Chapter 25 unexpected caucasian

"Hello sir, I read your article about human default settings. You compare human beings just like that to a computer that can be restored to default settings - don't blame me, I think you are so It's too disrespectful to do. As human beings, we are better than computers after all, don't you think? I just said what I wanted to say, but I don't mean to ask you to apologize." Sitting across from me in the train The lady here recognized me, and I really wanted to argue with her angrily, telling her what "metaphor" and "humor" are.But I kept my posture, smiled, and tried to explain it in a friendly way with words like "don't just take it literally".It was obvious from the wrinkles on her face that she was about my age, maybe older, and people of our age need to be treated with kindness.

"Hmm..." I was about to speak when she interrupted me.Don't forget, this is a lady.She said: "At the end of that article, you asked a question: Why do Europeans have white skin? Then you went on to explain at length that human beings are essentially black. Are you going to write another article on this? I What I want to know is what you plan to write and when will you publish it. And..." Her words accompanied the train shuttle in the scenery outside the window, and the train would stop at the station from time to time, but she didn't, her words were like a waterfall Generally a thousand miles away.I found that she remembered exactly what I wrote.I saw her thinking about "what's going on" for a while, and complaining about my short-sightedness that surfaced from time to time, always talking about sex (so it seems that she also read other articles I wrote) After a while, she explained to me what I wrote like an elder. Fortunately, there were no other passengers in the carriage, but this also aroused a question: Why did she just sit opposite me? Isn’t there still so many empty seats? Are you reading it? As long as you read the "Don't get too close to me!", this problem can be solved.)

I took advantage of her panting and finally interrupted: "Look, there are still many uncertainties about white people..." "Okay, you continue." She interrupted me again.I said again: "But we feel more and more that what Darwin said makes sense..." Then, she began to ask questions like a first-class reporter, and we happened to be sitting in the first-class carriage. She said: "Let's start from scratch. You once wrote that humans lost their body hair two million years ago. At that time, people needed black skin to resist the sun. Is that thing called melanin? But what is a human being?" When did you become white?"

I said, "Because the colors don't linger in fossils, we can't say exactly when, but it's probably after humans left our cradle - Africa - tens of thousands of years ago. People headed north , away from the hot sun. Homo erectus started earlier, but their skin color is unknown. I am talking about Europeans here. For tens of thousands of years, humans have spread all over the world. Researchers have used various scientific techniques , have been searching for the exact date. But it is not important to our story, just know that humans set out to the less sunny areas." She said: "So, does it mean that melanin is no longer needed for protection?"

I said, "At least not 24 hours. The skin's mechanism of protecting the skin from the sun through pigment is still there, well, just look at those tanned people on the beach. But just because of the 'no need anymore', It's not enough to explain the disappearance of dark skin in evolution. A common theory, and I often tell my students, is that in the north, that is, in areas with less sunlight, black skin blocks too much sunlight. Leading to a problem - the body has a hard time making vitamin D, as the definition of 'vitamin', these elements are necessary for the normal functioning of the body, so white skin appeared in evolution. This will not hinder the absorption of sunlight , so that we have enough vitamin D. This idea has also been recently confirmed, the results of the study showed that black people living in Belgium are less able to produce vitamin D themselves."

She said, "That's right, thank you for your explanation. Will you write another article on this?" I said, "Oh wait, the story is just getting started. This is a very recent conclusion, and that's how science is, where the certainties are suddenly shaken, and that vitamin explanation is exaggerated. Black people in this regard The problem is not as big as people think, and there must be more than that. We still have to go back to Darwin, who proposed in his later works that the human race arose because of sexual selection." She said: "Are you talking about sex again? Why is it so serious all of a sudden!"

I said, "Sorry, it's not what you think! Sexual selection is a mechanism of evolution, just like natural selection, but with a different dynamic." She said: "I have learned something about natural selection. Different organisms are different in various aspects. Some can better adapt to the surrounding environment, and thus improve the chances of survival and reproduction. Good genes can be passed on, while others can adapt to the surrounding environment better. These genes spread through their descendants, and the species is quietly changing. Right?" I said, "That's right (applause)! But let me say that it's not just about 'species', it's about 'organization'. When natural selection exerts enough influence on a group of organs, organs will creep in." Change. Of course, in the system of natural selection, the surrounding environment is the driving force. Temperature, sunlight, food, water, parasites, etc., everything that may be present in the surrounding environment for hundreds of thousands of years determines the organ. The direction in which an organization—or species—changes. It is the opposite sex that dictates the direction in sexual selection. From the most basic point of view, it is actually the same, but the difference must still exist, through another method Come study."

She said, "Can you explain it a bit more? It's still kind of vague to me." I said, "Well... say the house finches, the males of this lovely little bird are distinctly different from the females. The males have a tuft of black feathers on their heads, necks and breasts, while the females have darker plumage. Single, not very noticeable. The size of the black area of ​​the male bird, that is, the number of black feathers, varies from bird to bird, some are more, and some are less. But one thing is certain, the female bird is more Prefers to pick a male with more black feathers to be the father of the chick, but it hasn't always been like this. Once upon a time, long ago, the male sparrows didn't have that black decoration, and the females had other criteria when choosing a mate , but what exactly it is is not clear. Among those birds, some males have darker plumage than others, and this does not attract the attention of sparrows. Blackbirds are everywhere in the living things A variant of that. However, unexpectedly, an important thing happened."