“He was saying that if a particular variation—say color vision—could give an individual a slight advantage over its peers, almost the entire population would be able to see in color over many fewer generations than we would imagine. Let us assume that color vision has a “selective advantage” of 1 percent, meaning that individuals with this trait produce 101 viable offspring instead of 100 (maybe color vision allows the individuals to locate higher-quality fruits in the forest). Thus, the selective advantage here is equivalent to compound interest or annualized return. The advantage accumulates and grows exponentially over generations. Thus, in the second generation, the 101 offspring with color vision produce 10,201 offspring who can see color (101 x 101), whereas the 100 “normal” offspring produce 10,000 “normal” offspring (100 x 100). This slight advantage compounded at 1 percent per generation yields dramatic change over time.”