There are many views, hypotheses and theories about the emergence of life on earth. Theological theory came first . Its representatives believe that life is the result of divine providence. Despite the fact that the theory appeared in ancient times, it is actively developed today, especially in church educational institutions. Modern theological anthropology in connection with constant discoveries is aimed at explaining scientific facts. Currently, the theory is not proven, but not refuted. Its disadvantage is that it is unscientific and cannot be investigated through experiments.
The emergence of life on earth is also justified by the theory of panspermia. Its supporters hypothesized extragalactic origin. Representatives are G. Richter, P. Lazarev, G. Helmholtz and others. So, Hemgoltz believed that the spores of bacteria and other organisms were brought with meteorites to the Earth. Using laboratory studies, it was found that living organisms are resistant to low temperatures and other adverse effects. Even prolonged aging of plant seeds and spores in liquid nitrogen or oxygen did not lead to their death. There is a point of view that life was introduced intentionally or accidentally by space aliens. There is also an opinion that there are microorganisms in the dust and gas clouds of outer space. They are captured by comets and with the help of the latter fall on the planet.
There are other theories of the origin of life on earth. For example, the stationary state of the Earth. Its representatives believe that life has existed forever. Species also existed always and never arose. Only a change in their numbers occurs, or a particular species completely dies out. Proponents do not recognize the possibility of transitional forms. In support of their position, they bring cysterae fish - coelacanth, which for a long time was considered a transitional form from fish to amphibians. However, in 1939 the first specimen of this fish was caught, and then the subsequent ones. This proved that coelacanth is not a transitional form. There were other examples of the discovery of extinct living organisms.
The emergence of life on earth is also substantiated by evolutionary theory. Representatives believe that the universe formed about 15 billion years ago due to the Big Bang. After the galaxy, they began to move away from each other at great speed. As a result, organic compounds formed in our atmosphere under the influence of chemical and electrical reactions in the atmosphere and water , then life began and the process of evolution of living matter began.
According to the biochemical theory of Oparin A., the emergence of life on earth is considered as the result of the evolutionary development of matter. The simplest organic substances originated from the gases of the primary atmosphere. As a result of abiogenic synthesis of organic compounds, chains of proteins and nucleic acids formed. Subsequently, phase-separated systems of organic substances were formed, which were separated by membranes from the external environment. Then came the appearance of the simplest cells that possessed the properties of living things, and subsequent evolution. During the experiments of L. Miller, it was proved that amino acids and other organic molecules can be formed from inorganic components under the influence of ultraviolet radiation and electric discharges.
Modern hypotheses of the origin of life on earth are different, however, the hypothesis of the RNA world is predominant. Proponents believe that during chemical evolution there was an intermediate stage when individual RNA molecules multiplied and competed. As a result of studies, it was found that individual RNA molecules can self-reproduce without complex protein molecules.