If this is indeed the case the discovery of even a spoonful of bacteria in Martian soil would strongly imply that more advanced creatures might have evolved elsewhere, if not on the red planet, most certainly on a distant orb. The possibility that evolution takes place elsewhere would enormously expand the possible range of creatures. You can get a sense of this by looking at the three wings pictured above. Here on Earth, the wing evolved separately in bugs, birds and bats. Paradoxically, the possibility that evolution takes place elsewhere might simplify the search for life.
Nature jealously guards ideas that work.
Thus, focusing on the most basic similarities among all living organisms could provide the most important clue to the discovery of alien life. Many scientists believe the best way to search for our origins is to begin with the basics. Stripped to its fundamentals, the universe doesn't get any more basic than hydrogen. The hydrogen atom is the lightest and simplest atom you can think of. Put two hydrogen atoms together and you have the lightest, most abundant and simplest molecule.