1493 world history initiated by species exchange.

1493, Columbus discovered America. The author believes that since then, the world has experienced a multi-level species exchange, which constitutes the lowest decisive factor in the development of modern world history.

One is the great exchange of species between animals and plants. The Spanish brought horses, wheat and other crops to the American continent, and also brought American tobacco, potatoes, corn, sweet potatoes and tomatoes to the old world. Great changes have taken place in both the New World and the Old World due to newly introduced species. Indians are adapted to fighting on horseback. The new crops have greatly promoted the yield of the land, and the population of China and Europe has also gathered and increased. In China, the author thinks that this leads to the Malthusian trap: environmental deterioration, frequent floods and droughts, hunger and poverty; In Europe, the author believes that this has provided sufficient personnel reserves for European foreign colonization.

The second is the big exchange of bacteria and viruses. It is mainly the spread of various viruses from the old world to the new world, including smallpox, malaria and yellow fever. The spread of these viruses led to the extinction of Indians; It also led to a huge demand for black slaves in Europe (blacks are relatively resistant to malaria).

The third is the exchange of population. Mainly a large number of African blacks and European whites immigrated to the United States. There are a large number of blacks, and white immigrants are mainly men. These conditions led to the mixing of many colonial races and the emergence of new human beings with relatively complex lineages.

Human economic activities, especially agricultural activities, use different plants in different regions and have different and far-reaching effects in different regions.

After reading the complete book, we not only have a deeper understanding of many commonly used foods, but also have a deeper understanding of how the material basis at the biological level affects human life.

The economic base determines the superstructure. Geographical conditions, biological conditions, and human production and lifestyle (economic activities)-these seem to be three obvious "levels of material basic conditions".