Environmental Stress and Evolutionary Adaptation

Summary

The link between stress and adaptation was extensively explored by Ary Hoffmann and Peter Parsons in Evolutionary Genetics and Environmental Stress (Oxford University Press, 1991). However, some components of the link are repeatedly misunderstood and profit from clarification.

These include:

variation,	which has been a continual source of confusion from the time of the mendelists and biometricians, during the supremacy of the genetic load theoreticians, and into the naïveties of the neutralists;
niche,	which is commonly perceived as a deterministic hole, rather than a dynamic interplay between organism and environment; and
life history,	which is a series of compromise trade-offs, and not a phylogenetically imposed strait-jacket.

A proper comprehension of these concepts leads to the possibility of developing a sensible ecological genetics and a realistic definition of health (defined, following Karl Barth, as ‘the strength to be human’, rather than the somewhat elusive WHO aspiration of ‘a state of complete physical, mental and social well-being’).