A fire kills the 95% of the salamanders in a forest. Prior to the fire, the salamander population had a lot of different colors (from light yellow to dark green), but the majority of individuals were a medium shade of green and blended quite well with the vegetation. After the fire, the few remaining individuals were all light in color. A decade later, the population has increased back to a similar size as the pre-fire population, but there are still only light-colored individuals. What happened here