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Comment by badminton1 | Hacker News Reader

I wonder if this interesting property reduces their mutation rate (and therefore slows their evolution).

To be fair, what do they need to evolve for at this point? It's hard to imagine an extinction event, short of the sterilization of the planet or the end of Solar activity, for them.

Water bears shall inherit the Earth.

They already have. :)

As a somewhat unrelated aside, I think that if we bite the big one as a species, Waschbär (raccoons) might inherit the Earth. They have that combination of clever "hands", social structures, omnivorous diets that could make it work for them. Still, beneath it all, the water bears will secretly rule, through freeze and thaw.

So if the warning is "beware of the Sea People"[0], maybe we really should be wary of the water bears?

[0] - https://news.ycombinator.com/item?id=12767821

This is how the world ends. Not with a bang, but a water bear.

More so than apes though?

Apes are too restricted in their habitats compared to something like a racoon, and anything which takes us out, is likely to do the same for them... even assuming they survive our influence on their environment over the next few decades. Raccoons meanwhile, have adapted to us.

Good point. I've given this issue a lot of thought for some reason.

I had crows and elephants on my list. But raccoons actually make a lot of sense.

Crows are amazing creatures, but they lack the advantage of hands, and I think that really matters in the long run. If something is going to take our place, they probably need to be adept tool users, so the same issue is there for Elephants, plus they lack the ability to rapidly adapt to new environments and food sources. Maybe Octopodes will make a surprise "come from underwater" victory though, who knows?

I'm glad that I'm not the only one who thinks about this kind of thing by the way.

I figured crows feet would evolve to be hand like but that would take a while.

I believe elephants can manipulate the ends of their trunk like fingers plus having tusks to hold things against.

In any case I'm putting my money on racoons now.

Good point about Elephants, I didn't consider that. Thanks for the enjoyable and informative exchange.

I would say their ability to resist extreme conditions might not be the same as resisting change in general. e.g: absence of food. Tardigrades are known to eat each other and in the absence of food they would probably resort to cannibalism.

They eat bacteria. The one thing that one can count on outsurviving tardigrades is bacteria.

If your follow on question is, "and I wonder what happens if you transcribe that gene into higher plants and animals" then the answer to that question becomes quite interesting.

I suspect that we're going to live to find out the answer.

I don't think that mutation rate correlates with evolution speed. Of course, never having mutations altogether would, but if you have some mutations they'll be more than enough given the time frame.

The first thing you learn when playing with genetic algorithms is that the mutation rate has a major influence on the outcome. Evolution doesn't work if the rate is too high or too low and within the working range it also shows a positive correlation between mutation rate and speed of evolution. It makes sense that the evolution of Tardigrades has slowed down tremendously by now.

As far as overall survivability for an animal is concerned, regardless of the mutation rate, one would be a little hard-pressed to imagine how they'd climb any further up whatever hill on the fitness landscape it is they're on.

Again just no. Tardigrades are predated by each other and plenty of other animals. Just because you can survive drought and radiation doesnt mean you can mechanically survive another organism evolved to eat you hunting you down.

No it doesn't make sense at all. The vast majority of natural evolution works through composability and shuffling of already evolved structures. So through sexual recombination. Many tardigrades can also selectively vegetatively reproduce fixating any mutation in the population. This means the rate of evolution has no reason to slow at all. It could even be quite fast as beneficial mutations have a mechanism to become widespread in the population straight away, unlike many other animals. Even more interesting is the level of possible horizontal gene transfer seen in the Tardigrade genome. So there is plenty of injection from other lineages to keep up diversity. If you want the genetic algorithms perspective on how that works check out Richard Watson's work https://mitpress.mit.edu/books/compositional-evolution But in general it's really quite foolish to imagine because you know something about GAs you have even a hint of what natural evolution is like. The two are very different. GAs are super simplistic and essentially only cover some basic concepts from 100yol evolutionary theory and mostly ignore essentially everything we know from modern molecular biology. Island GAs and Richard Watson's concepts of compositional evolution actually capture a lot of what happens. The reason is fairly simple if you put it in context of how molecular structures evolve, a good starting place is knowing what a protein domain is https://en.wikipedia.org/wiki/Protein_domain

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