There's no predictated purpose in our lifes, nor in any life or thing. Not even in the universe.
As for the latter afirmation, it can be better explained in this vid: Spoiler:
http://www.youtube.com/watch?v=7pL5vzIMAhs" frameborder="0" allowfullscreen>
And of course sometimes we humans are able to decide which purpose we want to live for. As we know about the interaction between us and the rest of the world, we trace some purpose for our lifes.
But putting aside our family and parents desire, do we have a bigger purpose for our lifes? My answer to this question is no.
We can't say that something has predicted our entire life and "made" it to follow some kind of rule.
Also, people who answer "yes" to this question are most likely to believe in a higher entity, such as some god. Is good to say, in that case, that many times the purpose that their gods supposedly put on their lifes is the purpose that they want themselves to follow.
Surely they woudn't live a life in which the supposed purpose is to be eaten or enslaved.