[sentientmachine]

Even then it would probably not end our species. Even if every country had nuclear weapons and simultaneously vaporized every square inch of land surface (very unlikely), there would be a few carnival cruises and people who escaped to underground bunkers to hold out for enough years to repopulate some place later. It would be 99% losses, but the tough ones would survive. It may take a few thousand years to get back to where we were, but the buried technology would be found, and we would quickly get back to this point, with a lot more genetic resistance to the radiation fallout.

[lutusp]

> Even then it would probably not end our species. Even if every country had nuclear weapons and simultaneously vaporized every square inch of land surface (very unlikely), there would be a few carnival cruises and people who escaped to underground bunkers to hold out for enough years to repopulate some place later.

This is very, very likely, and there's even concrete evidence, based on the fact that the human race was nearly wiped out 70,000 years ago, but recovered.

70,000 years ago a huge volcanic eruption with global consequences called the "Toba event" reduced the human population to somewhere between 3,000 - 10,000 people. We know this by analysis of our DNA, which carries a lot of information that can be used to assess our genetic history. That record shows that a severe genetic bottleneck took place 70,000 years ago, and geographic evidence shows a corresponding massive volcanic event thought to be responsible. More here:

http://en.wikipedia.org/wiki/Toba_catastrophe_theory

[9876543210]

The theory behind the Toba event is really interesting, and the wikipedia article does mention that a number of other species are implicated with similar apparent bottlenecks, but it seems curious that this event wouldn't have affected all living creatures universally.

Based on the description of the event, a 5-10 year volcanic winter, I'm trying to imagine how such a disaster might compare to the dinosaur's extinction scenario. Why would only some creatures suffer more devastating effects than others? Does this point to additional complexities in the chain of subsequent events in the post-eruption environment, such as species-specific plagues, and partitioned food-web collapses due to the loss of a keystone species?

Would plants and aquatic species expess such a bottleneck differently, when compared to primates and other apex predators?

[lutusp]

> ... but it seems curious that this event wouldn't have affected all living creatures universally.

That's easy to explain based on the fact that some species tolerate temperature change better than others. Remember that the Toba event took place just as an Ice Age was beginning, so there were multiple stressors, affecting many species. The survivors were those that (a) could take shelter against the sudden cold, and/or (b) were naturally more resistant to the cold.

A similar partition happened during the asteroid-initiated dinosaur extinction event 65 million years ago -- some species were better able to deal with the sudden cooling of the global climate. Like the little mammals, who could take shelter underground, and from which we eventually sprang.

> Would plants and aquatic species expess such a bottleneck differently ...

Yes. Some of them are able to tolerate freezing conditions that would kill most land animals. As just one example, there are species of frog that can freeze solid, then recover when things thaw out.

https://www.units.muohio.edu/cryolab/projects/woodfrogfreezi...