Conclusion: The inferior variation is easy to be eliminated, the superior variation is easy to survive and leave to the offspring.

(2)The Principle of Biological Survival Struggle.

Fact 1: Survival resources are limited;

Fact 2: Biological fertility is excessive;

Conclusion: Most of the offspring of living things must perish.

The two facts here are both minor premises, the major premise is that living things must perish when they do not have enough resources to survive. By perish, I mean the inability to reproduce. Overreproduction makes the survival of organisms very competitive, the rate of death is very high, so that only a few of the most superior organisms can survive. The result of the combination of survival struggle and natural selection is biological evolution, that is, the conclusion of the principle of natural selection is the major premise, the principle of survival struggle is the minor premise, and the following biological evolution principle is concluded.

(3)The Principle of Biological Evolution:

Major premise: The inferior variation is easy to be eliminated, and the superior variation is easy to survive and leave to the offspring.

Minor premise: The vast majority of the offspring of organisms must perish;

Conclusion: The inferior variations of organisms must be gradually eliminated, and the superior variations can survive and be left to the offspring.

The so-called biological elimination refers to the complete extinction of a certain structure of organisms. Survival and elimination are directly related to the number of organisms, not directly related to the reproduction rate and death rate. When an organism mutates, it directly affects the rate of reproduction or death, not the number of organisms. When the rate of reproduction is less than the rate of death, organisms may survive for a long time, but if this speed difference is maintained, organisms will inevitably become extinct. Therefore, natural selection of organisms must be linked to the rate of reproduction and death.

The phenomenon that the rate of reproduction is greater than the rate of death cannot be maintained for a long time, the number of any organism is bound to be limited by the environment. When the time is long enough, the average rate of reproduction of organisms must be equal to the rate of death.