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Dr. Michio Kaku is the co-founder of string field theory, and is one of the most widely recognized scientists in the world today. He has written 4 New York Times[…]

There are no more evolutionary pressures driving gross human evolution, but that doesn’t mean we won’t be able to genetically re-engineer ourselves in the future.

Question: Have human beings stopped evolving? Will humans look any different in the future? (Submitted by Kiran Uttarkar)

Michio Kaku: Kiran, if you read science fiction you might think that humans in the future will be slender, short, bald, with big heads and big eyes that sort of the stereotype that you get from the comic books. However, you have to realize that as far a gross evolutionary pressure is concerned; there is none anymore on the human race. For example, in the old days, when we lived in the forests, there was enormous selection and pressures placed on us to develop a large brain, to understand how to use tools, to run, to be able to navigate, to survive in the forests. Enormous pressures on us because if you were not fit to live in the forest, you died. And so your genes are not here today.

But how much evolutionary pressure is being placed on us today? Well, first of all, there are no more Australias. Australia is a content that broke off from the other continents and it evolved very rapidly because it diverged from the rest of the evolutionary tree. There are no more Australias anymore.

In the sense, we have jet airplanes. You can jet airplane… you can go pretty much anywhere on the planet earth, meet people, have children and your genes are now spread throughout the planet earth. We no longer have any isolated pockets, like Australia, which would accelerate human evolution. Now, evolution is still taking place, it takes place every time two people mate. It takes place inside our bodies, in our immune systems, in our body chemistry. Evolution is still taking place. But gross evolution, that is, evolution that will give us big brains, big eyes, bald heads and little bodies, that kind of gross evolution is pretty much gone.

Now, that doesn’t mean that we can’t have genetic engineering. That’s many decades away. At the present time, we can only manipulate perhaps one gene at a time. It is a very painful process, we cannot, for example, create a pig with wings, that would require thousands of genes being manipulated. And we simply don’t have that technology. We only manipulate one gene at a time.

So I think we are many, many decades away from being able to actually influence human evolution. So in other words, chances are, decades from now, we’ll look pretty much the same.