The Damage Spreading Model Base On Bak-sneppen Model

In the basis of Bak-Sneppen model and Generalized Bak-Sneppen model,we study the evolution of biology.This paper discusses the self-organized criticality in the evolution model and the influence of damage in evolution model.In 1993,Bak and Sneppen introduced a simple model(Bak-Sneppen Model)to describe the biological evolution of interacting species of an ecology.The fundamental driving mechanism for the model is that species interact with each other,and the theoretical basis is that species with the minimal fitness value is more likely to mutate during the next time period.Because of the interactions among species,this mutation will affect the nearby neighbors,and the entire ecosystem will evolve together.Based on Bak-Sneppen model,Wei Li introduced the interaction factorα,and proposed a generalized Bak-Sneppen model.Interaction strength,denoted byα,is proposed to prescribe the degree of interaction among species.In the chapter one,the definition and the background of the self-organized criticality are introduced.Two properties of the self-organized criticality:fraction and 1/f noise are presented.Four models of the self-organized criticality are presented too.In chapter two,two properties of Bak-Sneppen model:the self-organized criticality and punctuated equilibrium are introduced.The influences of damage under two extreme conditions are presented.In chapter three,Damage spreading technique is used to study the influence of damage in a generalized Bak-Sneppen model.The interaction betweenαand the Hamming distance is given.New studies are used to discuss the issues in this paper,the results make people understand the influence of damage from different aspects.The Hamming distance is used to measure the short-time dynamics of Generalized Bak-Sneppen model.