The Search for Extraterrestial Life

At the moment, it is easy to get money to search for exoplanets. Congress has mandated NASA to do just that. They are to: "acquire an improved understanding of how planetary systems form and evolve, including better descriptions of planetary system architectures, compositions, and environments. Second, they need to learn enough about exoplanets to make informed predictions about habitability, and to make meaningful searches of alien life in distant star systems." Key questions are, is life unique to Earth or is it pervasive throughout the Universe? Are all the forms of life basically the same, or do they differ? Did life on Earth get started from non-biological sources, or were we "contaminated" from space.