Right so heres the thing;
if I'm am correct (which I think I am) we only have appendix because when we were apes we used it to digest leaves and stuff. Since we're not apes anymore (thats debatable) or at least we don't need the appendix because it can suddenly explode and kill you, when are we gong to evolve and rid ourselves of the timebomb otherwise known as the appendix!?
We have a symbiotic relationship with beneficial bacteria in our gut. There are bacteria in our gut that evolved along with man and helps digest food. The bacteria relies on man to survive and we rely on the bacteria to help break down certain foods and for some nutrients.
Our beneficial bacteria can die when we are sick or when other bacteria invade our gut. Current thinking is that the appendix is a safehouse for beneficial bacteria so after our dissease or infection our gut can be repopulated with beneficial bacteria.
If it wasn't for modern medicine and surgery I probably would have died of a ruptured appendix when I was 5.
Humans do not have trouble digesting raw meat. The problem we have is with bacteria. Most of the time we could eat raw beef from healthy cattle without trouble. We cook beef as a precaution. Chicken and pork on the other hand will make people sick every time it is eaten raw. True carnivores (dogs, aligators, sharks, etc) have short but very acid digestive systems that kill harmful bacteria; they can eat putrid meat that would probably kill a human.. Human digestive tract is longer to deal with extracting sparser nutrients from plant foods.
Ok I'm not sure if there is another use for the appendix, and I cant be bothered to check, however in response to your evolution question (assuming there is no other function...)
Evolution is slow and takes thousands of years... so it will probably happen eventually... although you have to remember that natural selection works in a way that people who dont have an appendix have a survival advantage over people who do have one... today because of modern science and technology there's not that many people dying from a burst appendix... natural selection is not being allowed to take its natural course...
I agree with what it was used for, I still eat rawish meat sometimes... Mmmm Rare steak... But that could be why it hasen't dissappeared with evolution, but think on the other side of the box, we have no use for it anymore. Thats right now, our bodies might be trying to say something like an internal instinct that we can figure out or even find, but the appendix could be around to be used in the future... For something we will never know until it happens and everything is turned back on... hmmm I dunno :) haha
Actually, it was for digesting raw meat. But, since we cook our meat now, our appendix is useless. Our bodies nolonger produce the hormones for our appendix to work, so we can't use it. I can't tell you why it explodes though. Maybe it gets infected?
The beneficial bacteria theory is new to me and very interesting. I wonder if studies have been done to see if people without appendices have greater instances of bacteria-related digestive problems.
*** I can't tell you why it explodes though. Maybe it gets infected?***
I think it just wants your attention. Like a spoiled child... holding their breath to get their way... uhh... then exploding...
Approximately 1 in 100,000 people are born without an appendix, so evolution to do away with the appendix is slowly taking place.
They Actually have some interesting information and theories here about it. http://en.wikipedia.org/wiki/Vermiform_appendix