Evolution doesn't exist anymore. Since people have a brain they have tried to use it. Sadly the more clever they thought they were the more they were fighting against evolution. Today it is considered socially desirable to do everything possible to actively fight against evolution, namely survival of the fittest. If we some day get wiped out by ourselves then evolution didn't fail us, we failed evolution.

As a species we are continually evolving, we just dont see it on a Yearly basis. We are slowly getting bigger, stronger and smarter as time goes by. We are perfecting.

The only problem we may face going forward is one of overpopulation, leading to a lack of resources and the eventual downfall of society.

The end of humans will be.... humans.

We didn't evolve enough. We aren't peaceful enough. As a whole, we aren't SMART enough (global warming).

Nature itself isn't peaceful. We're just capable of disrupting others in Earth in a scale that is easily visible.

Seeing how teenagers are nowadays... we're already de-evolving

You're a professor aren't you? You should correct some of them.

I'm not even sure where to start on this

Until there's no living thing in existence evolution hasn't failed. Humans are one of the most adaptable animals in known existence. We can find ways to survive in many different environments using technology. Our warm-bloodedness already allows us to survive in a wide range of environments naturally. And since we're the only animal that can leave Earth, we're the only species that can escape its fate, and persist.

I only see a few threats to humanity: nuclear conflict, asteroid impact, Yellowstone blowing. I think humans are in the final stages of nuclear conflict being a threat - the world is too interconnected for it to be viable. We really only have to worry about an asteroid impact and Yellowstone. Each of those things can be averted or stifled as our knowledge and technology grow. It's a race against the clock.

Are human's next behind dinosaurs....

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

...no.