Let's explore why evolution is not progress. Created by Sal Khan.
- [Instructor] Thought I would make a quick video to clarify some points on evolution, maybe clear up some points of ambiguity in some of my previous videos. So when you go to the Natural History Museum and you see these drawings where they start with a primitive ape and they show progressive species that show some form of progress, at least some form of progress when it comes to walking on two feet, you kind of and you know, it combinates with Homo sapien, sapien, us, you imagine that evolution is kind of this process that creates better and better things. You imagine that there's this notion of progress. That, as time goes on, each successive species is better than it's first. And I want to be very clear, that this notion of better really makes no sense in an evolutionary or natural selection context. That all that matters is fitness to your environment. Fitness to your environment or the frequency with which you're able to reproduce in an environment, which doesn't really match to our notion of better. So some people kind think oh well, what's going to be the next step in human evolution and they imagine you know, some human with a big brain that, you know, can move things with mental energy and all of that you know, and can see through things or whatever else. They imagine some kind of progress that look, we're more intelligent, we can do all of these things that an ape couldn't do. Maybe the next stage in evolution somehow will be some type of superhuman and I don't know what the next stage of evolution, if there is any next stage for human, you know, I can't go into that debate, but the idea is that that's not necessarily the case. Even if you take our current human population, success in evolutionary terms is very different than success in our, kind of, societal definition. For example, if you have someone, let's say you have two people. You know, this guy, some dude here, he's got a PhD. You know, he's got an MD. He's got a lot of money. I mean just you know, everything that society says is success but because he did his MD, PhD, he's been in school a long time and he decides not to have children or he wants to be very responsible, he looks at how many people there are in the world, and the overcrowding and the environmental impact. So let's say him and his wife, who is also an MD, PhD and has all this money and degrees and have spent a lot of their time in school. They decide to have one child. One child. Let me see, this is his wife, who has kind of similarly, she's similarly educated and from our point of view, this is a very successful, very responsible couple. Now let's say that there's someone, some other guy, over here, and he's just kind a, you know, let's say he's just nuts. From the get go, he was very irresponsible, he produced one child after another. Let's say by the time he's 30 years old, he has 10 children all with different mothers, maybe some of the children had to go up for adoption, who knows the situation with this guy's life, I don't want to be judgemental of it. But the general idea is that in society, we'll say, oh this guy is less successful. But from an evolutionary point of view, from an evolutionary point of view, this guy was far more successful. In fact people like this guy, the frequency of their genes, is increasing much faster than the frequency of these people's genes. So when we talk about fitness, from an evolutionary point of view, it's not necessarily fitness from the point of view that we like to think of it, in our regular kind of, value system that we have in society. These people looked very fit, intellectually and who knows maybe physically as well, but they weren't reproducing. Their genes aren't being passed on with the frequency of these guy's. I forgot the statistic but there's something like 80% of people in Asia have genes from one, or some, either one man or some small collection of men who date, actually I think it's from one man from the 1200s and it's either probably one of the Mongol warriors or you know, whether it's Genghis or Kublai Khan but it just shows you that there's some very, you know, and I'm not going to make any judgements here, but you could have very kind of, aggressive people who may have raped and pillaged you know, whole societies and they were very successful from an evolutionary point of view even though we might think that their actions are despicable. So I wanna give you the sense that there's, there's not necessarily this sense of progress. I mean if this, if this pattern I described, keeps happening, then this type of person will become less and less frequent in the gene pool and this person will become more and more frequent in the gene pool. So we might end up with a, eventually, a more aggressive human population or a less quote on quote, responsible one. So I wanna make that one clarification that evolution, evolution or natural selection is not just a, a series of progressive steps where we'll slowly and slowly become, or any organism becomes kind of a better and more intelligent, and faster animal. It just depends on it's environment and what's being selected for.