Life on Mars? New fossils show it’s possible

22 Aug 11 – Newly discovered fossilized, single-cell organisms that thrived without oxygen billions of years ago suggest that life could exist on other planets where oxygen levels are low or non-existent.
Examining thin slices of rock under the microscope, a team of Australian and British geologists have discovered fossilized, single-cell organisms that are possibly the oldest known fossils on earth.

See:
http://www.evolutionaryleaps.com/Life_on_Mars-New_fossils_show_it_is_possible.htm