QUESTION:
How might life forms on Mars be similiar to ones underwater?

ANSWER from Bruce Jakosky on May 12, 1997:
This is a difficult question.  If there
is life on Mars, then it could not live on the surface - the environment
there lacks water and has too much ultraviolet light.  Rather, it might
live either in subsurface water associated with volcanism or in
groundwater well below the surface.  On Earth, there is life that lives
in these types of environments.  In fact, life on Earth may have first
arisen in hydrothermal vents, where water at the bottom of the ocean is
heated by hot volcanic rock; and, life still thrives there today.  Martian
life probably would be most similar to terrestrial bacteria - those are the
simplest life forms that exist on the Earth, and many are capable of living
in these types of unique environment.