What is the core of Darwin's theory of natural selection

What is the core of Darwin's theory of natural selection

1. Overproduction
2. Survival struggle (also called survival competition)
3. Heredity and variation (the power and basis of biological evolution)
4. The fittest survive
In fact, the survival of the fittest, the elimination of the fittest, natural selection theory leads to biological evolution
This is the second biology of junior high school!

As shown in the picture, zebras live in the savanna. Darwin's theory of natural selection is used to analyze and explain the evolutionary process of zebras. (1) there are individuals with different body colors in the zebra group, which indicates that the organisms have different characteristics______ This kind of characteristic is generally______ Yes______ (2) with the continuous change of the environment, zebras with black and white body color and fast running speed adapt to the environment and are not easy to be found by enemies______ In this way, the environment has a great influence on zebras______ And this effect is______ Yes, it determines the nature of biological evolution______ (3) the above-mentioned process shows that the motive force of natural selection is______ The result of natural selection is______ ．

(1) (2) Darwin believed that the excessive reproduction of living things causes the struggle for survival, which includes the struggle between living things and inorganic environment, the struggle within living things, such as the struggle for food, mate and habitat, and the struggle among living things. In the struggle for survival, individuals with favorable variation are easy to survive

Darwin's theory of natural selection thinks that biological variation is due to genetic variation or natural selection

Heredity and variation are the internal causes of evolution, and natural selection determines the direction of biological evolution