History-dependent tradeoffs in changing environments*

Performance tradeoffs, which simple models typically postulate, are known to themselves evolve. This leads to a curious feedback loop: evolutionary history shapes tradeoff strength, which, in turn, shapes evolutionary future. Using a simple model, I will show that this feedback can lead to counterintuitive consequences in the context of multiple or changing environments: specifically, a direct exposure to some environment of interest will, in general, no longer be the most effective way of achieving highest fitness in it. I will demonstrate three different mechanisms for how alternate exposure strategies can prove more effective: inducing a more evolvable architecture, counteracting a form of “use it or lose it”, or relying on horizontal gene transfer; and will discuss the prospects of linking these theoretical expectations to experiments.