geobiologic

Perhaps Mars is an example of a rocky planet that had sparse microbial life (relative to Earth) and therefore Martian biology had little net effect on the evolution of the Martian surface and atmosphere leading to a relatively short geobiologic lifespan and therefore no chance for the advent of complex life.

Random feeds from Syndic8.com 2009

Still, the really interesting planetary bodies in our solar system, from a geobiologic point of view, are a couple of the moons that orbit the giant gas planets Jupiter and Saturn.

Random feeds from Syndic8.com 2009

For detecting extraterrestrial life we should not only focus on whether or not carbon / water-based life forms can be supported on a rocky planet (geologically active and rocky surface (not a gas giant), like Earth, Mars, Venus and Saturn's wildly interesting moon, Titan), but whether or not a planet possesses surface properties that demonstrate a predictable pattern of behavior over time (for example, a substantial and dynamic atmosphere (like the consistent addition and removal of Methane from Earth's or Titan's atmosphere)) which is independent of the specific chemistry and physics operating on the geobiologic level.

Random feeds from Syndic8.com 2009