Self-organized critical model of biological evolution

A punctuated equilibrium model of biological evolution with relative fitness between different species being the fundamental driving force of evolution is introduced. Mutation is modeled as a fitness updating cellular automation process where the change in fitness after mutation follows a Gaussian distribution with mean x> 0 and standard deviation σ. Scaling behaviors are observed in our numerical simulation, indicating that the model is self-organized critical. Besides, the numerical experiment suggests that models with different x and σ belongs to the same universality class.