if we talk about the possibility of life in ur solar system we should expect only primitive(or even a bit advanced) microbes.....expecting intelligent life forms wud be foolish........but this wud be a breakthrough.....scientists are expecting some some form of life on saturn's moons like titan and encelidus but without success (till now)

however if we talk abt intelligent life forms like humans that is possible only in exo planetery systems.if we consider Frank Drakes equation for this there may be millions of worlds like urs out there where life has developed and evolved and some creatures like us have been able to withstand the test of time.

(in fact the main aspect of ET is even if life  evolved to humans is it being sustained)

hope it is clear u may rate...plz