Well, over a sufficient timeline, humans will just be a common ancestor species of a series of new, distinct species. That's how it goes.
It's a bit disappointing to think that billions of years of evolution would result in only hardy bacteria or algae surviving to represent life. I think the continuation of consciousness is a more interesting goal... whether it happens in our carbon-based biology or in some other way is a secondary concern.
You seem unaware of extinction events. Humans are not guaranteed descendent species.