Our existence is only based on the collection of, and passing on of information. This is all stored in your DNA, which was passed along to you by countless generations before you.

Your purpose is thus to live to the fullest extent that you are capable of. Then pass along the information that you've attained, plus that of the generations before you, by creating offspring.  They will in turn do the same, if all goes well.

And so the cycle continues, and so you've fulfilled your purpose here on earth.