Future evolution: from looks to brains and personality, how will humans change in the next 10,000 years?

8th March, 2022.      //   General Interest  // 

file-20220225-21-1ewvdn2Humanity is the unlikely result of 4 billion years of evolution.

From self-replicating molecules in Archean seas, to eyeless fish in the Cambrian deep, to mammals scurrying from dinosaurs in the dark, and then, finally, improbably, ourselves – evolution shaped us.

Organisms reproduced imperfectly. Mistakes made when copying genes sometimes made them better fit to their environments, so those genes tended to get passed on. More reproduction followed, and more mistakes, the process repeating over billions of generations. Finally, Homo sapiens appeared. But we aren’t the end of that story. Evolution won’t stop with us, and we might even be evolving faster than ever.

It’s hard to predict the future. The world will probably change in ways we can’t imagine. But we can make educated guesses. Paradoxically, the best way to predict the future is probably looking back at the past, and assuming past trends will continue going forward. This suggests some surprising things about our future.

We will likely live longer and become taller, as well as more lightly built. We’ll probably be less aggressive and more agreeable, but have smaller brains. A bit like a golden retriever, we’ll be friendly and jolly, but maybe not that interesting. At least, that’s one possible future. But to understand why I think that’s likely, we need to look at biology.

The end of natural selection?

Some scientists have argued that civilisation’s rise ended natural selection. It’s true that selective pressures that dominated in the past – predators, famine, plague, warfare – have mostly disappeared.

Starvation and famine were largely ended by high-yield crops, fertilisers and family planning. Violence and war are less common than ever, despite modern militaries with nuclear weapons, or maybe because of them. The lions, wolves and sabertoothed cats that hunted us in the dark are endangered or extinct. Plagues that killed millions – smallpox, Black Death, cholera – were tamed by vaccines, antibiotics, clean water.

But evolution didn’t stop; other things just drive it now. Evolution isn’t so much about survival of the fittest as reproduction of the fittest. Even if nature is less likely to murder us, we still need to find partners and raise children, so sexual selection now plays a bigger role in our evolution.And if nature doesn’t control our evolution anymore, the unnatural environment we’ve created – culture, technology, cities – produces new selective pressures very unlike those we faced in the ice age. We’re poorly adapted to this modern world; it follows that we’ll have to adapt.

And that process has already started. As our diets changed to include grains and dairy, we evolved genes to help us digest starch and milk. When dense cities created conditions for disease to spread, mutations for disease resistance spread too. And for some reason, our brains have got smaller. Unnatural environments create unnatural selection.

To predict where this goes, we’ll look at our prehistory, studying trends over the past 6 million years of evolution. Some trends will continue, especially those that emerged in the past 10,000 years, after agriculture and civilisation were invented.

We’re also facing new selective pressures, such as reduced mortality. Studying the past doesn’t help here, but we can see how other species responded to similar pressures. Evolution in domestic animals may be especially relevant – arguably we’re becoming a kind of domesticated ape, but curiously, one domesticated by ourselves.

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