Effects of selection on evolvability over time.

<p>Evolvability was measured as the rate of adaptation and the production of phenotypic variation assessed under selection in novel environments. Measures were determined using 100 networks randomly selected from each population every 2000 generations. (<b>A</b>) Mean evolvability (+/− SE) over time. (<b>B</b>) Mean production of phenotypic variation (+/− SE) over time. Results for the fluctuating environments are for red noise with a 50 generation period length and its corresponding white noise control.