The role of natural selection in biological evolution is described systematically reflecting modern biological concepts. A new approach, based on the ideas regarding the physical phenomenon of percolation, was suggested and developed to generalize the theoretical and mathematical description of this key problem of biology. The natural selection of optimal variants in the evolutionary mutation flow is considered a percolation filter as a physical tool constituting the selection mechanism. The model is based on the concept of self-organization in hierarchical structures of speciation where the trigger properties of the cell (node), like a valve, define the deterministic component of new mutations fixation and the drift defines the collective behavior of the percolation lattice nodes and connections (mutations) that introduces an element of randomness to the process of new mutations fixation in mutation streams. As a result, considering various values of the selection and drift coefficients, as well as the ratio of prohibiting and permitting mutations, the modes of mutations fixation in generations were obtained at the population level.
$^1$Department of Biophysics, Faculty of physics, Lomonosov Moscow State University