Not to bring rain on parade, but the idea of slow, gradual evolution is an old (defunct) concept. Scientific study over the last few decades has revealed a process of impressive movements followed by plateaus of little change..A study of finches in the Galapagos Islands from 20 yrs ago revealed a dramatic 50% shift in the size of small finches over the course of one season during a period of environmentally-induced stress. The following generation returned to “normal” when the stressor passed a season later..(compare to studies of rapid mosquito immunity to DDT).But change is easiest when the population of a species is small. Differences of any kind will have an outsized impact on future generations. .Large groups are much less inclined to change, as differences tend to be diluted and diffused in the greater body, much as a pinch of salt might turn a thimble full of water bitter, but will be undetectable in a bowl..As for adaptation via externalities, change through behavior is a common and widespread “shortcut” that bypasses the timeframes of DNA..Giraffes have no immunity to the unpleasant sap exuded as a defense by the acacia tree. Evolving a biological counter would be a crapshoot, and one for future generations only. But giraffes have learned to eat a few leaves and then move on, before the unpleasant sap flows. They also know to attack the trees downwind first, and then move “up” the treeline, since the trees release a warning chemical that alerts other acacias nearby that an attack is imminent, which triggers them to push sap into their leaves. A behavorial response that bypasses biological need..People put on coats when it’s cold, irrigate crops when it’s dry, spray lethal cocktails of chemical death on pesky bugs and rebel groups when needed. It’s a very long and old story..Adaptation is rapid because it has to be. Were it not, life would have kicked it ages ago.