There are so many things in the world, and those things have so many components! Insects swarm, leaves fall and scatter in the wind, grains of sand form dunes, bodies are built of cells ... in numbers measured not by thousands or millions or even billions, but far far more. Why such seeming redundancy?
Nature may not be so wasteful after all. Mathematicians have studied "cellular automata": idealized simulations on a grid of pseudo-cells, with fixed rules for how patterns change from one generation to the next. It's not easy to make a general self-reproducing system. Typical configurations that can replicate need huge sprawling arrays of cells, delicately arranged. (Or they need comparably complex underlying rule sets.) If there's any sort of threat to stability and growth --- such as competition by other "creatures" or stressful changes in the background "environment" --- then patterns have to be even larger in order to succeed in copying themselves and correcting errors, accidental or induced. And if there's to be growth into new ecological niches, then more individuals are needed so that they can experiment and evolve in myriad directions. Most such experiments fail, but the few that survive offer hope of additional progress.
The breathtaking diversity of Nature is necessary, not arbitrary. When numbers of units shrink, a subsystem tends to get less robust, more vulnerable to bad luck --- and species go extinct, as biologists have documented.
Monday, December 20, 1999 at 06:38:00 (EST) = Datetag19991220