re: posts on 'are viruses alive'
I also think Ed Rybicki gave a reasoned answer and to a certain extent,
complexity and/or life is in the eye of the beholder.
some of the work on models for early evolution has involved the use of
very small bacteriophage such as Q-beta. The interesting thing about
this sequence of nucleic acids is that it can effectively evolve -
during the replication process there are sometimes mistakes made in the
The environment of the experiment (read: model of primitive earth) is
such that all of the molecules, 'parents' and 'off-spring', compete for
free nucleotides to replicate. If one of the mutant sequences happens to
have higher affinity for the nucleotides that the original and any other
off-spring, it will come to dominate the sequence population. Until it
in turn is supplanted.
The long-winded point I am trying to make is that this relatively
'complex' behaviour is basically chemistry, ie. the higher the
nucleotide affinities and/or the better the template the faster the
replication the greater the number of copies. By the definition Ed
Rybicki posted (nice definition by the way), the individual sequence may
not be alive, but the system is...
Mike O'Hara, Ph.D.