nitrogen or oxygen does not lead to their death.There is a point of view that life has been brought intentionally or accidentally space aliens.There is an opinion that in the dust and gas clouds of outer space is the micro-organisms.They captured comets and using last fall on the planet.
There are other theories of the origin of life on earth.For example, the steady state of the Earth.Her representatives believe that life has existed forever.Forms also have always existed and will never occur.There is only a change in their population, or particular kind of dying out completely.Supporters do not recognize the possibility of the existence of transitional forms.In support of their position they result Crossopterygii fish - coelacanth, long considered a form of transition from fish to amphibians.However, in 1939, he was caught the first instance of this fish, and then the next.This proved that the coelacanth - not a transitional form.There were other examples of detection of living organisms thought to be extinct.
emergence of life on earth is justified and evolutionary theory.The representatives believe that the universe was formed about 15 billion years ago because of the Big Bang.After a galaxy at high speed steel removed from each other.As a result of the planet under the influence of chemical and electrical reactions in the atmosphere and the water formed organic compounds, then life began and the process of evolution of living matter.
According to biochemical theory of Oparin, the emergence of life on Earth is seen as a result of the evolutionary development of matter.The simplest organic compounds emerged from the primary gas atmosphere.As a result abiotic synthesis of organic compounds formed chain of proteins and nucleic acids.Subsequently fazoobosoblennye formed of organic substances, which have been separated from the membrane environment.Then there was the emergence of simple cells that have the properties of the living, and the subsequent evolution.L.Millera During experiments it was proved that the amino acids and other organic molecules may be formed from inorganic compounds under ultraviolet light and electric discharges.
Modern hypothesis of life on the ground is different, but the prevailing hypothesis is that RNA world.Supporters believe that during the chemical evolution was an intermediate step that some RNA molecules multiplied and compete.As a result, studies have found that certain RNA molecules may replicate without complex protein molecules.
