[HoneyBadger]

I think we can safely say we've gone off-topic...ooops.

The presence of the atomic bomb-as opposed to those types of "conventional" wars that were being fought before 1945-allows for complete non-survivability of all major forms of life on Earth. It's not the fact that it has probably saved hundreds of millions of lives-It may well have done so, and I'm glad that it was invented, personally. It still remains a singular non-survivable technology if used to it's full potential. Biological weapons would most likely not affect all species, they might wipe out humans but not life on earth. Nanotechnology might have that non-survivable factor in it's prime, but we're no where near that now.

As for Pheidippides, aren't myths wonderful? Still doesn't outdo the Zulu who were 19th century.

As far as the neolithic age, we were top predators for the last 200,000-250,000 years, but I wouldn't say that we were firmly established as the ultimate top of the food-chain until we started to form permanent settlements and could really influence our environment-after all, the cave bear successfully kept us out of large swaths of territory for a long time. In modern times, so has the Tzitsi fly (I hope I spelled that right), but in that case, it's inevitable that we have or will push into those areas. A major plague or natural disaster could have wiped us out before, or another animal-Neanderthal for instance-could have taken our place, or we could have not survived the last ice age. Things that keep us on top are communities, agriculture, and advanced toolmaking. Until we had those, our position on top of the food chain was precarious. I'll concede that we may have been THE top predator for the last 20,000 years, but I still think the last ice age could potentially have wiped us out.