Time is directional and always flows from the past to the future. This is the arrow of time. In the process of biological evolution, the past of time and the future are asymmetric, which is an irreversible process. But the time arrow of biological evolution and Entropy increase is different. Entropy increase means degradation, that is, the decomposition and decline of old things; and evolution is the generation and development of new things, and its time arrow points to the decrease of entropy. therefore. ['There is only one direction for the evolution of living things b.', 'The evolution of organisms can be divided into two categories: degradation and evolution.', 'Biological evolution took a short time in the past and a long time in the future.', 'Changes in entropy are non-directional.']