Expert: Jayendra Upadhye - 1/11/2005

Question
If life existed on Mars a long time ago, what kind might it be?  What would it look like, and how big would it be?

Answer
Hi,
As per current estimates, there WAS flowing water on mars in the early history of the planet.
However it lost most of its surface water, to space owing to lower gravity and the early freezing of the core.
The ensuing loss of a magnetic shield exposed the water to direct blast of the solar wind.
The thin atmosphere also did not help.
So most of the water was lost quite early.
We must understand here, that even on earth, with all its water, life took almost 2 billion years to start.
And almost 2 billion more to really get going!
Till then (the cambrian explosion), the algae with photosynthetic properties was just doing one thing...convert CO2 into breathable oxygen. True life as we know it, with mobility as we understand it (fast) was impossible due to very low oxygen content of the atmosphere.
about 570 million years ago, all that was set right and the cambrian explosion started a proliferation of all life "as we know it". [previous soft bodied animals could hardly be fossilized].

THE POINT IS, if mars followed a similar plan, then if the water had already dispappered early before the cambrian part was reached, we can at most expect fossilized bacteria in its rocks! Nothing more.

IT is important to understand that as geological ages go, LIFE has come "on stage" only in the last moments!
[600/4500 = 0.1333 or 13.33% of the time]

The "ALH" mars metorite showed the same!

ref:- http://www.pbs.org/wgbh/evolution/library/03/4/l_034_02.html
for all info on the cambrian explosion.

ref:- http://calspace.ucsd.edu/marsnow/library/science/mars_meteorites1.html
for a beautiful presentation on the alh mars meteorite.
Jayen