All things considered, what is the purpose of the human race? Of life, in general? Biologically it's to create a copy of ourselves and move on. But what then?
This does not entirely mean JUST humans. Granted, we are on the topic of humans, but if you question the human race, then I think you have to question life in general. What would be the purpose of animals, bacteria, parasites, insects, basically any living creature that reproduces.
[actually, now that I just read the question again, I realized you stated all life in general. I still keep my statement as is.]
I personally do not think that there is such a necessary 'purpose.' Because, to me reaching for a purpose is like reaching for a religion to down* to give me all the answers which... no one really knows the answers to. In my stance, I personally just see that life will always evolutiononize [yes, I spelled that wrong] itself to become bigger and better, such as what Unanun stated afterwords, with AI technology. That, however, I think is just evolution on a technological scale, rather than on a human based scale.
*I did not have any intention of being offensive for those who do practice a religion. I personally do not care what religion anyone is in, and do apologize in advance if that happens to offend anyone.