Biological variation is the fundamental driving force of biological evolution. If there is no variation, it can be said that there is no evolution. The types of biological variation include gene mutation and chromosome variation. But the probability is very small, only one in ten thousand or even less. General variation is harmful, and beneficial variation adapts to the living environment. Hereditary beneficial variation can be continuously passed on to future generations, so that organisms can constantly adapt to the new environment in which they live, and their vitality will be more tenacious and will not be eliminated.