Abstract
In the whole Universe it is possible to find organic complex substances known with the generic name of tholins. These substances are obtained by irradiation of several gas mixtures (excluding the O2). The analysis of the tholins indicates that they can release important bio organics present in proteins, nucleic-acid bases and so on. It has been proposed that the tholins could play an important role in the appearance of life on the Earth. The Chemical Evolution Theory parts from this type of substances to explain as the first living organism could arise.