Could life in solar system complicate space settlement?

I don't think either theory is very plausible, the idea that collective life acts on the environment to make it better for life, or that collectively that single celled microbial life acts against multicellular life.

Evolution shows that life will grow, expand, and grow more complex given time and resources. The effects on the planet are irrelevent, life acts in its self interest without regard to the planet. The exception being humans, since we can decide what we do based on its effects on the planet.
Brooks

--- In spacesettlers@yahoogroups.com, Lucio de Souza Coelho wrote: