Through research, it is found that these changes are inherited through the father's sperm, that is, if the prospective father goes hungry, children and grandchildren are more likely to gain weight.
This is not alarmism, it is scientific common sense, that is, "heritable variation" in evolution.
We know that many characteristics of living things can be stably passed down from generation to generation, and they can also change in the process, which is heritable variation.
Darwin believed that genetic variation originated from the germ cells of organisms. French naturalist Lamarck believes that heritable variation comes from the whole body of an organism, which is then collected into sperm or eggs and passed on to future generations.
Today, we know that Darwin was right. The experience gained cannot be inherited, but only the variation carried in germ cells can.
But then a great event happened, which revived Lamarck's theory.
1944, in order to suppress the Dutch resistance movement, the Nazi army cut off the food supply throughout the Netherlands, causing millions of Dutch people to fall into famine. The great famine lasted until the spring of 1945, causing tens of thousands of deaths.
The famine had terrible long-term effects. Decades later, it was found that those children born in famine grew up in poor health, and many people suffered from metabolic diseases such as obesity, diabetes and cardiovascular diseases. Moreover, the descendants of these children, that is, the third generation, also continued these diseases, and they lived in an era far from the famine era.
These changes are passed down through the father's sperm, that is to say, if the prospective father goes hungry, then the children and grandchildren are more likely to gain weight.
Suppose a man often goes hungry when he and his wife are preparing to have children. According to Darwin's theory, this matter is his own business, a big living vessel, and has nothing to do with the sperm in his body. But in fact, sperm is indeed affected. After all, the energy needed for its maturation and division is indirectly provided by this man's body. So the chemical modification of DNA sequence in sperm has changed, and a specific gene has been turned on or off.
In the whole process of this sperm looking for an egg to combine with it and give birth to a new life, the DNA carried by the sperm has been copied and spread hundreds of millions of times, and these chemical modification changes have also been preserved in every cell of the child, including the next generation of sperm in the body. In this way, his children, children's children, all carry the memory of the "great famine" in their bodies, which has a corresponding impact. These influences will be passed down from generation to generation for a long time until these "memories" are "erased" by the life experiences of future generations.
Darwin's theory and Lamarck's theory can coexist. On the one hand, heritable variation is realized by changing the DNA sequence of germ cells, which has little to do with the life of parents. Darwin was right. On the other hand, Lamarck reminds us that parents' major life experiences, such as famine or other indelible fears and injuries, will also affect sperm and eggs in some way, thus passing on some changes to the next generation or even generations. In some cases, Lamarck's theory is also correct.
This knowledge that we can understand and accept is closely related to our life. The knowledge we can understand and accept comes from Wang Liming's lecture on Wang Liming's theory of evolution.
This book, which can be read by ordinary people, can give us a preliminary understanding of evolution and learn the enlightenment of the life world to human survival from many magical stories.
Take you to see the world from an evolutionary perspective.