> 2. Given the process of natural selection, in another 200,000 years we will have been replaced by something different than us -- not necessarily bigger or smaller, smarter or dumber, just different.

In the very, very long run, who knows.

But int the timescale of tens or even hundreds of thousands of years I don't think there will be any natural selection process that will apply to the current status of humanity as a species, unless for some reason civilization will fall and humans are scattered throughout the globe.

We've pretty much stopped evolving as a species through natural selection events. There's not much of that happening in the homogenized urban setting where the majority of people live, and will live for the foreseeable future.

Actually, having the current civilization as a substrate for the species does change the playing field considerably from what it was a few thousand years ago.

As for biodiversity creating some sort of 'better adapted species' to take over our position - the sad truth is that biodiversity is in rapid decline, and I don't know when it will stop. We are not killing the planet per se, only... homogenizing it and making it fit for humans.

In a million years, sure, who knows what will happen. But in the current mass extinction event - if we can feed the the human species it's very difficult for me to imagine anything will replace us when the timescale is only the current estimated age of the species.

Prepare to be rickrolled for the next 100k years. Or maybe we will move into some dense compute substrate made of exotic materials.