The Fragility of Evolution: Part One

Abstract

This article argues for a shift in evolutionary metaphor-from fitness and the elimination of the less fit to fragility and passage through fragile periods of change. Childhood, for example, can be viewed as state of protected weakness, allowing time for more neural development, learning, and play. Similarly, evolutionary change can be released precisely when competitive pressure is relaxed. The fragility of evolution in time extends to several biological domains. The genetic system exhibits a surprising fluidity, whether from mobile genetic elements or hypermutation due to stress. Through gene duplication, organisms build up redundancy, which can more readily diverge into novelty. With endo-symbiosis one organism becomes incorporated into another, merging genomes, membranes, and metabolisms. As a result novel structures and genetic restructuring occur, making for profound evolutionary change. In a sexual life cycle, gametes within a species group fuse and amplify subtle variation. Hybridization, or unions between atypical sexual partners, can cause instant speciation and an instability that leads to more evolution. With development organisms go through rapid morphological change and sensitive transition phases. Importantly, dissociation of developmental modules in both temporal and spatial ways allow for evolutionary novelty to emerge. Several lines of evidence lead to the hypothesis that the organism's inner matrix can respond to stresses and help shape a fluid genome. In a second article, three more biological domains will be examined, in which organisms and environment more obviously interpenetrate: the remarkably plastic neural/behavioral system, novel synergisms between organisms, and the multiple, complex dynamics of ecosystems-all of which help to generate life's outstanding diversity. Last, the protection of fragile human populations will be discussed.