Survival of the Fittedest

An unacceptable level of teleology crept into Lewis Thomas' article on viruses (The Scientist, April 6, 1987, p. 13). They do not have functions, they just have properties. The small and simpler viruses are just chemical structures, perpetuated because they delude pre-existing synthetic mechanisms into copying them. They can do that effectively only if they survive in the hostile environment of a host cell. It is hostile more because of scavenging enzymes than because of directed host activities (such as antibodies and lymphocytes). That probably explains the compact way in which parts of so many viruses are bonded together. They are not bonded because they are viruses; rather unless their parts were thus fitted together they would have little chance of persisting long enough to be viruses. There is then "survival of the flttest"—or fittedest. All that seemed fairly obvious to many of us 40 years ago....