Astronomically speaking, life is a numbers game, given the size of the universe as we know it so far. Mathematicians and physicists have both given examples of why the idea of there being no other intelligent life in the universe is statistically very low, given what we know about our biological origins on Earth. The right conditions arise, for the right amount of time, and you introduce the potential for the mechanisms of evolution to occur.
Given this, we can say "sure, the Jockeys found a planet in the habitable zone, at the right geological stage and next to a main sequence star, and seeded their goo," and that's dandy. The big problem arises in the end-result, right? And how closely related to the Jockeys it would be?
I have several thoughts on this. To begin, the first scientific question that needs to be asked is "why Homonids?" The answer to that, according to modern science, is through the mechanisms of genetic drift, mutation, and natural selection combined with environmental stimulus. To put it bluntly, "it was random." Even this basic pillar of biological knowledge presents some interesting questions, such as:
Why homonids, and not a reptilian form of conscious, tool-using, tribal life? Or aquatic? Or avian? What occurred that brought about the proper environmental stimuli, and physiology, to allow for the development of the forebrain and our eventual leap to true self-awareness and cognitive, abstract thought?
Can we gleam a theory from this that only the homonid lifeform is capable of achieving this psychological state, thanks to the development of things like thumbs, tongues, and even tools that other species wouldn't require, environmentally speaking? Land-walking, tribal groups of bipeds have thus far been the only link in our evolutionary chain, but does this betray some sort of undiscovered set of rules, or is it, again, simple luck?
Could birds and fish and frogs and insects ever have entered an environment that provoked these traits, and then been lucky enough to reproduce the proper mutations with enough time to not be wiped out by an extinction event?
As far as I know, modern evolutionary biology doesn't exactly offer us any other answer than "random, thanks." All of my other questions have been answered the same: random.
Honestly, and you will probably balk at this, I'm not in the 'random' camp. I think that's a theory that will be disproven in the future, and consciousness will be better recognized as a much more significant leap than a simple mutation, hence why it presents us with it's own internal set of problems (completely oustide of the influence of environmental stimuli) a new phase space, a directional sort of 'point,' and the complete reversal and elimination of the natural evoluationary process by our very presence on the planet.
I debate with many more intelligent than I on this subject, constantly, so feel free to comment please. I'm not easily offended.