The Likely and Unlikely Paths of Evolution

One of the inherent characteristics of biology is that unlike other sciences there are no apparent laws. For example physics cannot do without the law of gravitation. In chemistry we have the law of chemical equilibrium which involves Le Châtelier''s principle. However Biology at least for the time being does not have them. Even so if there is one phenomenon that has occurred in all living beings it is the fact that they have evolved. Who knows maybe as a result of this observation there is a law of biology that no biologist or other scholar has yet realised?