The basic components for life are CO2/O2 (depending on your origins), water, and light. Without these as far as we know, nothing can grow. So how do we colonize a planet with CO2, light and water that has a lot of rocks and is colder than Earth (cough, Mars)? We take lichen of course! The symbiotic relationship of durable Fungus and cyanobacteria are the best candidates for the job since they are found everywhere in the cold arctic and on inhospitable surfaces such as rocks.
An article on plant life suitable for Mars survive tests talks about 2 Canadian lichens, the sunburst (Xanthoria elegans) and the Map lichen(Rhizocarpon geographicum). They were chosen because of their resilience to extreme environments. What Scientists and Astronauts plan to do is place these specimens on Mars and see how they grow. This is known as Astrobiology. When plants or other plant like organisms can survive a trip through space live to grow about it ;p
It is believed that cyanobacteria and other plant like organisms which grow within a rock (such as an astroid) can survive a trip through space (like falling through the atmosphere) and colonize a planet (like earth!)! Lichens are a good earthly candidate for this also because they can resist solar radiation damages and fix nitrogen, which is believed to be heavily present on Mars. Who knows where this might take us! Maybe we could terraform other worlds like in Dr. Who and the Terraphiles! But then I can;t help but think this may cause a worldly event of invasive species and bacteria…
yukunerkblog 