Search Results

This chapter discusses adaptive diversification due to predator–prey interactions. It has long been recognized that consumption, that is, predation, can not only exert strong selection pressure on the consumer, but also on the consumed species. However, predation has traditionally received much less attention than competition as a cause for the origin and maintenance of diversity. By using adaptive dynamics theory as well as individual-based models, the chapter then illustrates that adaptive diversification in prey species due to frequency-dependent predator–prey interactions is a theoretically plausible scenario. It also describes conditions for diversification due to predator–prey interactions in classical Lotka–Volterra models, which requires analysis of coevolutionary dynamics between two interacting species, and hence of adaptive dynamics in two-dimensional phenotype spaces.

This chapter examines adaptive diversification in language and religion. The historic record contains many examples of the types of diversification occurring in these models. Diversification in languages has been rampant throughout history, and must have often occurred under substantial contact between hosts of diverging language memes. Similarly, it seems clear that religious diversification has often occurred, and continuous to occur, under conditions of substantial contact. The models illustrate that diversifying processes should be expected to operate whenever the likelihood of secession from a dominant culture increases with increasing dominance of the mainstream culture. Intuitively, it is not hard to imagine that the attractiveness of a culture diminishes as the culture becomes more dominant, dogmatic, and perhaps oppressive, and that the desire to stand out and be different increases in increasingly conformist cultures.

This chapter focuses on adaptive diversification due to cooperative interactions. If predation has received less attention than competition as a cause for the origin and maintenance of diversity, mutualistic interactions have fared even worse. There is quite a substantial theoretical literature on the ecology of mutualistic interactions, but only a few studies have investigated mutualism as a potential driver of diversification. There is of course a rather huge literature on the evolution of intraspecific cooperation, and many of these models implicitly address the problem of coexistence between cheaters and cooperators, and hence the maintenance of diversity. However, the origin of diversity in cooperative contributions has only recently been investigated. Most models of cooperation assume that cooperators make a costly contribution to a public good, which is then distributed among certain members of the population.

This chapter views patient care from a population health perspective. The argument for treatment variation strengthens when one considers patient care as a population health problem rather than from the perspective of a clinician treating an individual patient. This chapter shows that randomly varying the treatment of patients with the same observed attributes can provide valuable error protection and information under uncertainty. That is, it may be useful to diversify treatment choice. The chapter explains that implementation of adaptive diversification may be possible in centralized health-care systems where there exists a planning entity who chooses treatments for a broad patient population.