No life - kinda (Score 3, Interesting)

I voted for "no life", but I'd like to ameliorate that a bit. It's entirely possible that there could be small pockets of life, perhaps near volcanic vents or in subsurface water reservoirs. What I mean is that while there may be life, I doubt that Mars has a global ecosystem. Both atmospherically and geologically, it's too uniform. If you look at Earth's geological history, life has caused vast changed to the planet - the most obvious being, of course, the presence of oxygen in our atmosphere. Mars shows none of these earmarks, implying that it simply doens't have the biomass to affect Martian environment on a global scale.