Answering the description.
AI that gets out of hand- definitely not.
Diseases that in space flight are amplified? No, I don't really see how being in outer space can help a life form.
The use of apocalyptic weapons- I like sci-fi a lot, but I don't think we'd let it reach that point. We wouldn't go extinct just like that.
Scientific experiments gone wrong- Okay, I really doubt that one. How wrong can you really get?
Asteroids, gamma rays, interplanetary contamination- Better odds than most. Particularly likely to be asteroids that get the better of us, by crashing to earth. One asteroid left a crater big enough to fit the earth in it on Jupiter. If another asteroid like that is around, we could be in trouble. But again, unlikely.
Overconsumption- No, at that point we'd just have a senseless war to get rid of a bunch of people, so we still have enough resources. A global overconsumption issue seems unlikely to me.
Alien invasion- Why would aliens bother to come all the way to earth? Unless they have really fast ships, that's not a worthwhile trip.
@Donderpants 1. That's just your opinion man 2. It's been shown that Diseases such as salmonella undergo stronger gene expression during space flight 3. You're only acknowledging humans. I can't be F_cked explaining the rest.
Assuming humans aren't the only creature capable of being sentient (I believe we aren't), intelligent life will never go extinct. Once one kind of sentient life form vanishes, another will evolve to replace them.