Benefiting from the Bubbling Evolutionary Cauldrons

Abstract

Abstract We begin this chapter with an examination of what we mean by evolutionary adaptations, by contrasting simple, continually fine-tuned adaptations, such as selection for mimicry patterns in stable ecosystems, with astoundingly flexible mechanisms such as our adaptive immune systems. Flexible mechanisms can adapt organisms to continually changing conditions. This is done, not by anticipating the future, but by drawing on capabilities that have evolved during continually changing conditions in the past—a process that the author has named “the wisdom of the genes.” We trace the remarkable role played by gene transfers in the evolution of the immune system in jawed vertebrates like us. We show how immune systems in other animal groups are not as flexible, because they have not utilized these “borrowed” genes in the same way. The adaptive immune system arose because of the evolutionary resources provided to our ancestors by the ecosystems in which they lived, and because of the wide range of challenges by the pathogens and parasites that inhabited those same ecosystems.