In chapter 6 of The Tangled Bank by Carl Zimmer, we learned that there is a simple equation to describe the rate of evolutionary change:
Rate of evolutionary change = “heritability of trait” x “strength of selection”
In the Rapid Evolution video, TREY the Explainer provides a couple of textbook examples. The three stories covered in 20 minutes include finches in the Galapagos Islands, wall lizards, and stickleback fish. These examples show rapid evolution (and even speciation) within a few decades time.
Stickleback fish from Lake Washington in 1957 and 2006
Image credit: Unknown. (Was used in Seattle Times article)