Evolution of competitiveness
Competitive ability is an important determinant of success in virtually all organisms, including humans. Individuals therefore invest in characteristics that enhance their “competitiveness,” the ability to acquire resources in competition with others. Examples for such characteristics are weapons that provide an advantage in fights; sensory organs that improve the ability to detect and locate resources; an attractive appearance that increases the chances on the mating market; or, in humans, a good education that improves the position on the labour market. All these characteristics are costly to produce. Therefore the question arises: what is the optimal level of competitiveness?
A simple model for this question illustrates the potential complexity of the dynamics of evolution. The model makes one crucial assumption: a higher investment in competitiveness increases the probability to acquire a high-quality resource but at the same time reduces the ability to exploit the acquired resource with maximal efficiency. This assumption is plausible. For example, a tree investing in a high stem outgrows its competitor and achieves a better position when competing for light, but much of the resulting gain in energy is required for the maintenance of the stem.
The figure below shows the evolutionary dynamics of this model. If the variation in resource quality is small (left panel), the population evolves into a dimorphic state, where some individuals invest a lot into competitiveness, while others do not invest into competitiveness at all and instead exploit the low-quality resources that are left over for them with maximal efficiency. If the variation in resource quality is large (right panel), the population remains monomorphic, but competitiveness exhibits cycles with large amplitude. After periods of low competitiveness, investment in competitiveness increases rapidly until a point is reached when competitiveness collapses again. This simple model can therefore explain the huge individual variation in competitiveness that is often observed in animal (and human) societies; the variation between different populations (and countries); and the substantial changes in the emphasis put on competitiveness in different epochs (in animals and in humans). The model has many fascinating facets that cannot be discussed here. Among other things, the model demonstrates the possibility of “evolutionary suicide”, that is, the deterministic evolution of a population to such a high degree of competitiveness that the population will eventually go extinct (because resources are exploited with low efficiency).
Figure: Individual-based simulations of the evolution of competitiveness, the ability to acquire high-quality resources in competition with others.
Reference: S.A. Baldauf, L. Engqvist & F.J. Weissing (2014). Diversifying evolution of competitiveness. Nature Communications, in press. (see attached file)
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