Adaptive value of complexity

One might think that the reason complexity is not more widespread in biology is that somehow it is too sensitive to perturbations. But in fact, as discussed in Chapter 7, randomness and complexity tend to lead to more, rather than less, robustness in overall behavior. Indeed, many even seemingly simple biological processes appear to be stabilized by randomness—leading, for example, to random fluctuations in interbeat intervals for healthy hearts. And some biological processes rely directly on complex or random phenomena—for example, finding good paths for foraging for food, avoiding predators or mounting suitable immune responses. (Compare page 1192.)