Why do we mourn?

Last night the Michael Jackson funeral was being rebroadcast. Halfway through an ep of Dexter my mother asked me to come outside to watch a few vids of MJ dancing and singing (and honestly, it was the first real concert video I'd seen of him. Wasn't impressed). I listened to a bit of the celebrity 'acts' and a few statements, very touching, very poignant and very thought-provoking.

In a time like this, his death inspired world-wide grieving. People's lives were stopped as they took the time to watch the funeral. But what I couldn't figure out was why, from an evolutionary perspective, we mourn. From a social, humanistic, 'realist' perspective, mourning a loved one just seems a natural and intuitive response to death. But could evolution, and evolutionary psychology, explain the phenomena of mourning?

From a simplistic perspective, evolution is all about survival of the fittest. Many social conventions, in the Middle Ages of admiring and lusting for the corpulent to the contemporary age of rake-thin love, these can be attributed to some evolutionary need to pass on our genes. So why is it then that we mourn? Death is such an instrinsic part of survival. You survive because someone else dies. If someone dies then they are weak - unable to produce more offspring.

In terms of utility, it serves no good to cry and feel melancholy about someone's death, especially when considered on such a widespread scale as MJ's death. Why is it that we suddenly admire the work of the dead (such as his music suddenly skyrocketing in sales) and spurn people who mock the dead ("too soon"; Chaser's Eulogy song)? Suddenly, when someone dies, all the jokes we made of them seem less politically correct - no more kiddie jokes. People say "if you made a joke about MJ and paedophilia you shouldn't be mourning because you're being a fake fucker".

MJ's death would signify his weakness (from an evolutionary perspective), so surely the art he produced wouldn't be admired.... but would be shunned? We would want to imitate the art of the strong so that we ourselves may be strong. It's an interesting paradox, or at least a conundrum that evolution never really answers. I've never been gone to go for the whole evolution being the key to our existence (what with being both a humanist and a solipsist and irrationalist).

Of course all my objections rely on a very simplistic view of evolution. A more complex one could argue that mourning is an act that signifies our recognition of a person's strength as a genetic figurehead. One could argue that the strongest form of power would be one where you could affect others even through death. Therefore mourning is a function where we succumb ourselves willingly in recognition - others will observe how we have mourned them and will accordingly imitate they who died in order to achieve the same kind of power through mourning.

But as in all cases of these meta-complexities, one has to ask how it happens in the first instance? Which came first, the mourning or the recognition of the power of mourning? This will still pose the same question to evolution proponents - how does the function of mourning fit in??