In Science this week: Complexity and Diversity
The mechanisms for the origin and maintenance of biological diversity are not fully understood. It is known that frequency-dependent selection, generating advantages for rare types, can maintain genetic variation and lead to speciation, but in models with simple phenotypes (that is, low-dimensional phenotype spaces), frequency dependence needs to be strong to generate diversity. However, we show that if the ecological properties of an organism are determined by multiple traits with complex interactions, the conditions needed for frequency-dependent selection to generate diversity are relaxed to the point where they are easily satisfied in high-dimensional phenotype spaces.
"When you model one trait at a time--in isolation--you often find that ecological interactions aren't strong enough to drive divergence. But with many traits acting in concert, even very weak interactions can generate diversity. Our approach mirrors the complexity of reality more closely--if you think about it, all living organisms have at least dozens, if not hundreds, of ecologically relevant traits," says Doebeli.