Complex Systems Biology: 　　　　　Universal Statistics, Biological Plasticity, and Evolution 　　　　　We intend to understand life as a `complex system', by unveiling 　　　　　universal features underlying all biological systems. For this purpose, 　　　　　we take a constructive approach, by setting up a simple system both 　　　　　experimentally and theoretically, and answer general questions on a 　　　　　biological system. After surveying this standpoint, I discuss some of 　　　　　recent studies along this line, both in theory and experiment. 　　　　　First, I discuss universal statistical laws of chemical abundances in a 　　　　　cell that sustains recursive production. From theoretical studies of 　　　　　simple protocell models, discovered are a power law law in average gene 　　　　　expression and log-normal distribution of the abundances of each 　　　　　chemical. Experimental verification of these laws is also presented. 　　　　　Second, to discuss relevance of this phenotypic fluctuations to 　　　　　evolution, we extend fluctuation-dissipation theorem in physics, to obtain 　　　　　universal relationship between phenotypic and genetic fluctuations. 　　　　　Proportionality between evolution speed and 　　　　　phenotypic fluctuation is derived, as is demonstrated experimentally. 　　　　　The next problem we address concerns with search for some chemicals 　　　　　that suppress the above fluctuations. Taking a simple reaction network 　　　　　model, we show that molecules minority in number are preserved well 　　　　　by suppressing the fluctuations. These molecules control the behavior 　　　　　of a cell relatively strongly, and start to play the role of genetic 　　　　　information. Origin of heredity and evolvability are discussed, 　　　　　based on this minority controlled state. 　　　　　Last, if time is allowed, I will briefly explain how differentiation 　　　　　of cells and robust development are a natiral consequence of 　　　　　coupled dynamical systems.