The present view of biological phenomena is based on a biomolecular paradigm that development of living organisms is entirely defined by information stored in a molecular form as some genetic code. However, new facts and discoveries indicate that biological phenomena cannot be reduced to a biomolecular realm alone, but are also governed by mechanisms of other nature. These mechanisms, acting in tight cooperation with biochemical mechanisms, define life cycles of individual organisms, and, through this, the origin and evolution of the living world. Here, we present such a physical mechanism (General growth law), which represents a new physical law of nature. It acts at cellular, organ, system and whole organism scale levels, directing growth and reproduction together with biomolecular mechanisms by imposing uniquely defined constraints on distribution of nutrients between biomass production and maintenance, thus defining the composition of biochemical reactions, their change and irreversibility during the organismal life cycle. Mathematically, this law is represented by the growth equation. Using this equation, we introduce growth models and explain division mechanisms for unicellular organisms. High adequacy of obtained results to experiments proves validity of the General growth law and of the new physical paradigm of Life based on this law.