The natural biological community not disturbed by human is the only means to maintain the local and global environment adaptable for living activities.The stability of the global climate is just based on the adjusting function of the natural biological community which is determined by genome of the composite species.Developing and transforming the community by man may lead to the chromosome distortion and gene deficiency.Once the disturbance toward the community ceases,the biological community will restore the environment to a state adaptable for its existence.