[HarHarVeryFunny]

As long as all offspring aren't 100% exact clones of the parents then you'll get evolution.

In practical terms it would be impossible to genetically engineer away genetic variation (assuming you could convince people to stop having sex and visit your cloning lab instead). There are all sorts of things like DNA damage, horizontal gene transfer, and just the inherent error potential of reproduction that you would never be able to eliminate.

Of course it would also be highly undesirable to stop genetic variation, since that's what gives a species the ability to adapt and survive.

[seanmcdirmid]

You’ll get mutations, not evolution. You still need natural selection to sort out the mutations which gives us evolution, and that’s a bit harder now that we don’t have to worry about being hunted down by tigers.

Anyone can reproduce and pass down their genes, so what mutations are we currently selecting? Maybe looks, but I doubt even that.

[HarHarVeryFunny]

I'm sure if you looked at fertility rates across the globe, broken down by location/race/religion and other demographics, you'd find plenty of differences - some very large.

Yes, ability to fend off (or avoid) a tiger attack is not much of a factor nowadays, but even something as simple as a religion that encourages having large families, and encourages marrying within religion (you don't need to live on an island to be somewhat genetically isolated) will have an effect.

As far as survival (not dying) goes, I'm guessing that risk appetite, and certain specific forms of it (e.g. fear of heights) has a genetic component, and it looks like base jumpers and free soloists are experiencing selection pressure!

In the modern world there is also a lot of truth to the premise of the nominally satirical movie "idiocracy", where it's not things we regard as positive (strength, intelligence, etc) that drive reproductive success, but in fact the opposite, with birth rates among the unintelligent often higher than that among the intelligent (who are prone to worrying about having kids).

What tends to drive evolution the most seems to be occasional rapid shifts in the environment rather than stable selection pressures. For example, we were lucky that COVID-19 wasn't worse than it was, but nonetheless by definition those who died were those with immune systems less well prepared for the new threat, and the human species as a whole has now slightly "evolved" to be better able to survive that selection pressure.

[saltcured]

You're saying that as if survival doesn't remain an evolutionary pressure. Life is inherently demanding, and many mutations are lethal.

So, at best, the argument seems to be that the surviving gene pool may get more complex with lots of optional mutations which all coexist? Could we end up like some plant species full of cultivars where larger swathes of genes are expressing differently out of a very convoluted library?

If you're envisioning medical science to allow people to survive with otherwise lethal mutations, I would say that is not an escape from evolution. Instead, you've revised the reproductive cycle to include more epigenetic components. The species is still the survivable set of genes and cultural practices which are evolving together, and which terminate when they no longer function as a system.

[ninthcat]

Evolution happens even without any selection pressures, for example with genetic drift.

[seanmcdirmid]

That requires isolated populations and we don’t really have that anymore.

[HarHarVeryFunny]

Global travel has no doubt caused the gene pool to become more homogenous, but yet there are still clear differences between people from many parts of the world.

Isolation (really meaning tendency not to inter-breed) doesn't have to be physical - it can be cultural too, and it seems this isn't limited to humans - many animal species that are on the cusp of speciation (lions/tigers, horses/donkeys, etc) share the same habitat and are just choosing to avoid each other.

In any case, "isolated" populations are only necessary for speciation, not for evolution. Even a single drifting gene pool is going to evolve to adapt to the changing environment, since individuals will still differ genetically. Whatever the environment throws at you will cause some individuals to do better than others (e.g. you survived the Ebola outbreak, others didn't), and these fitter genetics will then spread in the gene pool.