I am an aerobic protokaryotic organism whose ability to survive and prosper in an unstable world is dependent on an ancient symbiosis with an anaerobic eukaryote that moderates the fluctuations in my micro-environment (see http://setiathome.ssl.berkeley.edu/cgi-bin/cgi?cmd=view_feedback&id=6747). This eukaryote is irrevocably bound to the symbiotic contract by its vicarious dependency on the redox properties of the toxic element oxygen. A subset of my proteome is provided by my symbiotic partner, relieving me of the need to maintain part of my original genome. Forty five years ago a group of my siblings and I formed a separate colony with a totipotent eukaryotic ark cell that has subsequently become a metazoan organism.
My symbiont secures the raw materials that I require to propogate intermittently in other colonies. In return I expedite most of the energy transformation and entropic management required for our mutual metabolic needs.
I salute my eukaryotic symbiont and acknowledge that it has allowed me to colonise parts of our world that were formerly inaccessible.
Thoughts about SETI and SETI@home
Chemical species that are characterised by a propensity to form copies of themselves will do so for no reason other than that they are compelled to behave in that way by the fortuitous arrangement of electrons in their outer shells. There is no justifiable reason for excluding such systems from the set of "living" things. Any two different self-replicating systems that share an environment will passively compete for those raw materials that are required by both for replication so evolution is inevitable. Any system large enough to support sufficient raw materials to allow repeated generations of molecular copies is a potential cradle of life. The presence of a suitable source of energy to facilitate the reactions that comprise self-replication provides an opportunity for such cradles of life to realise their potential. Self-replicating chemical systems, repositories of raw materials and sources of energy abound in the observable universe.
Viewed in this way it seems probable that life is widespread and its presence in any locale (on a cosmic scale) is the rule rather than the exception. Self-replicating systems may remain dispersed within a chemical soup or may organise in discrete units. Discrete units may remain isolated or may associate in large colonies as survival machines. Large colonies may remain generally solitary or may form socially structured metacolonies.
We are unlikely to discover whether living systems other than our own have found evolutionary advantage in advanced intelligence unless we look. Let's look. Let's anounce to the cosmos the presence of one living system that has evolved in this way. Let's not be distracted by imagined dangers. Like our own eukaryotic symbionts let's act without malice for the good of the universe.
SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.
